Band 8, Heft 1

Iota carrageenan gels prepared with various CaCl2 content were completely dried and then swelled in water vapor. Steady-state fluorescence (SSF) technique was used to monitor the swelling process of each iota carrageenan gels at various temperatures. Pyranine was used as a fluorescence probe. Apparent fluorescence intensity, I increased as swelling time increased for all gel samples. The increase in I was modelled using Li-Tanaka equation from which the swelling time constants, τ 1 and cooperative diffusion coefficients, D c were determined. It was observed that Dc increased as the swelling temperature was increased. On the other hand at each temperature, it was seen that D c decreased as CaCl 2 content was increased. Activation energies for swelling were obtained and found to be 60.5, 61.0, 61.5 and 62.8 kJmol -1 for the gels prepared with increasing amount of CaCl 2 content.

The present paper deals with graft copolymerization of binary vinyl monomer mixtures onto flax fiber. Maximum grafting (86.02 %) has been found with MMA+EA binary mixture. Percentage crystallinity and crystallinity index of graft copolymers were measured with X-ray diffraction (XRD) technique. Crystallinity of flax decreases on grafting with binary vinyl monomer mixtures. Flax showed the highest value of percentage crystallinity (76.96 %) and crystallinity index (0.7005) in comparison to Flax-g-copolymers.

The current work has focused on the preparation and property of a novel fluorosilicone oil with polyfluoroalkyloxypropyl group substitution. Using fluoroalcohols as materials, three kinds of fluorosilicone oil, named [3-(2,2,2- trifluoroethyl-oxy)propyl]methylsilicone oil, [3-(2,2,3,3-tetrafluoropropyl-oxy)propyl] methylsilicone oil and [3-(2,2,3,3,4,4,5,5-octafluoropentyl-oxy)propyl]methyl silicone oil, were prepared via condensation, hydrosilylation, cyclization and ringopening polymerization. All the fluoroalkyl derivatives were characterized by NMR, FT-IR, MS and elemental analysis technique. The thermal stability of these fluoroalkyoxypropylmethylsilicone oils was identified to be excellent by thermogravimetric analysis. [3-(2,2,3,3,4,4,5,5-octafluoropentyl-oxy)propyl]methyl silicone oils with different viscosity were prepared by varying the amount of endblock reagent in the polymerization, and the antifoam property of these fluorosilicone oils was investigated. The result showed that the antifoam property of octafluorosilicone oil with higher viscosity was better than that with lower viscosity.

In the present work, ethylene polymerization kinetics was modeled using moment equations. According to the results obtained, the molecular weight distribution of each active center follows a Schultz-Flory distribution. However, the molecular weight distribution of polymer produced is much broader than a Schultz- Flory distribution. Besides, the order of polymerization with regard to monomer concentration is higher than unity. Moreover, the catalyst active centers deteriorate in the presence of hydrogen and consequently catalyst yield drops; nevertheless, polymerization kinetics is not mainly affected by hydrogen. Hydrogen also reduces polymer molecular weight since it is a strong transfer agent in olefin polymerizations. Notwithstanding, it does not affect polydispersity index. Last of all, although increasing cocatalyst concentration does not influence the activity of active centers, it lessens the molecular weight as a transfer agent

Two novel poly (aryl ether ketone)s with anthracene moieties in the backbone were synthesized through the conventional nucleophilic aromatic substitution polycondensation for the first time, by using a new bisfluoro monomer, 9,10-bis(4-fluorobenzoyl) anthracene (AnBF). The structures of obtained polymers were confirmed by NMR, IR and UV characterizations. The polymers have high molecular weight and show good solubility in common organic solvents. Differential Scanning Calorimetry (DSC) indicates that they are vitrified polymers with high glass transition temperatures above 188° Thermogravimetric analysis (TGA) shows that these polymers have good thermal stability in nitrogen atmosphere with a 5% weight loss (TGA-5%) above 465°.

The effect of melting conditions on the crystallization kinetics of poly(trimethylene terephthalate)(PTT) was presented by means of depolarized light intensity (DLI) technique. The kinetics of PTT crystallization from melt depends on melting conditions and primarily upon the temperature of the melt. Higher melt temperature or longer time of melting may cause a reduction of crystallization rates at the melt temperature range from 506 to 531 K. Crystallization mechanism of PTT crystallizing from various melting conditions has been discussed according to Avrami kinetics parameters and morphology study. The reduction of the rate may result from two reasons: 1) the decrease of regularity such as residual nuclei in the PTT melt which lead to a reduction in the number of heterogeneous nuclei in the crystallization process; 2) the decreased spherulitic growth rate of PTT with higher melt temperature or longer residence time for melting

Chemical modification of polymeric materials is one way of polymer waste management. In our study, expanded polystyrene waste (EPS), used as the reference material, was converted into polymeric flocculants by the sulphonation reaction. Thus, poly(styrenesulphonate) acids (EPSS) were obtained from EPS during the sulphonation process with sulphuric acid as the sulphonation agent and Ag 2 SO 4 as the catalyst under both conventional heating and microwave conditions. At the termination of the process the products were precipitated in the form of sodium salts (NaEPSS) in the reaction with Na 2 CO 3 and their characteristics were given. The influence of temperature and time of reaction on the properties of EPSS and NaEPSS was studied and compared with conventional and microwave conditions. The results showed that the sulphonation process performed under microwave irradiation allowed us to receive products with properties similar to the ones obtained under conventional conditions but the reaction time was substantially reduced from 1 and ½ hour to 15 min.

A pyridine-based diacid containing ether linkage was synthesized via reaction of 2,6-dichloropyridine with 3-hydroxybenzoic acid in presence of potassium hydroxide in dimethyl sulfoxide (DMSO). The corresponding diacid chloride was synthesized by reaction of the diacid with oxalyl chloride. New poly (amide-ether)s were prepared by solution polycondensation reaction of the prepared diacid chloride with different commercial aromatic diamines. The synthesized polymers were characterized by elemental analysis, IR, and 1 H NMR spectra, wide-angle X-ray diffraction, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC); inherent viscosity and solubility were studied. These polymers showed high thermal stability and good solubility.

Copolymerizations of ethylene/1-hexene were conducted using different zirconocene/AlR 3 /B(C 6 F 5 ) 3 catalytic systems at 50°C. When AlEt 3 was used as alkylate agent, very low copolymerization activity was observed with both bridged catalyst Et[Ind] 2 ZrCl 2 and unbridged zirconocene Cp 2 ZrCl 2 in-situ activated with B(C 6 F 5 ) 3 . In appropriate Al/Zr mole ratio using Al( i -Bu) 3 , the catalytic activities of both zirconocene catalytic systems were similar to those of sophisticated zirconocene/methylaluminoxane(MAO) catalytic system. The catalytic activities, comonomer incorporation and molecular weight of the copolymer synthesized with Et[Ind] 2 ZrCl 2 /Al( i -Bu) 3 /B(C 6 F 5 ) 3 were higher than those obtained with Cp 2 ZrCl2/Al( i - Bu) 3 /B(C 6 F 5 ) 3 . The effect of the concentration of 1-hexene on catalytic activity, copolymer molecular weight, and comonomer incorporation was investigated. The complicated “co-monomer effect”, together with an increase in comonomer incorporation, a decrease in the copolymer molecular weight, was found when the comonomer concentration was increased.

In this study, we designed a two-layer hybrid Anti-Reflection/Anti-Static (AR/AS) thin film. Two kinds of UV-curable fluorinated compounds were synthesized as low refractive index materials, and a TiO 2 sol combined with a conducting polymer, poly(3,4-ethylenedioxythiophene) was made by the sol-gel process for use as a high refractive index material as well as a conducting layer. In order to determine the most optimized AR/AS system, the spectral properties were simulated with the refractive index of each layer. According to the simulated results, a high refractive index layer was deposited on the hard coated poly(ethylene terephthalate) (PET) substrate by the spin coating technique, and a low refractive index layer was spin coated on the low refractive index layer. The reflectance and transmittance were measured by UV-VIS-NIR spectroscopy. It was found that the measured reflectance and the maximum transmittance of the AR/AS film were 0.71 % R at a wavelength of 550 nm and 93 % T in the wavelength range between 400 and 700 nm, respectively. The surface resistance of the AR/AS film was 10 8.6 ohms.

Nucleophilic substitution reaction of 5-amino-1-naphthol with disodium- 3,3'-disulfonate-4,4'-dichlorodiphenylsulfone (SBCPS) in the presence of sodium hydroxide and subsequent acidification resulted in a new diamine monomer named as 3,3'-disulfonic acid-bis[4-(5-amino-1-naphthoxy)phenyl]sulfone (DANPS). This monomer containing ether, sulfone, and bulky naphthyl groups was used to prepare two series of new copolyimides via one step polycondensation reaction. This sulfonated diamine (DANPS) was polycondensed with two unsulfonated diamines, 4,4'-oxydianiline (ODA), and m-phenylenediamine (m-PDA) and 1,4,5,8- naphthalene tetracarboxylic dianhydride (NDA) to prepare copolyimides with controlled degrees of sulfonation. Monomers and polymers were fully characterized with common methods and the physical properties of the polymers including thermal behavior and stability, viscosity, and ion exchange capacity (IEC) as a criterion for evaluation of the performance in fuel cell membrane were investigated.

PANI films were deposited on glass substrates by in-situ polymerization and characterized by UV-VIS spectroscopy and atomic force microscopy. A method is developed to accurately analyze ellipsometric data obtained for transparent glass substrates before and after modification with absorbing polymer films. Surface modification was made with an overlayer such as polyaniline (PANI), which exhibits different optical properties by varying its oxidation state. First, the issue of using transparent substrates for ellipsometry studies was examined and then, spectroscopic ellipsometry was used to characterize absorbing overlayers on transparent glasses. The same methodologies of data analysis can be also applied to other absorbing films on transparent substrates, and deposited by different techniques

Corona poling behaviours of optically active photochromic copolymers derived from methyl methacrylate (MMA) and the methacrylic ester of ( S )-3- hydroxy pyrrolidine linked through the nitrogen atom to the highly conjugated photochromic 4'-(β-cyano-β-(methylsulfonyl)vinyl)-4-azobenzene moiety, have been investigated with the aim to evaluate the effect on the non-linear optical (NLO) properties originated by the presence of inactive side-chain MMA groups along the main chain. The NLO properties of in situ corona poled polymeric films have been studied by second harmonic generation (SHG) measurements. The d33 values of the investigated polymers were determined to be in the range 10-86 pm/V after corona poling. The temporal and thermal stability of the optimal SHG signals obtained after corona poling process of all the macromolecular materials has been investigated and compared. The results indicate that the maximum of these properties can be obtained at a molar content of photochromic units around 20- 40%.

Two salts of the biopolymer chitosan were prepared in aqueous medium by employing an excess of HCl or HNO3 in order to ensure neutralization of all NH 2 -chitosan groups. Chitosan salts were extensively dialyzed in dionised water and dried at 40 ºC until film formation. The films were characterized by thermogravimetry, FTIR and conductimetric tritration. QH + Cl − and QH + NO 3 − salts were viscosimetrically evaluated in free acid aqueous solutions in the presence of NaCl to control ionic strength of the medium. Unexpected high intrinsic viscosity values were obtained at low ionic strength when QH + NO 3 − salt were evaluated. Smidsrod´s approach was employed to estimate the stiffness parameter of both salts and B = 0.084 and 0.120 for QH + Cl − and QH + NO 3 − , respectively, were obtained.

The mechanical properties of different high impact polystyrene (HIPS) were determined by means of impact and tensile tests. Impact strength (IS), yield stress (σy) and Young’s modulus (E) were evaluated as a function of the rubber phase morphological features such as type and particle size (Dp), volume fraction (Φ) and interparticle distance (IPD). In order to evaluate the changes produced in the rubber phase, the initiator, chain transfer agent (CTA), and type and concentration of SB copolymer were varied during the synthesis of HIPS. Transmission electron microscopy was used to analyze the materials’ morphology and the data obtained reveal that the Dp and Φ increases mainly with an increase in the PB content and/or with the use of CTA and decreases with an increase in initiator concentration. In addition, E and yield stress diminishes when increasing the dimensions of the rubber phase (Dp and Φ), contrary to the IS. The IPD/Dp ratio also indicates the dependency of the mechanical properties with respect to the rubber phase features. An increase in IPD/Dp provokes an increases in E and σy, whereas IS diminishes.

In this study, a novel fibrous adsorbent made by grafting 4-vinyl pyridine (4-VP) and 2-hydroxyethylmethacrylate (HEMA) monomer mixture onto poly(ethylene terephthalate) (PET) fibers was used for removal of Congo red (CR) in aqueous solutions by a batch equilibration technique. The influence of treatment time, pH of solution, dyes concentration, and reaction temperature on adsorbed amount was investigated. Adsorption time of 60 min. was found sufficient to reach adsorption equilibrium for CR. It was found that the adsorption isotherm of CR fits to Langmuir type isotherms. The highest adsorption capacity was found to be 11.87 mg CR per gram adsorbent. The adsorption rate of CR is much higher on the comonomers grafted PET fibers than on the ungrafted PET fibers. CR was removed 97 % when the initial dye concentration was 5 mg L -1 and 38% at 150 mg L -1 by monomers mixture grafted PET fibers. The adsorption of the dye was endothermic in nature (ΔH°=45.3 KJmol -1 ). It was found that the reactive fibers are stable and regenerate by acid without losing its activity.

Beads of the sodium alginate (NaAlg) were prepared by dropping aqueous sodium alginate (NaAlg) into glutaraldehyde (GA) as a crosslinker and HCl as a catalyst mixture solution. Beads prepared were used to deliver a model non-steroid, anti-inflammatory drug, indomethacin (IM). The beads were characterized with Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Chemical stability of the IM after encapsulation into beads was confirmed by FTIR. SEM photograph indicated that alginate bead has spherical shape and rough surface. Preparation conditions of the beads were optimized by considering the percentage of entrapment efficiency, swelling capacity of the beads, particle size and their release data. In vitro release studies were performed in simulated gastric fluid (pH 1.2) for the initial 2 h, followed by simulated intestinal fluid (pH 7.4) for 4 h. Effects of variables such as, GA concentration, exposure time to GA, drug/polymer (d/p) ratio and percentage of HCl on the release of the IM were investigated. It was observed that, IM release from the beads decreased with increasing GA concentration, exposure time to GA, d/p ratio and percentage of HCl. The highest cumulative IM release obtained at the end of 6 h was 68% for alginate beads which were prepared with 0.5% HCl. On the other hand the least cumulative IM release obtained was to be 20 % for alginate beads which were prepared with 30 min exposure time to GA. In order to understand the crosslinking of the polymeric matrix, the molar mass between crosslinks were calculated using the swelling parameters. It was also found from the swelling experiments that swelling degree of the beads increases with increase in the temperature. The release data have been fitted to an empirical equation to estimate the kinetic parameters. The diffusion coefficient was also calculated for the transport of the drug through the polymeric beads. Values of these parameters were found to be consistent with the release data.

Commercial fibers covered with poly(dimethylsiloxane) were used to pre-concentrate (solid phase microextraction technique) products evolved from the thermal degradation of isotactic polypropylene. Although the analysis by GC-MS indicated the formation of more than one hundred evolved products (ca. forty were identified), only twenty nine formed at 470°C (the temperature of maximum degradation rate for isotactic polypropylene) were analyzed. The main compounds identified were 2,4-dimethyl-1-heptene, 2-methyl-1-pentene, 2,3-dimethyl hexane, n-pentane and 1,3,5-trimethyl cyclohexane. The analysis at 470°C, using different degradation times, also indicated that the compounds 2-methyl-1-pentene and 2,4- dimethyl-1-heptene (major products) were formed at 15 and 25 minutes, respectively. The mechanism proposed for the formation of the major compounds was based on radical formation through chain cleavage (allyl and secondary radicals), followed by a chain decomposition process via hydrogen radical addition or cyclization to a thermodynamically stable six-membered ring.

The enzymatic synthesis of the polyester poly(epsilon-caprolactone) (PCL) were evaluated on the basis of the initial water activity ( a wi) using liquid 1,1,1,2-tetrafluoroethane (R-134a) as solvent media at 2.5 MPa. Polymer yields and molecular weights were directly related to a wi and reaction times. The highest molecular weight ( M n ) was 83,600 gmol -1 , M w / M n 1.4, with a 67% yield after 48 h of reaction with the lowest biocatalyst a wi preparation ( a wi <0.16). It is suggested that the enhanced solubility of the growing polymer chains in liquid R-134a may be responsible for the attainment of such high molecular weight. A maximum polymer yield of 99% with M n 7,246 gmol -1 and M w / M n 4.5 was attained when the biocatalyst was adjusted to a wi =0.22.

Multiwall carbon nanotubes (MWNT) were melt blended at different concentration with linear low density polyethylene (LLDPE). The nanotubes impart the fire-retardant characteristics to the polymer by formation of a thin protective film of MWNT/carbon char generated on the surface of the nanocomposites. The film formation mechanism is discussed

A simple two-steps polymerization method was used to prepare a polyacrylamide hydrogel with a full interpenetrating network structure based on the sorption and porous properties of polyacrylamide superabsorbent. In conditions of 10 g acrylamide monomer, 0.04 g crosslinker for the first polymerization and the second polymerization, respectively, and the swelling ratio of 9, the hydrogel possessed a tensile strength of 1.22 MPa and elongation at break of 900 %.

The present work describes an investigation concerning the acetylation of celluloses extracted from short-life-cycle plant sources ( i.e. sugarcane bagasse and sisal fiber) as well as microcrystalline cellulose. The acetylation was carried out under homogeneous conditions using the solvent system N,N dimethylacetamide/ lithium chloride. The celluloses were characterized, and the characterizations included an evaluation of the amount of hemicellulose present in the materials obtained from lignocellulosics sources (sugarcane and sisal). The amount of LiCl was varied and its influence on the degree of acetate substitution was analyzed. It was found that the solvent system composition and the nature of the cellulose influenced both the state of chain dissolution and the product characteristics. The obtained results demonstrated the importance of developing specific studies on the dissolution process as well as on the derivatization of celluloses from various sources.

The potential of exfoliated graphite nano platelets (xGnP™) as reinforcing fillers in flouroelastomer has been investigated. The dispersion of the nano graphite platelets in the polymer matrix has been investigated by WAXD, SEM, TEM, EPMA and AFM. WAXD studies indicated that the processing of composites did not change the inter-gallery distance (d-spacing) of the graphite platelets. The effect of increasing nano graphite loadings on mechanical properties like tensile strength, modulus and tear resistance has been studied. Formation of weld lines on the fracture surface of the composite has been observed by SEM. The thermal stability was determined using thermogravimetric analysis. The composites showed higher thermal stability in comparison with nonreinforced polymer.

A novel bis-functional reversible addition-fragmentation chain transfer (RAFT) agent bearing triphenylamine (TPA) and bis(indolyl)methane (BIM) groups, {4-[bis(1-carbodithioic acid benzyl ester-indol-3-yl)methyl]phenyl}diphenylamine (BCIMPDPA), was synthesized and successfully used as the RAFT agent to mediate the polymerization of styrene (St). The polymerization results showed that reversible addition-fragmentation chain transfer (RAFT) polymerization of St could be well controlled. The kinetic plot showed it was of first order and the numberaverage molecular weight ( M n(GPC) ) of the polymer measured by GPC increased linearly with monomer conversion, simultaneously, the molecular weight distribution of the polymer was also relatively narrow. In addition, the existence of the TPA and BIM groups in the middle of polymer chain was confirmed by chain extension reaction and 1 H NMR spectrum. The optical properties of the functionalized polystyrene (PS) in chloroform solution were also investigated. Furthermore, the redox process of the RAFT agent and the functionalized PS were studied by cyclic voltammetry method.

The recently developed initiation system, the activator generated by electron transfer (AGET) was used in atom transfer radical polymerization (ATRP) to synthesize well-controlled polyacrylamide in aqueous media at 25°C. The different reducing agents involved ascorbic acid and glucosa; well-controlled polymers were obtained when ascorbic acid was used as water-soluble reducing agent. The polymerizations targeted at degrees of polymerization in the range of 400 resulted in polymers with low polydispersity indices. Moreover, first order plots were linear.

From the results of this study it can be concluded that higher stearic acid concentration as a part of curing activator and high level of curative (i.e. sulfur and accelerator) causes higher crosslink density, tensile strength, modulus and hardness, and lower NBR to nylon-PET cord adhesion. Accelerator type also affects NBR/nylon-PET cord adhesion and using NOBS the highest coating adhesion is achieved. Using semi-efficient vulcanizing (i.e. accelerator/sulfur ratio around 1) is the most suitable way for achieving high NBR/nylon cord adhesion. And finally, independent from accelerator type, sulfur amount and efficiency of vulcanizing system, coating adhesion is a semi-linear function of crosslink density of nitrile rubber.

The aim of this study was to investigate the effect of chain extender and diisocyanate amount on the thermal, mechanical and wettability properties of some polyurethanes. The chain extender nature caused the increase of the thermal stability due to the higher stability of the double and triple bonds respectively in contrast to simple bonds. Tg of the polyurethanes based on PCL/MDI decreased when the unsaturated grade from chain extenders increased. The double and triple bonds content from polyurethane structure was responsible for this behavior. The hard segment contents and the chain extenders nature also influenced the wettability. The results showed that the thermal, mechanical and wettability properties of the final products might be controlled by fine control of the amount of the MDI and the nature of the chain extenders

A new polymer poly{(lactic acid)- co -[(glycolic acid)- alt -(L-lysine)]} (poly[LA- co -(Glc- alt -Lys)]) was synthesized and modified with a cell adhesion peptide, Gly-Arg-Gly-Asp-Tyr (GRGDY, abbreviated as RGD). The process for preparing poly[LA- co -(Glc- alt -Lys)]/RGD involved four steps: Firstly, (3S)-3-[4- (benzyloxycarbonylamino)butyl]morpholine-2,5-dione (BMD) was synthesized by bromoacetyl bromide and N ε -(benzyloxycarbonyl)-L-lysine [L-Lys(Z)]. Secondly, poly{(lactic acid)- co -[(glycolic acid)- alt -( N ε n-benzyloxycarbonyl-L-lysine)]} (poly{LA co -[ Glc- alt -Lys(z)]}) was obtained by copolymerization of D,L-lactide and BMD. Then, poly[LA- co -(Glc- alt -Lys)] was synthesized by catalytic hydrogenation of poly{LA- co -[Glc- alt -Lys(z)]}. Finally, poly[LA- co -(Glc- alt -Lys)] was modified with RGD peptide in the presence of 1,1́-carbonyldiimidazole (CDI). The structures of poly[LA- co -(Glc- alt -Lys)]/RGD and its precursors were characterized by FT-IR, 1 H NMR, 13 C NMR, MS, gel permeation chromatography (GPC), amino acid analysis(AAA). RSC96 cells were used to evaluate the cell affinity of the poly[LA co -( Glc- alt -Lys)]/RGD films and poly(D,L-lactide) (PDLLA ) films. The results of cell culture showed that poly[LA- co -(Glc-alt-Lys)]/RGD was more beneficial to cell adherence and growth than PDLLA.

Fast-swelling porous superabsorbent composites with high water absorbency in 0.9 wt% NaCl solution both at atmospheric pressure and under certain load (p ≈ 2×10 3 pa) were synthesized by a rapid solution polymerization of concentrated sodium acrylate, acrylamide and 2-hydroxypropyl acrylate. The porosity was induced through foaming conducted in the course of polymerization using acetone as porosity generator. The copolymerization and surface morphology of the porous copolymers were characterized by FTIR and SEM. To improve other properties of swollen hydrogel such as strength, resilience and dispersion, the copolymers were modified with inorganic salts after surfacecrosslinking by trihydroxymethyl propane glycidol ether. The influences of various experimental conditions, such as neutralization degree of acrylic acid, amount of initiator and crosslinker on the water absorbent capacity in 0.9 wt% NaCl solution were investigated. The resulting products under optimum conditions possessed the water absorbency of 65 g g -1 and 10 g g -1 in 0.9 wt% NaCl solution at atmosphere pressure and under load, respectively. The results of swelling kinetics measurement in 0.9 wt% NaCl solution showed that the composites had very fast swelling rate (they can reach swelling equilibrium in minutes). In addition, the effect of amount of acetone on swelling rate of the composites was examined in detail. It was shown that appropriate amount of acetone caused products with high porosity, which led to large swelling rate. Moreover, the swollen hydrogel exhibited excellent strength, better resilience and dispersion.

Influence of surfactant structural characteristics on stability of inverse microemulsions of acrylamide-based anionic flocculants (40% (w/w) sodium acrylate and 60% (w/w) acrylamide, based on total amount of comonomers) has been studied by using 17 surfactant blends consisting of two non ionic surfactants with different length of hydrophobic chains, different number of hydrophobic chains per molecule, and with and without double bonds on their hydrophobic chains. Experimental evidence shows that unsaturated emulsifiers are needed for obtaining stable inverse microemulsions of acrylamide-based anionic flocculants and that presence of double bonds on the hydrophobic tails of a surfactant is its major structural characteristic to stabilize this kind of polymeric inverse microemulsions (PIM).

The potential of novel amphiphilic water soluble and degradable poly(ε- caprolactone)- g -poly(L-lysine) as carriers for DNA transfection has been investigated. Two graft copolymers having the same proportion of lysine units but different structures have been synthesized following two grafting techniques. The chemical composition of these copolymers, their expected architectures and their behaviour in aqueous solutions have been studied. The benefits resulting from the use of these degradable polycationic structures as well as their ability to form polyplexes are discussed. Finally, preliminary transfection assays of MCF-7 cells by pRL-TK plasmid using poly(ε-caprolactone)- g -poly(L-lysine) copolymers as carriers are reported.

Efforts to improve dc-conductivity in poly(N-vinylcarbazole) (PVK) are addressed through composites. Such systems included phthalocyanine-based additives with both electronic and ionic character. We present a polysodium- 2,9,16,23-tetramethylamine tetracyclohexanetetrazaporphyrine, acting as the conductive additive in a PVK-binder. A paramagnetic behaviour appears in the additive when heated in the range 70-100°C, which induced further conductivity in the sample. Dc-electrical conductivity was studied for different PVK-additive compositions, in isothermal conditions, using a sandwich Pt/sample/Pt cell. By applying the Poole-Frenkel theory a trapping state was evidenced showing temperature and electric field dependence. An electric field of 9x104V/m establishes a frontier from which the conductivity mechanism is changed. Mobility of charge carriers was calculated according to the Mott-Gurney´s equation

Various concentrations of polypropylene (PP) and polystyrene (PS) blends were prepared with styrene-ethylene/butylene-styrene block copolymer (SEBS) added as a compatibilizer between the two main polymers. We have investigated the effect of SEBS on processing, morphology and thermophysical properties of the blends. The compatibilizing agent improves the blend morphology since smaller particles of the dispersed PS phase in the PP matrix blends are obtained; adding more than 5 % SEBS has no further effect on the blends. The presence of SEBS lowers the crystallinity of the PP-rich phase - as reflected in the enthalpy of fusion and also in the enthalpy of crystallization.

Styrene-ethylene/butylene-styrene (SEBS) block copolymer was used as the compatibilizer for PP + PS blends. We have investigated effects of the presence of SEBS on tribological and mechanical properties; dynamic mechanical analysis (DMA) was also performed. Since the copolymer causes formation of smaller particles of the dispersed PS phase in PP matrix blends, there is improved energy transmission and dissipation resulting in higher impact strength. The SEBS additive is relatively soft and causes a decrease in stress at break but an increase in elongation at break in tensile testing. In most cases the friction of the compatibilized blends is higher although in PS-rich blends we find a decrease. Scratch testing shows a change in wear mechanisms when SEBS is added to PP/PS. In uncompatibilized blends we observe adhesive wear, with crazes formed in the middle of the wear track. A compatibilized blend shows more ductile behavior and ploughing wear.

Plastics produced from the sulfur-based monomer are excellent materials with many optical applications such as ophthalmic lenses, fiber optics and non- linear optics. High refractive index plastic materials are able to reduce the curvature, edge and center thickness of lenses. Sulfur containing plastics such as sulfide, polysulfide, and sulfur containing vinyl compound, thioacrylate, polythiol and isocyanate/isothiocyanate based monomers have demonstrated high refractive index, high Abbe number, good impact strength, excellent machinability, good tintability and good transmittance. In the present article, various sulfur containing plastics with different types of monomers for ophthalmic lens applications are reviewed.

S everal aspects of the melting temperatures ( MT ) of linear chain homologs are discussed. It is shown that with some reasonable modifications of Einstein's model of simple solids, the MT of n -alkanes and their derivatives can be successfully modeled. Results are compared with those obtained by previous authors who have used numerical methods and thermodynamics. Results of investigation of quadratic recurrence relations of the second order and forms including exponential functions are reported. Finally, the correlation of MT with density at T = 298.15 K gives the limiting value, 0.86 gcm -3 , at the temperature of nearly 420 K. It is expected that proper correlations should use densities of liquids just at the MT , because some available data suggest a linear dependence of MT on density. All results obtained are mutually consistent

The migration of di-(2-ethylhexyl) adipate (DEHA), di-(2-ethylhexyl) phthalate (DEHP) and ethylene glycol from PET bottles into the Iranian yogurt drink was studied. According to European Commission regulations acetic acid (3% w/v) was chosen as stimulant. The acetic acid samples were stored at 4, 25 and 45 °C for four months and analyzed periodically by gas chromatography. Differential scanning calorimetry (DSC) was used to investigate if contact with the food stimulant could affect the PET material. It was concluded that the storage temperature had a great effect on the migration of DEHP, DEHA and ethylene glycol. Also increasing storage time resulted in higher concentrations of migrating substances. The concentrations of migrating substances did not exceed their specific migration limit (EEC regulations). Determination of glass transition (Tg) and crystallinity of PET bottles using DSC method showed that the variations in the migration rate of selected contaminants during the time did not relate to the change of PET material in contact with 3% acetic acid.

Polyamide-6 (PA6)/montmorillonite (MMT) nanocomposites were prepared via melt compounding. Maleated acrylonitrile-butadiene-styrene (ABS-g- MA) core-shell structural rubber particles were first introduced to toughen PA6/MMT nanocomposites. Before melt intercalation, MMT was treated with an organic surfactant agent. XRD and TEM results showed that MMT platelets were completely exfoliated in the PA6 matrix. And when the core-shell rubber particles were introduced into the nanocomposites, they were well dispersed in the matrix. Tensile and impact tests showed that a small amount of MMT could increase the yield strength but sacrifice the toughness. However when core-shell rubber particles were added into the nanocomposites, the tensile ductility and impact strength improved greatly. It was reasonable to say that the addition of core-shell particles could make the balance of the stiffness and toughness of nanocomposites.

The determination of the proper rheological behaviour of the polymer melt within micro structured geometry is vital for accurately simulating the micro moulding. The paucity of suitable equipments is one of main hurdles in the investigation of micro melt rheology. In the present study, a measurement system for the melt viscosity of low and high density polyethylene polymer melts flowing through micro-channels was established. The capillary flow model with Rabinowitsch correction was used in the calculations of the viscosity based on the measured pressure drop and volumetric flow rate. The effect of the morphology structure on the viscosity characteristics for both the LDPE and HDPE resins within micro-channels was investigated and discussed. It was found that the measured viscosity values for LDPE and HDPE in the test ranges are significantly lower (about 40~56% and 22~29% for LDPE and HDPE, respectively, flowing through a channel size of 150μm) than those obtained with a traditional capillary rheometer. Moreover, both the percentage reduction in the viscosity value and the ratio of the slip velocity to the mean velocity increase as the micro-channel size decreases. It can be observed that the rheological behaviours of the HDPE and LDPE resins in microscopic scale are different from those in macroscopic scale as a result of the wall slip effect. It also revealed that the wall slip occurs more easily for the LDPE resin within micro channels than HDPE resin due to enlarged effect of morphology structure.

pH and temperature dual responsive hydrogels based on itaconic acid (IA) and N- isopropylacrylamide (NIPAAm) were prepared by means of water and dioxane as mixed solvents. The chemical compositions, structures and morphologies of these hydrogels were characterized by FTIR, TGA and SEM, and their pH and temperature responsive behaviours were investigated through equilibrium swelling ratios, deswelling and reswelling kinetics. The results showed the hydrogels fabricated in this condition had expanded chain conformations and macroporous network structures, and exhibited the larger swelling ratios as well as improved deswelling/reswelling dynamics.

Three types of polystyrenes were prepared at different temperatures of 50, 150 and 250°C by bulk thermal polymerization of styrene below 20 percent of conversion. The assignment of all stereosequences at pentad level of quaternary aromatic carbon and hexad level of methylene carbon of the polystyrenes were done using 13 C Liquid NMR in deuterated chloroform at similar conditions. Bernoullian and first-order Markov statistics were calculated and the results were compared with experimental NMR results. It is shown that first-order Markov statistics fit slightly better than Bernoullian statistics for the assigned carbons. The results indicated that by increasing polymerization temperature the probability of meso addition (Pm) in polystyrene chains was enhanced. P m was calculated for polystyrenes prepared at 50, 150 and 250°C and corresponding values were 0.378, 0.398 and 0.402 respectively. It was shown that by increasing temperature the polymerization is directed toward the Bernoullian propagation. By increasing the NMR acquisition temperature from 20 to 65°C higher resolution especially in quaternary aromatic carbon was achieved and the related peak was splitted to 16 peaks corresponding to a heptad level compared to 10 peaks in 20°C.

The effect of low dose proton irradiation on the morphology of ultra high molecular weight polyethylene (UHMWPE) was studied. The integral proton dose was ranging from 900 Gy to 1200 Gy. The experimental data revealed that low dose proton irradiation in the presence of oxygen leads to the formation of intermolecular crosslinks in UHMWPE and that proton irradiation produces morphological changes that involve a reduction in the thickness of the interfacial region and increase in the thickness of the amorphous region. The observed morphological changes depend on the integral dose

Cellular polymer films are frequently employed for packaging, insulation, and printing. They can also be used as ferroelectrets in transducer applications. Here, we propose a preparation process for cellular polyethylene-naphthalate (PEN) films with the following steps: (1) foaming by means of supercritical carbon dioxide (CO 2 ), (2) controlled inflation through gas diffusion and expansion, and (3) biaxial stretching. We describe and assess the cellular structure that is formed under suitable processing conditions. For foaming, the PEN films are saturated with supercritical CO 2 at room temperature for a few hours, at a pressure as high as 100 bar. The subsequent temperature treatment is very critical for controlling the sample density. Additional inflation can improve the cellular geometry and higher stabilization temperatures during the inflation process cause stronger inflation and thus lower densities. Stretching may be employed in order to achieve a regular cellular structure with lens-like voids. High electromechanical responses, i.e. large piezoelectric thickness coefficients are found only on samples within the proper density range and with optimal cellular structures

The effect of processing variables (filler loadings) and operating variables (frequency) on the impedance and electromagnetic interference shielding effectiveness of vapor grown carbon nanofiber (VGCNF) reinforced chlorobutyl vulcanizates has been investigated. The dispersion and morphology of the VGCNF in the polymer matrix has been studied by scanning electron microscopy and Raman spectra. Addtionally, the utility of EPMA (Electron probe microanalyzer) as a tool to study the dispersion of nano fibers in polymer matrix has been explored for the first time. With increase in frequency and VGCNF loadings the composites showed a decrease in real part of complex impedance for increasing VGCNF loadings whereas the imaginary part showed a slight peak in the range of 9-10 GHz followed by a subsequent decrease. The measured impedance values were plotted as Nyquist plots (Argand diagrams) and a Resistor-Capacitance model was assumed. The EMI shielding effectiveness increased monotonically with filler loading and showed a maximum of around 55 dB at 12 phr loadings, thus making them suitable for EMI shielding applications.

N-Vinyl-2-pyrrolidone (NVP) and maleic anhydride (MA) copolymers were synthesized via radical polymerization. The synthesized copolymers were grafted with methoxypolyethylene glycol (MPEG) chains of different average molecular weights (350, 550, 750 Da). The grafted copolymers were used as surfactants in the synthesis of poly(ε-caprolactone) (PCL) nanoparticles in water by solvent evaporation technique. In order to further test the synthesized surfactants, the miniemulsion polymerization of vinyl acetate was performed. Two methods of obtaining miniemulsion were employed: a sonicator and a static mixer. The synthesized surfactants performed well in both type of experiments while in the case of static mixer nanoparticles with a lower polydispersity were obtained. Droplets with a mean diameter of 250 nm were obtained when using the sonicator while the static mixer led to formation of droplets with a mean diameter of 600 nm.

A series of bismaleimide monomers with various structures were used to prepare poly(aminobismaleimide)s in an attempt to achieve polymers with improved mechanical and thermal properties. Structurally different bismaleimides with ester units and having chlorine substituent at the aromatic ring or hexafluoroisopropylidene(isoprpylidene) group between benzene rings were synthesized by reaction between 3(4)-maleimidobenzoylchloride with various bisphenols. The monomers and polymers were characterized by infrared (FTIR) and proton nuclear magnetic resonance (1H-NMR) spectrometry. Polymers based on these bismaleimides were prepared by Michael addition of diamines to bismaleimides. These polymers exhibited good solubility in N-methylpirrolidone and formed flexible films with good stress-strain properties. The mechanical behaviour of these polymers was investigated by stress-strain measurements on films at room temperature. The influence of the structure of these polymers on their mechanical properties was comparatively studied.

The ever-increasing demand of waterborne heavy-duty coatings for high resistance to many aggressive environment factors and low-surface energy has spurred the ongoing development of acrylic latex modified by fluorine, silicon, and epoxy resin. The morphology of the latex particles were characterized by means of light scattering and transmission electron microscopy (TEM). The stability measurements of modified latex and films showed that the resultant acrylic copolymers containing fluorine, silicon and epoxy resin represented very good resistance to organic solvent, acid and base, water and heat. From contact angle measurements and atomic force microscopy (AFM), a dense and gradient film with surface energy as low as 16.1 mN/m was obtained.

In this paper, the thermal stability and UV-resistant performance of the poly(methyl methacrylate-co-sodium sulfopropyl lauryl maleate-co-2-hydroxy-4-(3- methacryloxy-2-hydroxylpropoxy) benzophenone) /TiO2 (i.e. poly(MMA-co-M12-co- BPMA)/TiO2) composite particles were studied by means of laser diffraction particle size analyzer (LDPSA), thermogravimetric analysis (TGA), ultraviolet-visible absorption spectroscopy (UV-vis), ultraviolet-visible diffuse reflectance spectroscopy (DRS), differential scanning calorimeter (DSC) and weight loss measurements. The results indicate that the dispersion of composite particles is better than that of TiO 2 particles and the thermal stability of composite particles is better than that of poly(MMA-co-M12-co-BPMA). The poly(MMA-co-M12-co- BPMA)/TiO 2 composite particles could absorb more than 90% of UV light in the 210-400 nm wavelength, which was useful to enhance the UV-resistant performance of polymers (e.g. PMMA) . The T g of polymer grafted from the surface of TiO 2 did not change after UV irradiation for 500 h but that of PMMA changed a lot, the weight loss of composite particles was much lower than that of PMMA after UV irradiation, showing that the UV-resistant performance of PMMA has been enhanced by introducing the organic UV-stabilizer BPMA and the inorganic UVstabilizer titanium dioxide into the polymer chains by covalent bonding.

The diamine monomer, 5-amino-2-(p-aminophenyl)benzoxazole(ABO), was successfully synthesized and a series of new naphthalenic sulfonated polyimides (SPIs) were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), 2,2’-benzidinedisulfonic acid (BDSA), ABO and 1,10- diaminedecane (DADE) using one-step high temperature polymerization method. Their structures were characterized by FTIR, 1 HNMR and TG-DSC. The sulfonated degree of the SPI copolymers was controlled through varying the molar ratio of BDSA to the non-sulfonated diamines. Tough and transparent membranes with the typical polyimide brown colour were prepared by casting from the polymer solution. They showed clear anisotropic membrane swelling in water with larger dimensional changes in the thickness direction of membrane. The sulfonated polyimide membrane containing 20mol% benzoxazole moieties (SPI-20) showed desirable thermal stability with the decomposition temperature of 272°C and mechanical stability with the maximum stress of 42 MPa. The proton conductivity (6.2×10 -3 S/cm) of SPI-20 membrane was comparable to that of Nafion ® 117 membrane measured under the same condition (9.8×10 -3 S/cm). The effects of temperature on the proton conductivity, and highly anisotropic proton conductivity in the thickness and plane direction were also investigated.

This Paper deals with the polycondensation between a chiral diacyl chloride (2-(N,N’-pyromelliticdiimido)-bis-propanoic acid chloride (4)) and polyethyleneglycol-diol (PEG-200) and/or three synthetic aromatic diols. The corresponding new PEIs and Co-PEIs which have been obtained in quantitative yields are soluble in polar aprotic solvents, have good thermal stability and optical activity.

The review discusses poly(ester-carbonate)s (PECAs for brief), their production, characterization and their use. Great emphasis is on their production via ester-carbonate exchange and in particular on the copolymer obtained when mixing and heating poly(butylene terephthalate) (PBT for brief) or poly(ethyylene terephthalate) (PET for brief) together with poly(bisphenol A carbonate) (PC for brief). Some notes are added on PECAs with long polyester and /or long polycarbonate blocks and for the case of "transesterification resistant" polymers i.e. when the production of random copolymers via ester-carbonate exchange is impossible under ordinary conditions.

The solvolysis of poly(ethylene terephthalate) from disposed beverage bottles by an aqueous solution of lactic acid, followed by the zinc acetate catalyzed polycondensation of the solvolytic product, yielded a series of aromatic-aliphatic copolyesters containing up to 55 mol.% of incorporated lactic acid structural units. Their molecular parameters were determined using SEC and viscometry. According to DSC, the copolyesters have amorphous structure. Selected copolyester samples were subjected to abiotic hydrolysis at pH 7 and 60 °C. After three days of hydrolysis, the mass of the samples decreased substantially and their molar mass was reduced. At 37 °C, strong degradation of copolyesters by action of the actinomycete Rhodococcus erythropolis was observed. Biodegradability of the copolyesters was confirmed by a composting test. In addition to the changes of the molecular structure of the composed samples, the physical degradation of the foils of the samples tested was also documented by SEM.

Novel microprous beads with the particle size of about 0.6-1.1 mm were prepared for the first time, from methylmethacrylate (MMA), ethyleneglycol dimethacrylate (EGDM), triethoxyvinylsilane (TEVS) and triphenylvinylsilane (TPVS) by suspension polymerization technique. In this study toluene was used as solvent. The swelling measurement results indicate that increasing silicone concentration increases the amount of pores and porosity percent, the weight swelling ratio, and particle sizes, but it has been observed that the apparent density decreases in the case of TEVS, and not in the case of TPVS. Also it has been demonstrated that the volume swelling ratio is independent of TEVS and increases by increasing TPVS concentration. The resulting copolymer beads were characterized by using swelling studies and Fourier transform infrared spectroscopy (FTIR). The morphology of copolymer beads were also investigated by scanning electron microscopy (SEM) and optical microscopy (OM).

Poly(methyl acrylate) (PMA) + SiO 2 composites were synthesized via a sol-gel reaction. The base acrylic copolymers with a content of alkoxysilane groups were prepared by co-polymerization of methylacrylate (MA) with 3-(trimethoxysilyl) propylmethacrylate (3MPS) or vinyltrimethoxysilane (VTMS); the products were cocondensed with tetraethylorthosilicate (TEOS). The PMA + SiO 2 hybrids were characterized. Thermal stability of PMA is enhanced by copolymerization with 3-MPS or VTMS and the presence of SiO 2 ; significant weight loss occurs only above 400°C. Decomposition temperatures are higher by 20 - 25 K as compared to the initial PMA. During the sol-gel process the trimethoxysilyl groups in PMA/3MPS are transformed into a strong silica network. Two different methods of creation of hybrids were used; ESEM shows that only one of them leads to uniform distribution of silica in polymeric matrices.

Twelve new liquid branched poly(methylhydrosiloxanes) of random structures (b-r-PMHS), containing triple branching units MeSiO 1.5 (T), both Me 2 SiO (D) and MeHSiO (DH) chain building units (or only mers MeHSiO), and terminal groups Me 3 SiO 0.5 , have been prepared by hydrolytic polycondensation method of appropriate organic chlorosilanes in diethyl ether medium at temperatures < 0 °C. Two b-r-PMHS containing structural units: M, D, D H , T and T H have been obtained as well. Volatile low molecular weight oligosiloxanes were removed by vacuum distillation at 125-150 °C. Yields of b-r-PMHS ranged from 57 to 84 wt. %. All polymeric products were characterized by FT-IR, 1 H- and 29 Si-NMR, and elemental analysis. Their dynamic viscosities were determined in the Brookfield HBDV+IIcP cone-plate viscometer. The molecular weights of b-r-PMHS and polydispersities of MW were analyzed by size exclusion chromatography (SEC).

Polystyrene fibers were produced by the electrospinning technique. The effects of solution conductivity, surface tension and concentration on morphology and average diameter of electrospun fibers were investigated by scanning electron microscopy (SEM). Solutions of 12, 10, 8, 6% (w/v) polystyrene in dimethylformamide were prepared. Lithium Chloride and a non-ionic surfactant were used to change the conductivity and surface tension of the solutions, respectively. The results indicate that increasing the solution conductivity eliminates the bead formation and increases the fiber diameters. By addition of salt, fine and consistent fibers could be produced from electrospinning of 8% (w/v) PS/DMF solution. Adding 0.1% surfactant reduces the solution surface tension and results in smaller beads and higher fiber diameters. By increasing the amount of surfactant to 0.3%, big beads and thinner fibers are produced.

Emulsion polymerization of octamethyl cyclotetrasiloxane (D 4 ) under microwave irradiation (MI) was studied. The polysiloxane (PSi) nanoparticles via cationic ring-opening polymerization of D 4 were obtained by using the dodecylbenzene sulphonic acid (DBSA), sodium dodecylbenzene sulphate (SDBS) and poly(ethylene glycol) monooctylphenyl ether (OP-10) as the catalyst and the emulsifiers respectively. The particle size analyzer and transmission electron microscope (TEM) were used to determine the particle size of PSi emulsions. The results show that, the particle size of PSi emulsions prepared under MI is substantially smaller and the particle distribution is narrower compared with that under conventional heating (CH). With the aid of MI, the polymerization rate and the equilibrium conversion are enhanced. The polydispersity index (PDI) and molecular weight (M w ) measured by GPC indicate that under MI, PDI of PSi is narrower and M w of PSi at high temperature is lower than those under CH.

The synthesis of modified alkyd resins using a crude tall oil with a content of rosin acids of 39.8 % is described. This material has the composition of fatty acids close to soybean oil, has low cost and is widely available being a forest product industrial residue. The synthetic route includes the reaction of tall oil and maleic anhydride, in the presence of the catalyst (LiOH), followed by polyesterification reaction steps, resulting in an alkyd resin with interesting properties. The acid value (AN) and viscosity were used to follow the reaction, and it appears to be dependent upon the polyalcohol used in the polyesterification step. A period of 15 hours was needed to yield a tack-free coating.

Composites of high density polyethylene with three different amounts of modified boron carbide namely: 7 phr (parts per hundred parts of resin), 15 phr and 24 phr have been prepared. These composites show excellent thermal neutron shielding properties which increase with the increase of boron content in the composites matrix. Moreover, the effects of boron carbide on the mechanical properties, the effect of thermal oxidative aging on mechanical properties and swelling of composites in different solvents have also been studied in these composites.

Polyterthiophene (PTT) thin films have been electrosynthesized using potentiodynamic and potentiostatic methods. The optimal experimental conditions to prepare organic solar cells were determined by deposition of films on platinum and then the process was adapted to an indium tin oxide substrate. Surface morphology of films deposited by potentiostatic methods proved to be more homogeneous than films obtained by potentiodynamic methods. When PTT is employed in photovoltaic cells, the best results are attained using the latter technique. In these solar cells, the polymer is used as electron donor while N,N'- diheptyl-3,4,9,10-perylene-bis-carboximide (PTCDI-C7), deposited by vacuum sublimation, was the electron acceptor. The short circuit current is systematically small, probably due to the roughness of the polymer which induces high series resistance. In any case, it was demonstrated that the electrochemical method is suitable to prepare polymeric layers of electronic devices.

Polymer blends of WRT (waste rubber tire) powder/LLDPE (linear low density polyethylene) have been attempted to prepare thermoplastic elastomers (TPEs). The effects of maleic anhydride-grafted styrene-ethylene-butylene-styrene (SEBS-g-MA) and dicumyl peroxide (DCP) on mechanical, morphological and thermal properties of the blends were evaluated using universal testing machine (UTM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). It was found that combination of SEBS-g-MA and DCP could better enhance the mechanical properties of WRT powder/LLDPE blends compared to SEBS-g-MA or DCP alone. Better compatibility between WRT powder and LLDPE was responsible for the enhancement of mechanical properties, as supported by SEM. The incorporation of SEBS-g-MA and DCP with WRT powder/LLDPE blends reduced the crystallizable perfectness of the blends, but slightly increased the thermal stability of the blends, as shown from DSC and TGA results

In the present study new types of polyurethane-cellulose derivative biomaterials based on urethane prepolymers functionalized with hydroxypropylcellulose are presented. The aim of the present study is to obtain materials with better haemocompatibility, biocompatibility and amphiphilic microphase-separated domain structures. The outcome of remarkable chemical versatility characteristic to polyurethane materials combined with polymers derived from nature like cellulose derivatives resulting in bulk and surface properties is evidenced by means of different techniques like DSC, TGA, FT-IR, AFM and mechanical tensile tests. The influence of various factors on the developed morphologies and the microstructural changes is investigated. Both polyester and polyether macrodiols have been used to prepare these polyurethanes. The aim of this study is to find also alternative methods for improving biostability while maintaining the excellent biocompatibility and other properties.

Due to the interest in the development of low cost membranes with similar capabilities to Nafion®, grafting of styrene on fluorinated polymers by simultaneous irradiation and pre-irradiation methods at high temperature (higher than 50 °C) followed by sulfonation has been a process studied broadly. However, there is very little information about grafting yield at room temperature after simultaneous irradiation. Previous works reported that the surface morphology of the styrene grafts has showed an uneven profile under the studied conditions. This work aims to evaluate the grafting of styrene onto these films after simultaneous irradiation (in post-irradiation condition), using different solvent in periods until 28 days at room temperature. Films of poly(tetrafluoroethylene) (PTFE) and poly(vinylidene fluoride) (PVDF) were immersed in styrene/toluene 1:4 or styrene/methanol 1:4 and then submitted to gamma radiation at 40 and 80 kGy doses. The degree of grafting (DOG) was determined gravimetrically and physical and chemical changes were evaluated by infrared spectroscopic analysis (FTIR), differential scanning calorimeter analysis (DSC), thermogravimetric analysis (TGA), and also by scanning electron microscopy (SEM). For PTFE films, the highest DOG was achieved using toluene as solvent while for PVDF films, the highest DOG was achieved with methanol. Surface images of the grafted films by SEM technique have presented a strong effect of the solvents on the films morphology. Finally, PVDF- g- PS in styrene/methanol film revealed higher DOG, although the surface showed small cavities and discontinuities. On the contrary, the surface of PTFE- g -PS in styrene/toluene presented homogeneous surface.

Polyhydrazides based on furanic diacid chlorides and furanic dihydrazides were prepared. The properties of the products are discussed in terms of the backbone structure and the polycondensation technique employed. Their cyclodehydration was carried out by heating in SOCl 2 to give new polyoxadiazoles consisting of alternating furanic units and 1,3,4-oxadiazole rings.

During processing as well as in service life, polymers degrade. For the majority of polymers this is due to oxidative processes. In this review the mechanism of the thermo-oxidative degradation of the most important (unstabilized) polymers as well as the factors determining the degradation rates are discussed.

We attempted to obtain a novel spongy hydrogel from aqueous Bombyx mori (B. Mori) sericin by using a freeze-thaw method without any cross-linking reagent. The aqueous sericin solution utilized was extracted from silkworm cocoons by using boiling method, and showed continuous molecular weight distribution mainly from 43 kDa to 212 kDa and even higher. To optimize the conditions for hydrogel preparation, the efficiency of hydrogel transformation from sericin solution were investigated by changing sericin concentration, freezing time, freezing temperature and frozen-thawed repetition. The porous characteristics of sericin hydrogel including the porosity, density and maximal water absorbency were performed by changing freezingn conditions. The pore size and morphology of hydrogels prepared at different concentration and freezing temperatures were observed with SEM. FTIR, XRD and DSC curves indicate that the hydrogel prepared at -20 °C and -80 °C adopt mainly random coil conformation.

A novel disilane-containing arylacetylene resin, abbreviated as DSA resin, was synthesized from diethynylbenzene and halogenated disilane by Grignard reaction. The obtained resin was a viscous liquid and soluble in a variety of common solvents. The structures and properties of the resin, cured resin and sintered resin were characterized by FT-IR, 1 H-NMR, DSC, TGA and XRD techniques. The results showed that the DSA resin could cure at temperatures lower than 200°C and the cured resin exhibited high temperature resistance and good ceramic formability.

Surface and electrical properties of two flexible and cross-linked epiclon based polyimide films were investigated. Surface tension measurements indicate an increased hydrophobicity due to both isothermal treatment - which induces imidization and cross-linking - and to the chemical structure, characterized by the different number of ether linkages in the polyimide backbone. Morphology of film surfaces, modified by plasma treatment, shows high roughness and, implicitly, improved adhesion, as required in electronics. The studied polyimides exhibit low dielectric constants and dielectric losses, comparatively to conventional aromatic polyimides. The electrical conductance and resistivity characteristics of these polymers recommend them as good insulators for dielectric layers in microelectronic applications.

A smectic main chain polybibenzoate has been synthesized using a mixture of the branched ether-diols: HO(CH 2 ) 4 OCH(CH 3 )CH 2 OH and HO(CH 2 ) 4 OCH 2 CH(CH 3 )OH, as flexible spacers. The mesophase has been identified as SmCalt by optical microscopy and X-ray diffraction experiments. The irregular chemical structure of the polymer, due to the asymmetry of the spacers, produce two important effects: the mesophase is stabilized and the liquid crystallization is slowed down, making possible the freezing of the amorphous glass by supercooling the isotropic melt. Therefore, both the amorphous glass and the smectic glass can be obtained and analyzed. By differential scanning calorimetric measurements it was found that the glass transition of the mesophase appears at lower temperature than the glass transition of the amorphous state. Depending on the temperature and rate of deformation, the molecular orientation in the drawn smectic phase can be perpendicular (anomalous orientation) or parallel (normal orientation) to the stretching direction (or a mixture of both orientations). The morphology of these oriented samples has been studied by scanning electron microscopy.

The synthesis and potential applications of functional, branched polyethers prepared by cationic ring-opening polymerization is reviewed, mainly on the base of the work from the author’s laboratory. Polymerization of cyclic monomers of ABx type, including highly strained 3- and 4-membered as well as weakly strained 5-membered cyclic ethers substituted with hydroxyl groups is discussed. Cationic polymerization of such monomers proceeds with participation of activated monomer mechanism which leads to the formation of branches. Hydroxy-substituted 4-membered cyclic ethers are highly strained; thus there are no thermodynamic restrictions for their polymerization, but these monomers are not easily available. Thus the possibility of using easily accessible 5-membered hydroxy-substituted cyclic ethers as monomers for cationic ring-opening polymerization was explored in spite of expected thermodynamic limitations due to low ring strain of those monomers. It was found that 5-membered hydroxysubstituted cyclic ethers undergo polymerization; however only low molecular weight products may be obtained from these monomers. It is shown in this review that such products may be useful and some examples of their applications in further synthesis e.g. in the preparation of star polymers and as surface modifying agents in the synthesis of organic/inorganic hybrid materials are described.

In this study, the oxidative polycondensation reaction conditions of 4- [(thien-2-yl-methylene) amino] phenol (4-TMAP) by using oxidants such as air O2, H 2 O 2 and NaOCl were studied in an aqueous alkaline medium between 313 and 363 °K. The structures of the synthesized monomer and oligomer were confirmed by FT-IR, UV-vis, NMR and elemental analysis. The characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of oligo-4-[(thien-2-yl-methylene) amino] phenol (O-4- TMAP) was found to be 36% for air O 2 oxidant, 40% for H 2 O 2 oxidant and 47% for NaOCl oxidant. According to TG analysis, the weight losses of 4-TMAP and O-4- TMAP were found to be 58.11% and 51.38% at 1273°K, respectively. O-4-TMAP was shown higher stability against thermal decomposition. Also, electrical conductivity of the O-4-TMAP was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and electrochemical energy gaps ( ' gE ) of 4- TMAP and O-4-TMAP were found to be -6.13, -6.02; -2.72, -2.69; 3.41 and 3.33 eV, respectively.

The nucleation and growth mechanism (NGM) for the electro-oxidation of 3,4-ethylenedioxythiophene (EDOT) in acetonitrile on platinum and tin(IV) oxide electrodes was determined by analyzing the potentiostatic current-time transients inferred from electrocrystallization theory. The measurements were complemented by using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Preliminary studies performed to establish the working conditions for the potentiostatic technique using cyclic voltammetry (CV) demonstrated that under the working conditions employed herein the best potential scan-rate to obtain electrodeposits of poly(EDOT) was 50 mV·s -1 . The prepared polymer displayed electrochromic properties and p- and n-doping, the p-doping being chemically reversible. In addition, it was observed that the electropolymerization mechanisms on both electrode materials were a combination of two contributions: progressive nucleation, followed by diffusion-controlled tridimensional growth, PN3D dif ; and instantaneous nucleation followed by three-dimensional growth under charge transfer control, IN3D ct . At shorter times, the IN3D ct contribution prevail giving rise to conical deposits, while at longer electrolysis times the polymeric deposit is made of granules, corresponding to the PN3D dif mechanism. The electrode material has no effect at all on the global mechanism, but affects the time at which either contribution predominates. However, the morphological predictions made from the NGMs must be corroborated by other techniques before using the data to control the deposit to be prepared.

2-Sulfonate p -terephthalic acid (sTA) was synthesized, and sulfonated polybenzimidazoles (sPBI) were prepared by direct polycondensation of 3,3’- diaminobenzidine (DAB) and sTA with 4,4’-oxybis(benzoic acid) (OBBA) or 2,2’- bis(4-carboxylphenyl)-hexafluoropropane (BCHFP). Thus the ether groups and hexafluoroisopropylidene units were incorporated into the backbone of the sPBI in order to improve the flexibility and solubility. The sPBI based on OBBA showed poor solubility, while the sPBI containing hexafluoroisopropylidene units were soluble in common solvents. sPBI-20 ~ sPBI-60 could form tough and transparent membranes by solution casting. sPBI indicated high thermal stability, the 5% weight loss temperature (T 5% ) which was higher than 520°C, decreased with the increase of degree of sulfonation. sPBI-20 ~ sPBI-60 showed no glass transition at temperatures lower than 380°C. In addition, sPBI showed low water uptake, low swelling ratio as well as excellent resistance to oxidation. But sPBI exhibited low proton conductivity because of the strong acid-base interactions between basic benzimidazole and sulfonic acid groups.

New telechelic poly(butylene terephthalate) (PBT) ionomers, characterized by the presence of some aliphatic sulfonated chain ends, were prepared by reaction with the 1,4-butane sultone. Two methods of synthesis were compared and the final polymers, containing different percentages of ionic groups, were characterized, with particular attention to the thermal properties. Thermogravimetric analysis shows that the presence of ionic groups does not modify the thermal stability of PBT. The differential scanning calorimetry indicates that the crystalline phase and the crystallinity degree of PBT do not change in the presence of ionic chain ends, whereas the crystallization rate was found to be strongly modified. The ionomers crystallize at very high rate, due to the nucleating effect of the ionic aggregations formed in the melt.

Dielectric spectroscopy is a powerful method that allows the study of dynamics of polymers in a wide frequency range. In this work, the state of clay dispersion was related to the dielectric properties of the polymer nanocomposites based on organoclay filled maleated polypropylene (PPgMA). Fully and partially exfoliated samples were prepared through powered sonication and melt blending, respectively. Though two mechanical relaxations were revealed from dynamical mechanical analysis (DMA), only a single high-temperature process resulting from interfacial polarization was observed in broadband dielectric measurements. Dielectric dispersion parameters that appear sensitive to clay loading and degree of exfoliation were identified. The nanomorphology was primarily reflected in the Maxwell-Wagner characteristic relaxation frequency value, fp, where samples with higher degree of exfoliation showed lower relaxation rate. The relaxation time constant, which is the reciprocal of 2πfp, can be correlated with mean distance of clay layer separation in the nanocomposites and therefore provides additional information on exfoliation of clay platelets. A clear evolution of the relaxation activation energy with the degree of clay dispersion was also observed. The experimental results indicated that sonicated samples with fully exfoliated clay platelets yielded the longer relaxation time and the higher activation energy compared to their partially exfoliated counterparts.

N,N’-Diphenyl glutaramide (DPG) is found to be an effective nucleating agent to induce the β-form of iPP. The results of wide angle X-ray diffraction, differential scanning calorimetry and polarized light microscopy indicate that 0.2 wt% of DPG can induce the maximum amount of β-form iPP, and the favorable crystallization temperature for the growth of β-form is 120 ˚C in this study. Analysis of the misfit factor between the cell parameters of DPG and β-iPP shows β-iPP can epitaxially crystallize on the bc face of DPG crystal well.

Electrical conduction characteristics in two different polyimide films prepared by the imidization of polyamic acid (PAA) and pre-imidized polyimide (PI) solution were investigated. It is found that the current density of the polyimide film from PAA was higher than that of the polyimide film from PI at the same electric field, even though the conduction mechanism in both polyimide films follows the ionic hopping model. The hopping distance was calculated to be 2.8 nm for PAA type and 3.2 nm for PI type polyimide film. It is also found that the decay rate of the residual electrostatic charges on the polyimide films becomes faster in the PAA type than in the PI type polyimide film.

P hase behavior in the blend of -SO3H terminated polystyrene (PSS) with poly( n -butyl acrylate-co- N,N -dimethylaminoethyl methacrylate) containing 6.0 mol% N,N -dimethylaminoethyl methacrylate (P1) is investigated by optical microscopy and small-angle X-ray scattering (SAXS). Comparing the miscibility of polystyrene/P1 blend, it is confirmed that the miscibility of the PSS/P1 blend is drastically improved by the hydrogen bonds between -SO 3 H and tertiary amino group. In addition, two-phase region of the PSS/P1 blend is split into two regions around the stoichiometric composition, in which the molar ratio of -SO 3 H to tertiary amino group is 1:1 stoichiometry. SAXS result shows that the PSS/P1 blend at stoichiometric composition forms a block copolymer-like aggregate and it takes a disorder state.

Nanocomposites of poly(4-methyl-1-pentene) (PMP) with various weight fractions of multiwall carbon nanotubes (MWNT’s) were prepared by melt compounding. The nanocomposites are characterized for structure using scanning electron microscopy. The viscoelastic behavior of the nanocomposites is investigated in solid as well as melt state. The study reveals a significant increase in storage modulus especially in the rubbery regime of the polymer matrix and reduced tan δ. Rheological properties in melt show that the complex viscosity and shear storage modulus are increased as a result of incorporation of MWNT. A systematic decrease in the cross over frequency is noted which is attributed to the increased relaxation time. In dielectric analysis, composition dependent enhanced permittivity and conductivity are observed. The thermal stability of the polymer is found to be significantly improved in presence of MWNT’s.

Acrylic fibers are the major precursor of carbon fibers. In this work, the synergistic effect of polymer concentration and jet stretching on porosity, morphology and mechanical properties of wet-spun poly(acrylonitrile) fibers were studied and then the role of void size was elucidated. The results showed that the effect of jet stretching on fiber porosity is negligible below a threshold polymer concentration. Increasing polymer concentration up to 20 vol. % reduced the total porosity significantly but increased the nanometric void population slightly. On the other hand increasing polymer concentration and jet stretching simultaneously, improved mechanical properties as a result of a remarkable reduction in porosity. In addition, stretching shifted nanovoids distribution strongly toward smaller sizes. This was attributed to the effect of stretching and increasing polymer concentration on reducing the diffusion coefficient. Young's modulus of fibers also increased with decreasing overall porosity. Finally, strength-diameter correlation showed a good agreement with the Griffith's theory.

Four new poly(aryl ether sulfone)s containing naphthalene rings were synthesized from 1,5- and 2,7-bis-(4-fluorosulfonyl)naphthalene isomers with different diphenols. These polymers exhibited high glass transition temperatures and good thermal stability. The glass transition temperatures ranged from 220 to 236°C and the 5% weight-loss temperatures were above 423°C. As the four polymers were treated at 300°C, the glass transition temperatures of polymer series a obviously increased and the polymers became insoluble in common organic solvents including NMP, DMAc, and chloroform, etc., but the series b did not, which indicate that a thermal crosslinking reaction via free radicals happened leading to crosslinked polymers

In this work, poly(3-ethylenedioxythiophene) (PEDOT) was synthesized on glass by spin coating for 10 seconds at 500 rpm and polymerization was carried out in an oven at 110°C for 10 min. Methanol and water mixture were used as the solvent and dodecylbenzene sulfonic acid (DBSA) as the surfactant. The conductivities of films were measured and their relationship with different solvent or various surfactant contents were discussed. The morphology of films was observed by SEM, and PEDOT synthesized in methanol-rich solvents or with less DBSA content had more smooth surfaces, showed lower degradation temperature (by TGA). Also, PEDOT synthesized in methanol-rich solvents or with less DBSA were doped better, as observed by UV-Vis spectra.

The polymerizations of n -butyl methylacrylate ( n BMA) were carried out using bis( β -ketoamino)nickel(II) complexes (Ni[CH 3 C(O)CHC(NR)CH 3 ] 2 : R = phenyl, 1 ; R = naphthyl, 2 ) in combination with methylaluminoxane (MAO) in toluene. The effect of parameters such as polymerization temperature, Al/Ni molar ratios, polymerization time, and monomer concentration, on catalytic polymerization activity and polymer molecular weights, were examined in detail. Both of the nickel(II) catalytic systems exhibited moderate activity, and produced P( n BMA) with high molecular weight and relatively broad molecular weight distribution (M w /M n =2.0~3.0. The obtained polymer has been characterized by means of FTIR, 1H NMR, 13 C NMR, DSC, and WAXD technique and was confirmed to be syndio-rich stereospecific P( n BMA).

The Influence of electron beam on behaviors of high density polyethylene/poly(ethylene glycol)/organoclay nanocomposites has been studied. Nanocomposite compounds were prepared by melt intercalation method. X-ray diffraction (XRD) and transition electron microscopy (TEM) revealed the combination of nanocomposite morphology. Thermal and mechanical properties of nanocomposites were studied by using Thermogravimetric analysis (TGA), Young's modulus, tensile strength and hardness tests. The results show that at 500 KGy dose of irradiation the Young’s modulus and tensile strength values have been enhanced in comparison with pure blend by cross-linking and the surface hardness of samples raises by increasing the clay content The samples with the clay content of 5 wt% in the matrix with 500KGy dose of irradiation have shown satisfactory thermal resistance. The irradiation at high levels has degraded the nanocomposites and an optimum dose must be employed to enhance their properties. The presence of poly(ethylene glycol) as a compatibilizer has improved the dispersion of clay layers into the matrix and has enhanced the mechanical properties and thermal resistance of nanocomposites. The presence of the clay in the matrix has increased the adsorption amount of xylene and toluene into the bulk of nanocomposites and the irradiation has decreased this capacity by the dose level.

The Avrami equation has been extensively used to describe the polymer crystallization kinetics. Evaluation of kinetic parameters of this equation is quite troublesome, calling for properly predetermining induction time. To avoid this problem, an analytical approach in terms of differential scanning calorimetry exotherm maximum point was adopted here so as to conveniently estimate the Avrami equation kinetic parameters both in isothermal and dynamic crystallization mode. In the case of dynamic crystallization under isokinetic conditions, a modified version of the Avrami model by Nakamura was employed and adequate predictions based on the derived formulas were obtained. However, due to the simplified assumptions of the Avrami theory, our adopted relations are only applicable to earlier stages of crystallization process and do not account for secondary crystallization.

A series of novel fluorinated poly(ether imide)s (PEIs) IVa-h were synthesized from 4,4’-(2,5-tolylenedioxy)diphthalic anhydride ( I ) and various trifluoromethyl-substituted aromatic bis(ether amine)s ( IIa-h ) via a conventional two-step method with thermal or chemical imidization of the precursor poly(amic acid)s. These PEIs were readily soluble in a variety of organic solvents; they were soluble with a concentration higher than 10% in amide-type polar solvents, ether type solvents, and chlorinated hydrocarbons. The solution-cast films showed a high optical transparency and low color intensity, with an ultraviolet-visible absorption edge of 371- 377 nm and low b* values (a yellowness index) of 4.9-7.5. These films were strong and tough with tensile strength of 90-103 MPa. They exhibited glass-transition temperatures ( T g ) in the range of 207-293 o C, with 10% weight loss temperature in excess of 500 o C in air or nitrogen atmosphere. They also showed low-dielectric constants (2.95-3.37 at 1 MHz) and low moisture absorption (0.20- 0.67 wt %).

The solid phase FTIR spectra of (z)-4-(2-(acryloyloxy)ethoxy)-4-oxobut- 2-enoic acid ( cis- AEOEA) and its polymers have been recorded in the regions 3500~500 cm -1 , respectively. The IR spectra of cis-AEOEA was interpreted with the aid of normal coordinated analysis following full structure optimization and force field calculation based on density functional theory (DFT). Standard scaling factor was used to afford better correspondence between the calculated and experimental wavenumbers for the separation and unambiguous identification of observed IR spectra of cis -AEOEA, especially for C=C double bonds. The characteristic absorption bands of C=C are used for identifying the kind of C=C double bonds in cis -AEOEA’s polymers.

Three azobenzene-based dithiocarbamates, 2-(phenylazo-phenoxycarbonyl) prop-2-yl 9H-carbazole-9-carbodithioate (APCDT), 2-(4-nitro-phenylazophenoxy- carbonyl)prop-2-yl 9H-carbazole-9-carbodithioate (ANPCDT), 2-(4-cyanophenylazo- phenoxy-carbonyl)pro-2-yl 9H-carbazole-9-carbodithioate (ACPCDT), were synthesized and used as RAFT agents in the polymerizations of styrene (St) and methyl methacrylate (MMA). The results showed that APCDT, ACPCDT and ANPCDT were effective RAFT agents for the polymerization of St. In the case of MMA, the polymerization showed hybrid behavior. The different substitutes on azobenzene moiety in dithiocarbamates did not show obvious influence on the controllability of the polymerizations. The UV and fluorescence spectra of RAFT agents and obtained azobenzene-terminated polymers were investigated

Depolymerization of poly(ethylene-terephthalate) (PET) in PET/HDPE blends, obtained from virgin polymers during mechanical recycling was studied. Extrusion of PET/HDPE blends was simulation of the first cycle of recycling and extrusion of the blends with EPDM/HDPE (E-M) masterbatch and HDPE/EPDM (PEM) masterbatch the second cycle. After that the samples were additionally treated to examine their thermooxidative stability. Blends were characterized by determination of the concentration of carboxyl groups by Pohl titration, by FTIR spectroscopy and differential scanning calorimetry (DSC) to determine crystallization (T c ) and melting (T m ) temperatures. The concentration of determinated carboxyl end groups in blends indicate presence of formed polymer radicals with hydroxyl-carboxyl end groups as the result of depolymerization of PET. Presence of characteristic groups was also confirmed by FTIR. DSC results indicate the influence of HDPE on crystallization temperature of PET and points to the fact that even degraded samples maintain the chemical structure of PET. From the results it can be seen that addition of the particular modifier can reduce and even prevent the depolymerization during the recycling process.

Amphiphilic diblock copolymer poly(methyl methacrylate)- b -poly(acrylic acid) (PMMA- b -PAA) was prepared by 1,1-diphenylethene (DPE) method. Firstly, free radical polymerization of methyl methacrylate was carried out with AIBN as initiator in the presence of DPE, giving a DPE-containing PMMA precursor with controlled molecular weight. tert -Butyl acrylate ( t BA) was then polymerized in the presence of the PMMA precursor, and PMMA -b- P t BA diblock copolymer with controlled molecular weight was prepared. Finally, amphiphilic diblock copolymer PMMA- b -PAA was obtained by hydrolysis of PMMA- b -P t BA. The formation of PMMA- b -PAA was confirmed by 1 H NMR spectrum and gel permeation chromatography. Transmission electron microscopy and dynamic light scattering were used to detect the self-assembly behavior of the amphiphilic diblock polymers in methanol.

To obtain molecularly imprinted polymers capable of selective rebinding with nicotinamide (NAM), NAM imprinted polymers were synthesized via bulk polymerization using various functional monomers and cross-linkers. The NAM recognition properties of these polymers were investigated in organic and aqueous solvents by equilibrium rebinding experiments. The results show that the imprinted polymer prepared using 1:4:4 molar ratio of NAM/MAA/TRIM in dichloromethane exhibited the greatest NAM binding capacity and selectivity. This polymer is potentially valuable for the analysis of NAM in complex matrices where selective isolation and identification are needed.

Biodegradable films of methoxy poly(ethylene glycol)- b -poly(DL-lactide co - glycolide- co -ε-caprolactone) diblock copolymers (MPEG- b -PDLLGCL) were prepared by solution casting method. Effects of MPEG block length and DLL:G:CL ratio of the MPEG- b -PDLLGCL films on their mechanical properties and hydrolytic degradation were studied and discussed. It was found that the mechanical properties of films were strongly dependent on glass transition temperatures (Tg) of the diblock copolymers. The hydrolytic degradation was investigated in phosphatebuffered solution at 37°C. The degraded films were characterized using gravimetry (%water uptake and %weight loss), 1H-NMR spectroscopy, differential scanning calorimetry and size exclusion chromatography. The %weight loss of the degraded films increased and molecular weight decreased on increasing the MPEG block length and incorporating the G and CL units, according to their %water uptakes. The MPEG content of the degraded film decreased and the Tg increased with hydrolytic degradation time.

Antimicrobial packaging is one of the most promising active packaging systems. Antimicrobial packaging is the packaging system that is able to kill or inhibit spoilage and pathogenic microorganisms that are contaminating foods. A tremendous effort has been made over the last decade to develop and test films with antimicrobial properties to improve food safety and shelf life. For food preservation, chitosan films are very effective. Chitosan has widely been used in antimicrobial films, to provide edible protective coating, dipping and spraying for the food products due to its antimicrobial properties. Chitosan can be formed into fibers, films, gels, sponges, beads or nanoparticles. Chitosan films have been used as a packaging material for the quality preservation of a variety of food. Chitosan has great potential for a wide range of applications due to its biodegradability, biocompatibility, antimicrobial activity, non-toxicity and versatile chemical and physical properties. The present review outlines the preparation and antimicrobial activity of chitosan based films.

Well-defined cleavable poly(styrene-block-ethylene oxide) polymers were prepared by living anioinc polymerization, using cumyl potassium as the initiator. These polymers contained an acid cleavable moiety, such as diphenyl methyl or anthracenyl methyl ether linkage, between polystyrene and poly ethylene oxide block. Atomic force microscopy (AFM) studies on the thin films illustrate the formation of nanoporous architecture due to acid cleavage of the polyethylene oxide fraction.

A novel cucurbit[6]uril (CB[6]) mediated alginate physical hydrogel bead was prepared for the first time, which is based on the electrostatic attraction and ion-dipole interaction between sodium alginate and CB[6]. These alginate/CB[6] gel beads are useful in controlled drug delivery and other biomedical applications. The potential of alginate/CB[6] gel beads as carrier for 5-Fluorouracil (5-Fu) was studied in this paper. The properties of alginate/CB[6] gel beads were studied by FT-IR, XRD and TGA. The process of the formation of alginate/CB[6] gel beads was recorded by Digital cameras. The external morphology of the dried beads were observed using SEM. Alginate/CB[6] gel beads first was formed as a thin film on the surface of the alginate solution droplet, holding its spherical shape. The color of the alginate/CB[6] gel beads changed from almost colorless to white with the increase of gel time, and also the beads became small and compact. The dried alginate/CB[6] gel beads were about 900-1000 μm, irregular spherical and the surface of dried beads showed a corrugated surface having a uniform distribution of regular nodules and cavities.

Poly(methyl methacrylate-acrylic acid-ethylene glycol dimethacrylate) copolymer particles abbreviated as P(MMA-AA-EGDM) copolymer particles were prepared by soap-free emulsion copolymerization. The concentration of carboxyl group on/near the surface of particles increased with the increase in acrylic acid (AA) content in the recipe. The carboxyl groups were reacted with amine nucleophiles such ethylene diamine and 1,6-diaminohexane through preactivation with dicyclohexyl carbodiimide as a coupling agent. The modified particles were characterized by electron micrographs and FTIR spectral analysis. Adsorption behaviours of some biomolecules were measured to have idea about=-0 the polarity of the particles surface

Highly toughened super high-impact polystyrene (HIPS)/organophilic montmorillonite (Org-MMT) nanocomposite was prepared by solution blending method. Organophilic modification of MMT layered silicate was achieved by using a special toughener-intercalant, quaternary ammonium salt of α-tertiary amine functionalized polybutadiene and shown by X-ray diffraction analysis. The resulting HIPS/Org-MMT nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), and static and dynamic mechanical analyses. The morphological study of HIPS/Org-MMT nanocomposite showed that nanolayers were exfoliated in nanocomposite and moreover caused much more well dispersed and reduced PS occluded rubber domains. This mechanism was found to be responsible for dramatic increase in toughness of nanocomposites. Additionally, improved thermal and dynamic mechanical properties of the resultant nanocomposite promises to open a new way for highly toughened super HIPSs via nanocomposite assemblies even with a very low degree of clay loading.

Nanofibers could provide benefits due to high surface area for biomaterial scaffolds. In order to improve both silk fibroin and gelatin performance for potential biomedical applications, in this article the electrospinning of silk fibroin (SF)/gelatin (GT) blends with different composition ratio and concentration was performed with formic acid as a spinning solvent. The nanofibers morphologies and diameters were observed by Scanning electron microscopy (SEM). Blending with GT could improve the viscosity and spinnability of spinning solution. As-spun SF/GT blend nanofibers were more homogeneous and non-beaded than pure SF nanofibers. The diameter decreased with higher voltage at same electric field intensity. On increasing the concentrations of spinning solution, the pore diameter of nanofibers decreased, and the porosity increased. In addition, FTIR and DTA analyses showed SF/GT nanofibers had more β-sheets than pure SF nanofibers, which may be caused by an intermolecular interaction between SF and GT. Blending with GT also led to substantial enhancement in mechanical properties of SF nanofibers.

Composites of polypropylene (PP) with mica powder were produced by melt mixing in an internal mixer. In this research work, the effect of the interfacial modifiers such as maleated polypropylene (MAPP) and silane coupling agent, that encapsulated the mica (treated mica), on the mechanical, thermal and rheological characteristics of mica-filled PP have been investigated. In the literature, it can be seen that increasing mica powder leads to reduced crystallinity of PP. But our results show that reduction in crystallinity is noticeably lesser when interfacial modifier such as MAPP is used. Also, the results of thermogravimetric analysis test showed that MAPP and treated mica caused improvement of heat resistance of the composites. The degradation shifted to higher temperatures which could be due to adhesion between PP and mica powder. The mica powder when added to PP increased the viscosity considerably. However treated mica/PP composite in molten state had noticeably less viscosity in comparison with that of neat micafilled PP and thus having better moldability. Results of decrease in elongation at break with filler content have been compared with predictions of Nielsen’s model and Mitsuishi equation.

Macromolecularly imprinted calcium phosphate/polyacrylate/alginate (CP/PA/A) multi-hybrid polymer microspheres with the surface and embedded imprinting of bovine serum albumin were prepared with sodium alginate (SA), (NH 4 ) 2 HPO 4 and sodium polyacrylate (SPA) by using CaCl 2 as gelling agent in inverse-phase suspension. Infrared spectrum analysis demonstrated that multihybrid components were produced in the microspheres. Rebinding dynamic of both imprinted microspheres proved a higher BSA rebinding relative to those nonimprinted ones. The specific surface area of CP/PA/A microspheres increased when compared with non-imprinted ones. The specific rebinding peak and imprinting efficiency cross point have appeared in rebinding dynamic curves, which showed remarkable difference in rebinding behaviours between surface and embedding imprinted microspheres.

Development of descriptive models for thermally-driven gelation process for methyl cellulose (MC) solutions is presented in this paper. The available heat absorption profiles obtained using a micro-differential scanning calorimeter (μDSC) during the gelation of MC (SM4000) aqueous solutions with various concentrations were examined. Different mathematical models were considered for fitting the experimental data. Necessary constants for the proposed mathematical formulations were obtained based on the DSC measurements to achieve the most promising fit. Further, analysis based on the mathematical models was performed to describe influence of various parameters for the gelation process, including the total heat, the degree, and the state of gelation. The effect of variations in MC concentrations on these parameters was investigated and the possible mechanisms were highlighted. Proposition was made towards the existence of a water entrapment point on the degree of gelation plots of MC hydrogels and its significance was discussed. Abstract Development of descriptive models for thermally-driven gelation process for methyl cellulose (MC) solutions is presented in this paper. The available heat absorption profiles obtained using a micro-differential scanning calorimeter (μDSC) during the gelation of MC (SM4000) aqueous solutions with various concentrations were examined. Different mathematical models were considered for fitting the experimental data. Necessary constants for the proposed mathematical formulations were obtained based on the DSC measurements to achieve the most promising fit. Further, analysis based on the mathematical models was performed to describe influence of various parameters for the gelation process, including the total heat, the degree, and the state of gelation. The effect of variations in MC concentrations on these parameters was investigated and the possible mechanisms were highlighted. Proposition was made towards the existence of a water entrapment point on the degree of gelation plots of MC hydrogels and its significance was discussed.

Magnetic iron oxide (maghemite, Fe3O4) particles were encapsulated with polyester resin. The resulting magnetic powders were characterized by Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), Fritsch particle sizer, scanning electron microscopy (SEM), X-ray diffractometer (XRD) and vibrating sample magnetometer (VSM) measurements. FTIR and XRD confirmed the presence of iron oxide in polymer phase. The TGA and DSC measurements indicated the magnetic polymer particles have more than 50% iron oxide content and high thermal stability. SEM revealed that all maghemite particles were embedded in the polymer phase. The size distribution analysis of prepared magnetic particles has shown that the mean diameter of the bare iron oxide particles slightly increased with encapsulation. According to our magnetometry data, shape of the loops evidences the ferromagnetic character of the material and no evidence of superparamagnetism was seen.

In the field of polymer nanocomposite materials, carbon nanotubes have attracted lots of research interests in the recent past for their potentialities in improving a wide range of polymer properties. We present here a comprehensive study on polypropylene/carbon nanotube composites evaluating the morphology as well as the thermal behaviour of the prepared systems. Pristine as well as -COOH functionalised carbon nanotubes were taken into account and melt mixed at different weight fractions with PP; the crystallisation characteristics of the material were evaluated by means of DSC and XRD and the thermal behaviour was assessed through TGA analyses. The nanotubes appear to affect significantly the properties of the matrix in a way notably dependent on the functionalization and on the filler amount.

In present work, the effect of novel blocked mercaptosilane(3- propionylthio-1-propyltrimethoxylsilane) (called hereafter PXT) on structure and dynamic mechanical properties of natural rubber/silica (NR/silica) composites was studied in efficient, semi-efficient and conventional vulcanization systems. Equilibrium swelling method investigation indicates that PXT is able to enhance crosslinking density of composites. The investigation of properties shows that PXT can strengthen the reinforcement of silica for NR vulcanizates and substantially enhance the resistance to flex cracking and abrasion of NR/silica composites. Since PXT possess two functionally active end groups which can chemically react with both silica and rubber, at 2 phr of the PXT content, NR/silica composites possess optimum comprehensive dynamic mechanical properties.

Vinyl ester resins are unsaturated polyesters, widely used as matrix for high performance composite materials. The paper presents the synthesis and characterization of some vinyl ester resin/hydroxyapatite bioactive compositions using an unsaturated copolyester based on turpentine oil as reactive diluent. The vinyl ester oligomer /unsaturated copolyester/hydroxyapatite structural complex was characterized from the morphological point of view, water absorbtion, density measurements and volume contraction. The water uptake is dependent on the concentration in vinyl ester resin. The increase of the vinyl ester resin content in the bioactive composite leads to the increase of the density, respectively to a significant decrease of the volume contraction

Polyaniline (PANI) nanofibers were prepared using an organic solution of aniline as seed in aqueous solution of ammonium persulfate oxidant. Two types of organic solvents were used, which are miscible and immiscible with water to investigate their effect on the properties of the resulting PANI via the aid of SEM, UV-Vis and FT-IR spectra and conductivity measurements The water dispersity of the polymer was also discussed based on the UV-Vis spectra data. Two possible mechanisms were proposed to explain the formation of the PANI nanofibers during the seed polymerization.

Ethylene-vinyl alcohol (EVOH) copolymers with different vinyl alcohol (VOH) mole % have been grafted by the carboxyl terminated poly(butyl acrylate) (PBA) prepolymers by the grafting-onto method. The carboxyl terminated PBA were synthesised by solution radical polymerization using 4,4 azobis(cyanovaleric acid) (ACVA) as initiator and thioglycolic acid (TGA) as matched chain transfer agent and then converting carboxyl groups into acid chloride terminated prepolymer by reacting with oxalyl chloride. The acid chloride terminated prepolymers were reacted with EVOH copolymer backbone to synthesize graft copolymers. The graft copolymers were characterized by the Size Exclusion Chromatography (SEC), Fourier Transfer Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. Results from these analyses confirmed the grafting of PBA side chain on to EVOH backbone. Differential Scanning Calorimetery (DSC), Dynamic Mechanical Thermal Analysis (DMTA) and x-ray diffraction studies of graft copolymers showed that the morphology of crystalline EVOH polymers has been disrupted due to grafting of amorphous PBA chains.

Rapid phthaloylation and succinylation of wheat straw hemicelluloses with phthaloyl dichloride (PdC) and succinyl chloride (SC) in N,N dimethylformamide/ lithium chloride (DMF/LiCl) system using N -bromosuccinimide (NBS) as a catalyst was achieved for only 5 minutes at 50 °C by microwave irradiation. The degree of substitution (DS) ranged between 0.43 and 1.47. The effect of the molar ratios of xylose units in hemicelluloses to phthaloyl dichloride or succinyl chloride on the degree of substitution was investigated. It was found that the reactivity of succinyl chloride was higher as compared to Phthaloyl dichloride under similar experimental conditions. 13 C NMR studies revealed that the esterification occurred at the C-3 and C-2 positions in the β-D-xylose units of hemicelluloses, but preferentially at C-3 position. However, it should be noted that microwave irradiation did result in more degradation of the macromolecular hemicelluloses than conventional heating technique as shown by a lower thermal stability of the hemicellulosic derivatives obtained by microwave irradiation than those obtained by conventional heating technique.

PBT sheets were extruded from T-die using a single extruder and were winded by a take-up roller controlled at 50°C and with speed at 1.2 m/min. Oriented PBT sheets were prepared with various winding roll speeds at 3.6, 4.8 and 6.0 m/min. Fine structure and physical properties of PBT sheets thus obtained were investigated by measuring the molecular orientation, crystal structure, dynamic visco-elasticity, thermal and mechanical properties, sonic modulus, etc. PBT melts were found to be readily crystallizable in the sheet. In the case of roll drawing, the DR max of PBT sheet was 5. The PBT sheets prepared from winding speed at 6 m/min showed polymorphism of both α- and β-form crystallites with crystallinity of about 24%. In the tri-directional WAXD patterns, the PBT sheets by the roll drawing method turned out to be oriented in the uniplanar-axial form. For the roll drawn PBT sheets with various winding speeds, large orientation effects were observed in the winding direction together with improved thermal and mechanical properties.

Electromechanical properties of crosslinked polydimethylsiloxane (PDMS) and PDMS_PEDOT/PSS blends were investigated as potential actuator materials. Experiments were carried out under the oscillatory shear mode and with applied electric filed strength varying from 0 to 2 kV/mm. The storage modulus, G', of the crosslinked PDMS increases with increasing electric filed strength with a scaling behavior: ΔG' α E α where the scaling exponent α is equal to 0.88. With PEDOT/PSS particles added at volume fractions of 5, 10, 15, and 20 vol%, the storage modulus G' of the polymer blends, are higher than that of the pristine crosslinked PDMS. The scaling exponent of the scaling behavior decreases from 0.88 to 0.10 as the volume fraction increases from 0 to 20 vol%. The storage modulus sensitivity,, attains maximum values of 8%, 9%, 10%, and 9%, at particle volume fractions of 5, 10, 15, and 20 vol%, respectively at the electric field strength of 2 kV/mm. Temporal response of the crosslinked PDMS system is irreversible, but the response of the PDMS_PEDOT/PSS system is evidently reversible

The electrospinning process of Poly-L-lactide (PLA) solutions using liquid reservoir collectors was studied. As collector liquids, distilled water and sodium chloride solutions of different concentrations were used. A new, non-linear correlation of the fiber diameter and the filling of the collector was found. It was also proved, that the electrical conductivity of the substrate has a strong influence on the electrospinning process and the nanofibers obtained therein, both in diameter and in morphology

Four kinds of novel polymerizable benzophenone (BP) photoinitiators MBP, BMBP, MPBP, BMPBP containing functional maleimide groups, were used as free radical photoinitiators with N-methyldiethanolamine (MDEA) as coinitiator (H donor). Such photoredox systems were studied by means of ESR spectra. The results show that all the four photoinitiators possess the same initiation mechanism as BP/MDEA system; meanwhile, two kinds of radicals were observed as the excited triplet of the photoinitiators can abstract hydrogen from the methylene groups or the methyl groups of MDEA. The photopolymerization of three monomers with different functionality, methyl methacrylate (MMA), 1,6-hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate (TMPTA), initiated by these four polymerizable photoinitiators, was studied through dilatometer and photo- DSC. The results show that different photoinitiators behave differently towards monomers: MPBP system is the most efficient for all the three monomers; BMPBP is the least efficient for MMA, and BMBP is the least efficient for HDDA and TMPTA. The efficiency of the photopolymerization is greatly affected by maleimide groups and different vinyl monomers.

The influence of annealing on the microstructure and molecular orientation, thermal behaviour and mechanical properties of uniaxially drawn iPP thin film was studied by wide-angle X-ray diffraction, differential scanning calorimetry and tensile testing, respectively. The correlations of mechanical and microstructural properties of annealed films were also examined. The transformation of smectic phase of iPP to the α-form was more pronounced with increasing annealing time and temperature. The true and apparent crystallinities and crystal thickness were strongly enhanced with annealing time and temperature. The relative molecular orientation tended to increase with annealing time. These results caused the significant improvement of modulus and tensile strength of the annealed films in both machine (MD) and transverse (TD) directions. The increases in MD-Young’s modulus and MD-tensile strength were well correlated with the increase in true crystallinity obtained in equatorial scans. Some relationship between the increase in crystal thickness and the increase in Young’s modulus in both MD and TD directions was also found.

In this paper, cerium oxide hollow nanospheres have been prepared via a polymer-monomer self-assembly route; it may be possible to extend this approach to fabricate other metal oxide hollow nanospheres. In this method, cerium oxide hollow nanospheres were fabricated by calcining hollow polymer spheres which were prepared via addition of ceric ammonium nitrate (CAN) into self-assembled micelles which were prepared through dissolving chitosan (CS) in methacrylic acid (MAA) solution.

The simulation of controlled/living radical copolymerization (CRcP) is conducted using the method of Monte Carlo. Target Markov chains are obtained by calculating transfer probabilities instantly. The statistical results which are all the functions of conversion are obtained, including cumulative composition, segment length distribution, dyad and triad concentrations. The effect of reaction parameters on gradient structures is investigated, including initiation rates, monomer feed ratio and reactivity ratios. The results show that reactivity ratios, monomer feed ratio and conversion are more important parameters that can affect gradient structure than initiation rates. Initiation rates can cause difference in sequence structures at early stage of copolymerization and affect cumulative compositions continuously to a moderate degree. Monomer feed ratio mainly affects the fore-head of gradient copolymers while conversion simply affects the rear-end of gradient copolymers. The results of segment length distribution show that with the increase of difference in reactivity ratios, the distribution changes from Flory distribution which indicates random structure to Poisson distribution which indicates block composition

Synthesis of latexes based on polystyrene (PSt) and polybutylacrylate (PBuA) dyed with Rhodamine B (RhB), by polymerization in ternary microemulsions, is discussed in this paper. Silica was generated through the solgel process of methacryloxypropyl-trimethoxysilane (MPTS) and glycidyloxypropyltrimethoxysilane (GMPS). MPTS copolymerizes, through its double bounds, with St or BuA. GMPS can form covalent bonds with RhB by opening of the oxyranic cycle. The smallest average diameter of the particles was obtained for latexes prepared with MPTS+GMPS couple. Latexes with RhB prepared in the presence of an organophilic layered silicate (Cloisite 20 A) were used for comparing the influence of the inorganic fillers on microemulsion properties. By St and BuA copolymerization with MPTS hybrids which can react by sol-gel process with GMPS, a coupling agent for RhB, were prepared. By using RhB as molecular sample, polarity modifications for polymer-inorganic latexes were put in evidence.

We investigated the influence of loading two different types of organoclay on the linear viscoelastic properties of an uncured epoxy nanocomposite coating. Meanwhile, the effect of sonication in the dispersion process on the characteristics of nanocomposite has been studied. To achieve fully dispersed structures of clay-epoxy, we applied high shear mixing and high-intensity ultrasound during the synthesis of clay-epoxy nanocomposites.The flow properties of the compositions with clay loadings more than 4 wt% of low CEC quaternary ammonium modified clay, as analyzed by rheomechanical spectroscopy (RMS), showed a solid-like behavior. While the neat resin system exhibited Newtonian flow, some nanodispersed coatings exhibited pseudo plastic flow behavior, typical of polymeric fluids such as gels and pastes. With varying the type of the clay the resultant coatings exhibited a storage modulus ranging from 0.01 to over 400 Pa and a loss modulus ranging from 4 to over 200 Pa. Moreover, the complex viscosity was ranging from 12 to 1100 Pas as the clay loading increased from 0 to 8wt %. The strong increase in modulus of one type of the clays was due to the mainly intercalated and dispersed silicate platelets. The increase rate in storage modulus of these compositions decreased at higher organoclay loadings and was not linear. These results can lead to the prediction of film formation properties and application conditions of these nanocomposite coatings

Low molecular wieght 1,2-polybutadiene (Aldrich) tacticity was determined by 13 CNMR (100.6 MHz). It was found that the olefinic methylene carbon has the highest splitting and a combination of pentad and heptad sequences was determined which is in agreement with the theoretical calculations. For the first time aliphatic methine carbon assignment of 1,2-polybutadiene was performed. Furthermore, olefinic methine carbon assignment was also performed and the results were compared with the theoretical calculations. For all carbons Bernoullian and first-order Markov-chain propagation statistics were used to fit the experimental data and a good agreement was obtained indicating an atactic polymer (P m = 0.467). It was shown that the most probable reaction before gelation which happens by heating the polymer under vacuum at 250°C, is crosslinking accompanied with methyl group formation. The decrease in double bond intensity of the pendant group together with constant cis and trans double bond intensities were observed. During heating the syndiotactic triad sequences are consumed indicating that no cyclization has happened.

Ternary high-density polyethylene/polystyrene/carbon nanofiber nano composites were fabricated by melt-compounding. The effect of melt compounding sequences on electrical conducting behavior of such composites was examined. Two compounding sequences were adopted in this study. Route I consisted of an initial melt mixing of HDPE and PS, followed by blending with CNFs. Route II involved an initial formation of the PS/CNF master batch, followed by blending with HDPE. The results showed that CNFs were dispersed in HDPE phase of Route I prepared HDPE/PS/CNF nanocomposites whilst they resided in PS phase of Route II formed nanocomposites. Electrical measurement showed that Route II prepared nanocomposites had a low percolation concentration of 1.1 vol% CNF.

The tensile behavior of low density polyethylene/polydimethylsiloxane immiscible blends was investigated with respect to morphological variation of the blends. Experimental data of elastic modulus was compared with theoretical predictions of parallel model (mixing rule), as the upper bound of modulus, Halpin- Tsai model, and a two-parameter equivalent mechanical model proposed by Kolarik, which takes into account the continuity of minor phase. As the predictions of these models were not in good quantitative agreement with experiment, some modifications were made to the Kolarik model. Furthermore, a new approach for determining equivalent mechanical model parameters was proposed based on the calculation of phase continuity parameters as a function of composition. Using this approach, the values predicted for elastic modulus were found to be in good agreement with the experimental data. Moreover, the influence of a peroxide curing agent on the tensile properties of the blends was studied. The improvement of the tensile properties of the blends could have resulted from two contributions: the effect of curing reaction on the tensile properties of constituents and the better interfacial adhesion, because of possible interfacial reaction, as indicated by morphological observation.

The amphiphilic block copolymer polystyrene- b -poly( N,N diethylacrylamide- co - N,N -dimethylacrylamide) (PSt- b -P(DEA- co -DMA)) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of DEA and DMA using PSt as macro chain transfer agent (PSt CTA) and N , N -azobisisobutyronitrile (AIBN) as initiator. Polymeric micelles were prepared by dialysis of the block copolymer solution in tetrahydrofuran (THF) against aqueous media. The polymeric micelles PM73 based on block copolymer P73, which was prepared with molar ratio DEA/DMA/PSt CTA/AIBN = 700:300:10:1, exhibited a lower critical solution temperature (39.2°C) in aqueous solution which was a little higher than the human body temperature. Polymeric micelles PM73 showed a unimodal size distribution with an average diameter of 24.2±0.5 nm. The micelles were thermodynamically stable in aqueous media above the critical micelle concentration (1 mg/l). The anti-inflammation drug, prednisone acetate, was incorporated into PM73 as the model drug. The loading capacity was found to be around 8 wt%, and the drug-loaded micelles showed similar size distribution patterns (monodisperse with an average diameter of 32.1±0.5 nm) and morphology (spherical) to the empty micelles. The drug-loaded micelles showed remarkable thermoresponsive drug release behavior, in response to the micellar structural change.

A new polyphosphazene which bears o-acetylphenoxide group [NP(o- C 6 H 4 -COCH 3 )]n, PAOP was synthesized. PAOP can be efficiently thermally crosslinked at mild condition using p-phthalaldehyde as cross-linker and sodium hydroxide as catalyst both in solution and solid reaction. It was found that solid reaction gives more products with carbon-carbon double bond. The suggested process of cross-linking reaction was described based on the progress of small molecular reaction. Influence factors of cross-linking reaction including water and temperature were also discussed and it was concluded that water prevents crosslinking and higher temperature causes higher percent conversion. The photochemical reaction of cross-linked PAOP was simply studied using UV and it was demonstrated that carbon-carbon double bond decayed under UV irradiation and more complicated products were obtained.

The phase structure, crystallization and melting behavior of high density polyethylene (HDPE) blends with hydrogenated petroleum resin P-100 were investigated by polarized optical microscopy (POM), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Results of polarized optical microscopy and scanning electron microscopy indicated that the structures of blends had a three-dimensional bi-continuous network. The network sizes depended on the blends composition and crystallization conditions, when the blends were quenched or cooled down slowly below the melting temperature of HDPE from molten state; the network sizes decreased with both the increasing of HDPE content and the decreasing of the quenching temperature. Differential scanning calorimeter analysis revealed that the melting point and crystallization temperature of HDPE in blends shifted to lower temperature with the decreasing of HDPE concentrations. The depression of HDPE melting point and crystallization temperature in blends were attributed to the smaller sizes of HDPE crystallites in presence of petroleum resin. The activation energy values and nucleation activity values indicated HDPE had lower crystallization activation energy and P-100 acted as a more effective nucleating agent only at low HDPE concentration

By anionic ring opening polymerization initiated by cyclodextrin oxyanions generated from NaH and β-cyclodextrin(β-CD), novel biodegradable β- CD cored star-shaped poly(ε-caprolactone)s (s-PCLs) were synthesized and then characterized by means of FTIR, GPC, 1 H-NMR. The effects of different feed molar ratios of NaH and β-CD on arm number and on the molecular weight of s-PCLs, and the relationship between the polymerization time and monomer conversion were investigated. Moreover, the physical properties of linear PCL (l-PCL) and s- PCLs with similar molecular weights but different arm number were studied and compared by DSC, SEM and intrinsic viscosity measurement, respectively. It was found that the feed molar ratio of NaH and β-CD is an important factor which influences both the molecular weight and arm number. The melting points and intrinsic viscosities of s-PCLs with similar molecular weights were lower than that of l-PCL, and were found to decrease with increasing arm number. Both SEM and AFM showed that the surface morphology of s-PCL films was different from that of l-PCL. These results indicated that s-PCL with different arms and physical properties could be synthesized using just a β-CD core by adjusting the feed molar ratio of NaH and β-CD

Surface modification of the metal is a critical procedure for gene therapy on the metal implants, such as stent and artificial joint. Polycations can condense with DNA by self-assembly, form polyplexes spontaneously as a result of electrostatic interactions and protect DNA from degradation by DNase. The ability of chitosan, polyethyleneimine (PEI), and poly(amidoamine) (PAMAM) dendrimers to condense plasmid DNA(pDNA) was determined by electrophoresis, X-ray photoelectron spectroscopy (XPS) and surface plasmon resonance (SPR). Polycation’s attachment of pDNA to the metal surface was confirmed by XPS which showed no phosphorus peaks on the interface showing the protective effect on pDNA from DNase degradation. Polycations with higher molecular weight or hyperbranched or dendrimer structures can fulfill many of the requirements for effective gene protection from DNase degradation. Chitosan with higher molecular weight (>= 200 kDa) has superior efficiency to protect pDNA against DNase degradation on the surface of the gold chip. Hyperbranched PEIs and PAMAM dendrimers, even with lower molecular weight (for example, 20kDa for PEI, 50kDa for G5) can protect pDNA against DNase degradation. The results of this study present a platform for further optimization studies of polycation-based gene delivery systems.

The stability of core-shell particles (CSPs) with butyl acrylate (BA) as the core and methyl methacrylate (MMA)/glycidyl methacrylate (GMA) mixture in various compositions as the shell was investigated by turbidity measurements. The experiments demonstrate that lower amount addition of GMA could not improve the latex stability. When the amount of GMA exceeded 2% of the total reactants, it began to improve the stability of the latex. With the increasing content of GMA, the latex became more and more stable. On the other hand, experimental data also show that the stability was improved by increasing the concentration of sodium dodecyl sulfate (SDS).

Encapsulation of silica nanoparticles was performed by emulsion copolymerization of methyl methacrylate (MMA) and styrene (St) using dimethylaminoethyl methacrylate (DM) as an auxiliary monomer. The emulsion polymerization was performed in the presence of silica nanoparticles as the seed to obtain encapsulated silica nanoparticles with polymer content and average particle sizes ranged from 35 wt. % to 85 wt. % and 114 to 272 nm respectively. Electrostatic attraction between anionic surface of silica beads and cationic amino groups of DM is the main driving force for the encapsulation of the silica nanoparticles. The influence of MMA, St and DM concentration on the coating of the silica nanoparticles was studied. It was demonstrated that DM has an important role in stabilizing the system. Transmission electron microscopy showed that coreshell structures with silica particles as core were coated with the polymer, of which the amount and morphology were influenced by the total monomer concentration and molar ratio of MMA to St. Zeta potential measurement confirmed the presence of DM on the surface of composite particles. Thermogravimetric analysis showed that the incorporation of silica in polymer matrix results in an enhancement of thermal stability in the encapsulated products. Differential scanning calorimetry studies indicated that the glass transition temperature of encapsulated particles can be either higher or lower than those of the pure terpolymer counterpart, depending on the DM content of the polymer shell. The products were also characterized by FT-IR spectroscopy.

The antimicrobial activity against E. coli , St. aureus and A. niger of zinc oxide when blended with polymers has been measured by an applied dynamic method. Two polymers: poly(amide) 6 (PA6) and low density poly(ethylene) (LDPE) have been used as matrix. ZnO nanoparticles content as low as 1% w/w in the polymers showed great antibacterial activity but no antifungal activity. The results of bacterial slaying capability of these nanocomposites was also found to be better when zinc oxide was dispersed in PA6, where the efficiency is similar to pure ZnO particles. The composites have been investigated by means of scanning electron microscope (SEM) and differential scanning calorimeter (DSC).

A novel copolymer as a macromonomer with a polyethylene glycol (PEG) unit as the phase change element and a vinyl group was synthesized for the preparation of polymeric solid-solid phase change materials. The IR, 1 HNMR, DSC and WAXD and POM were employed to determine the structure and properties of the novel monomer. The results show that the novel monomer possess steady molecular structure, excellent crystal properties, higher phase change enthalpy and reactivity. Furthermore, the novel polymeric solid-solid phase change material was also prepared via the copolymerization of the novel copolymer macromonomer and styrene. The phase change properties of the polymeric solid-solid phase change material were characterized.

Halloysite nanotubes (HNTs) were utilized to prepare polypropylene (PP) nanocomposites by simple melt-compounding approach. Compared with other silicates such as montmorillonite and kaolinite, HNTs show much better dispersion property. The PP nanocomposites with HNTs exhibit concurrence increase in tensile and flexural strength, flexural modulus and impact toughness. Surface modification of HNTs lends the PP nanocomposites higher strength, modulus and lower toughness. The increase in mechanical properties is correlated with the well dispersion of the high aspect ratio HNTs and the orientation of HNTs in PP matrix. Morphology studies show that HNTs can be dispersed in PP uniformly at lower HNTs loading and excessive loading of HNTs causes a little aggregation. Surface modification of HNTs can alleviate the aggregation effectively. The storage modulus of the nanocomposites increases consistently with the HNTs concentration. The surface modification is beneficial to the further improvement in storage modulus. Similar to other silicates, HNTs facilitate the crystallization of PP due to the heterogeneous nucleation

The study presents a procedure to acquire a colloidal silver-based antimicrobial polymer composition. Carboxymethylstarch (CMS) as polymer matrix, and colloidal silver particles (Ag 0 ) obtained by in situ synthesis with silver nitrate and sodium citrate as reducing agent, were used. In solution, the presence of COOH and OH groups in carboxymethylstarch directs to silver complexation and acquirement of a stable suspension of silver particles. Due to the presence of colloidal silver particles, the composition presents bacteriostatic activity and in association with some drugs (acetylsalicylic acid or diclofenac sodium) pharmaceutical compositions can be obtained, which are useful in the prevention and treatment of some infections or diseases. The compositions were characterized by FTIR spectroscopy, UV-vis spectrophotometry, particle size analysis and zeta potential measurements. Drug release tests were done in vitro in phosphate buffer solution (pH=7.4, at 37°C).

Depolymerization and monomer recovery from polycarbonate (PC) by methanolysis was investigated. Methanolysis with molar ratios of methanol to polycarbonate ranging from 12.5 to 50 was carried out from 170°C to 300°C for up to 30 min. Polycarbonate decomposed into two monomers, bisphenol A (BPA) and dimethyl carbonate (DMC), and two useful by-products, phenol and 4-tertbutylphenol. The percentage depolymerization of polycarbonate increased markedly from 170°C to 230°C and decomposed completely when the temperature was higher than 260°C. Reaction time and molar ratio of MeOH/PC are two other important factors that affect polycarbonate methanolysis. The optimal depolymerization condition of PC was found at 240°C with the molar ratio of MeOH/PC equal to 37.5 and the time of 5 min. Under these conditions, polycarbonate would decompose completely and the monomer recovery of BPA and DMC were 90.7% and 95.2%, respectively.

Both ester- and ether- based thermoplastic polyurethane (TPU) nanocomposites were prepared by melt blending, using 3 wt % Cloisite 10A (organically modified montmorillonite clay) as the nanoscale reinforcement. The nanocomposites were subsequently melt-blended with polypropylene (PP) using maleic anhydride grafted polypropylene (MA-g-PP) as a compatibilizer (in the ratio of 70/30- TPU nano/PP, 70/25/5-TPU nano/PP/MA-g-PP). Besides giving substantial increase in modulus, tensile strength and other properties organoclay reinforcement functions as a surface modifier for TPU hard segment. X-ray diffraction studies revealed that compatibilization is further improved by introducing functionalized PP (MA-g-PP) in the organoclay containing blends. The blend system was evaluated by DSC, DMA, SEM, mechanical properties and Xray diffraction. The results indicate that the ester- TPU exhibited greater miscibility than ether-TPU. Abrasion resistance and water absorption were also better for compatibilised ester- TPU blends as compared to the ether-TPU materials.

The curing behavior of the epoxy/dicyandiamide/2-methylimidazole system in the presence of montmorillonite clays intercalated with different compounds are analyzed by Fourier transform infrared spectroscopy (FTIR) and with differential scanning calorimetry (DSC). The properties of intercalated clays were analyzed by X-ray diffraction and thermal gravimetric analysis (TGA) and it was obtained that the d-spacing of different intercalated clays follows the order of the siloxane-clay>org-clay>epoxy resin-clay>pristine clay; this trend is consistent with the amount of intercalated chemicals obtained from TGA. The results of FTIR and DSC indicate that the curing exotherms, curing rates, formed functional groups, and curing mechanisms (reaction order) of the epoxy resin system are affected by the curing temperature and the type of intercalated clay used because of the stoichiometric imbalance of reactive groups resulted from the mutual diffusion of epoxy resin constituents and intercalated chemicals. The curing heats of the epoxy resins with different clays are in the order of the epoxy resin-clay> siloxane-clay>org-clay. It is shown that the Kamal model when applied can correctly describe the curing kinetics of the studied epoxy resin/clay systems at 160 and 170°C.

A novel superabsorbent composite simultaneously incorporated with both attapulgite and Na-montmorillonite was prepared by aqueous polymerization using N,N’ -methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. The effects of the clay content on swelling ability of the superabsorbent composite were investigated. The superabsorbent composite were characterized by IR, XRD and SEM. The results indicate that Na-montmorillonite was exfoliated in the composite, whereas, attapulgite kept its crystalline structure. The content of clay has great influence on surface morphology and water absorbency of the superabsorbent composite, and the collaborative effect of attapulgite and Namontmorillonite on swelling ability is superior to that of single one.

A comb like phase change material (PCM) CDA-IPDI-MPEG, based on cellulose diacetate (CDA) as a backbone, with methoxy polyethylene glycol (MPEG) grafted onto it, was synthesized by a two-step reaction in the presence of dibutyltin dilaurate (DBTDL) catalyst system, using acetone as solvent and isophorone diisocyanate (IPDI) as crosslinking reagent. Size exclusion chromatography (SEC) was used to characterize the molecular weight distribution of each step reaction products. Back titration was utilized for determination of free isocyanate. The molecular structures were confirmed qualitatively using FTIR and H1-NMR measurements. Phase change properties were characterized by differential scanning calorimetry (DSC).

Chemical modification of poly(vinylacetylene) (PVacet) was performed through click reactions by which alkyl and fluoroalkyl groups were introduced to the pendent terminal alkynes of PVacet. Novel polymers containing 1,2,3-triazoles were consequently obtained and their structures and properties were characterized by FT-IR, 1 H NMR, TGA, DSC and GPC. The polymers modified by alkyl groups had good solubility, thermal stability and reasonable molecular weights. It was also demonstrated that the properties of fluorine-containing polymers were affected by fluorine atoms with hydrophobic and chemical proof properties

Star- and brush-polysiloxanes were synthesized via living radical polymerization using two different catalytic systems. The new compounds were characterized by 1 H-NMR, gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) techniques. CuCl and 2,2’-bipyridyl proved to be the most efficient catalytic system. The type of catalytic system and the reaction conditions control the number of arms for star polymers or the grafted-chain density for brush polymers. The use of chloromethyl styrene as monomer or co-monomer yields homogeneous star- or brush-polysiloxanes, although chloromethyl styrene is an inimer system. The homogeneity of materials was verified by GPC and DSC (TOPEM) methods. For linear grafted polysiloxanes the molecular simulations reflect a tendency of chains to adopt globular conformation for high values of the branching density. The polysiloxanes grafted with styrene/chloromethyl styrene were modified with azobenzene in order to obtain systems able to react to the light stimuli. Rheological behavior of the polymer solutions were evaluated before and after irradiation with UV light. After the UV irradiation a significant viscosity increase was evidenced

Oppositely charged natural polyelectrolyte Heparin (HS) and chitosan (CS) were immobilized on the surface of poly(ε-caprolactone) (PCL) by a layer-bylayer (LBL) self-assembly procedure. Positively charged poly(allylamine hydrochloride) (PAH) was used as the first layer onto the surface of PCL. Then negatively charged HS and positively charged CS were deposited in a LBL assembly manner. The effect of this surface modification method was evaluated by ATR-FTIR spectroscopy and static contact angle measurements. The anticoagulant activity of modified PCL was evaluated using full human blood. The modified PCL samples showed prolonged activated partial thromboplastin time (APTT), prothrombin time (PT) and thromboplastin time (TT) compared with neat PCL. Scanning electron microscopy (SEM) indicated that adhered platelets retained their natural, round morphology on the modified PCL surface. The cytocompatibility of the HS/CS surface modified PCL sample was evaluated with pig iliac arteries endothelial cells (PIECs). The proliferation of the cells cultured on modified PCL films was better than those on neat PCL films.

The effect of incubation period and the presence of organic membrane on eggshell activity toward elastomers (NBR, NR and SBR) has been investigated. After hatching eggshell (AHES) showed enhanced mechanical properties when compared to before hatching eggshell (BHES) and calcium carbonate. Compounds containing BHES powder also showed good mechanical properties. Both types of eggshells reduced optimum curing time of the compounds. This trend was more considerable in NBR compound. The improvement of mechanical properties of the compounds attributed to elemental composition and higher specific area of AHES. The results of this study showed both before hatching and after hatching eggshell can be used in elastomeric compound as a bio-filler

Vulcanization of polymer by ultraviolet irradiation has been playing an important role in the industrial sector especially for coating, ink and printing applications. Polymers used in this area are sensitive to ultraviolet (UV) radiation. Their final products have properties required for particular specifications. One of the methods to synthesize ultraviolet-sensitive polymers is the grafting of ultraviolet-sensitive units onto other polymer backbones. In this work, styreneisoprene- styrene copolymer (SIS) was selected as a polymer backbone whilst acrylic acid served as an ultraviolet sensitiser. The grafting reaction was carried out in a solution state of toluene through the ring-opening addition reaction of epoxidized SIS molecules. The results indicated that acrylic acid can be successfully grafted onto a previously epoxidized SIS backbone at a reaction temperature of 100°C. Furthermore, the acrylation yield increased with the increase of reaction time.

Novel pH sensitive carboxymethyl (CM) chitosan/acrylic acid hydrogels were prepared. CM-chitosan and acrylic acid (AA) in aqueous solution were copolymerized and crosslinked by using vinyltriethoxysilane (VTESi). Different amounts of AA and crosslinker were incorporated in CM-chitosan/AA hydrogel. IR analysis confirmed the presence of pyranose ring as well as Si-O-Si linkage within the hydrogel. Thermogravimetric analysis showed an increase in the stability of hydrogel either having high AA ratio or high crosslinker ratio. The swelling of the hydrogels was carried out by investigating the effect of time, pH (buffered and nonbuffered) and ionic media. In non-buffered media the overall swelling was found to be high as compared to buffered media. Maximum swelling was observed in hydrogel having mass ratio of 7.0 (AA : CM-chitosan). This hydrogel showed low swelling in low pH similar to that of the stomach and high swelling in neutral pH similar to that of the small intestine and can be used in drug delivery applications

The four kinds of TiCl 4 /MgCl 2 type supported Ziegler-Natta catalysts, Cat-1, Cat-2, Cat-3 and Cat-4, were prepared by reaction of MgCl 2 -ethanol adduct with TiCl 4 . Cat-1 contains no internal electron donor (ID), Cat-2 contains diethyl phthalate (DEP) as ID, Cat-3 contains anisole as ID, and Cat-4 contains both DEP and anisole as ID. Ethylene copolymerizations with 1-hexene by these catalysts were compared. Influences of the internal electron donor on catalyst activity, copolymer composition, composition distribution, molecular weight and molecular weight distribution were investigated. Cat-3 showed the largest ability of incorporating 1-hexene into copolymer chains among the four catalysts. Each copolymer sample was fractionated into two fractions: fraction soluble in boiling n heptane (HS) and fraction insoluble in boiling n-heptane (HI). 1-Hexene content of the HS fraction is 6~10 times of that in the HI fractions. Amount of the HS fraction of copolymer by Cat-2 and Cat-4 was much lower than that of Cat-1 and Cat-3. Introduction of internal donor to the catalysts, especially diethyl phthalate (DEP), increased the blockiness of HI fractions. The molecular weight of both fractions increased when there is ID in the catalyst. Addition of anisole reduced the difference in molecular weight between HS fraction and HI fraction, but addition of PA enlarged the difference. The results are discussed based on a mechanistic model of MgCl 2 -supported Ziegler-Natta catalysts.

The solution polymerization of ε-caprolactone (CLO) initiated with stannous 2-ethylhexanoate has been studied in the temperature range 90 - 150 °C. ε-Caprolactam (CLA) was used as a solvent. Although relatively high polymerization temperature was used poly(ε-caprolactone) (PCLO) was formed solely and no CLA structural units were incorporated into its chains. The polymerization rate increased with CLO content in feed and polymerization temperature. A linear dependence of molar mass on yield of PCLO indicates living character of polymerization. When polymerization was carried out in the presence of organically modified MMT, nanocomposites PCLO - layered silicate with an exfoliated structure were obtained

UV-VIS investigations on polycarbonate irradiated with accelerated U ions are reported. The experimental data are consistent with the decrease of the energy gap due to irradiation and indicate the formation of isolated conjugated structures. The relatively weak decrease of the energy gap and the shape of the electron spin resonance lines indicate that the conjugated structures are isolated within the polymeric matrix

Controlled radical polymerization of styrene was initiated using N methyl- 2-pyrrolidone (NM2P) and 1-dodecanethiol (1DT). This polymerization system exhibited “living” characteristics, namely the molecular weight averages of resulting polymers increased linearly with conversion, which has been determined by gel permeation chromatography (GPC) analysis. The polymer was additionally characterized with Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance ( 1 H NMR) spectroscopy. Kinetics of controlled radical polymerization has been studied and the temperature dependency of overall polymerization rate constant has been determined. A comparison of conventional bulk radical and controlled bulk radical polymerization of styrene has been explored. Conventional radical polymerization was initiated with 2,2’-azobis(2- methylpropionitrile) (AIBN), whereas 1-dodecanethiol was applied as a chain transfer agent. The reaction rate of controlled radical polymerization was slower than the reaction rate of conventional radical polymerization initiated with AIBN. Consequentially, the activation energy and the pre-exponential factor were lower in the case of controlled polymerization in comparison to the ones observed in the conventional - AIBN initiated - system. Furthermore, by comparing the controlled to the conventional radical polymerization lower polydispersities were observed. Macromolecular structure analysis suggested a more linear chain structure in the controlled radical polymerization system. The thermal properties of polymer products have also been studied and the corresponding glass transition temperatures were higher upon comparison of the conventional and the AIBN initiated system, respectively

A hydrogel from acrylic acid and hydroxypropyl cellulose was made. The percentages of raw materials and crosslinkers were varied and its swelling behavior was evaluated. Some of the gels obtained absorbed more than 300% wt. The gels with higher swelling percentages were characterized by means of IR spectroscopy, differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA), and scanning electron microscopy (SEM). The FTIR showed the presence of the main reactants in the gel, while the DSC showed a phase separation in the gel. This gel is partly biodegradable because of the content of hydroxypropyl cellulose and has the viscoelastic properties of poly(acrylic acid).

A novel conjugated polynitrile thin film, plasma-polymerized 3- quinolinecarbonitrile (PP3QCN) thin film was prepared by plasma polymerization of 3-quinolinecarbonitrile. Fourier transform infrared (FT-IR), Ultraviolet-visible spectroscopy (UV-Vis), and X-ray photoelectron spectroscopy (XPS) studies revealed that extensively conjugated C=N double bonds were formed in the deposited plasma film and the plasma polymerization of 3-quinolinecarbonitrile took place mainly through the opening of the π bonds of C ≡ N functional group under our experimental conditions. Plasma-polymerized 3-quinolinecarbonitrile thin film shows a blue emission with relatively high photoluminescence (PL) intensity at about 475 nm wavelength. The fabricated devices with PP3QCN as electroluminescent layer sandwiched between Indium Tin Oxides (ITO) and aluminium (Al) were also found to show a blue emission.

This paper presents the characterization of poly(aniline) (PANI) and poly(methyl methacrylate) (PMMA) coatings obtained by mixing PANI with PMMA aqueous dispersions (latex particles). These dispersions were characterized by using dynamic light scattering for sizing, zeta-potential analysis and thermal analysis. PMMA and PANI/PMMA dispersions show negative charged particles with zeta potential greater than |40| mV, a zeta-average diameter of 64 nm for pure PMMA and a bi-modal particle-size distribution centered at 45 and 120 nm for a mixture with 25% w/w of PANI. Films obtained by casting were characterized by using scanning electron microscopy and they show a conductivity increase upon PANI content reaching a value of 1 mS cm -1 for a film with 25% w/w of PANI. In addition, Raman spectroscopy have shown the presence of the conducting form of PANI in the films and cyclic voltammetry experiments corroborated that they are electroactive in both acid and neutral solutions.

A new, highly efficient and very simple method for the synthesis of pure octahedral methylsilsesquioxanes (CH 3 SiO 3/2 ) 8 , from cyclic 2,4,6,8-tetraalkoxy- 2,4,6,8-tetramethylsiloxane, was developed. We have found that T 8 Me can be synthesized from a mixture of alkoxymethylcyclosiloxane isomers in the hydrolytic condensation process, utilizing an ionic catalyst - tetrabutylammonium fluoride (TBAF). The reaction was carried out under very mild conditions, at room temperature, in a variety of solvents of different polarity. A substantial solvent effect was observed. THF helped in the formation of pure T 8 Me , whereas in other solvents mixtures of T 8 Me and poly(methylsilsesquioxanes) (PMQS) of substantial degree of regularity, were obtained.

The microstructure of melt-processed, immiscible poly(2,6-dimethyl-1,4- phenylene ether)/poly(styrene-co-acrylonitrile) blends (PPE/SAN) was controlled by systematically adjusting the viscosity ratio between both phases. For this purpose, low-viscous polystyrene (PS) was added as a third component, as it shows selective miscibility with PPE and thus allows the varying of the shear viscosity of PPE over a broad range. In order to theoretically predict the phase morphology, a model following Utracki was applied taking into account the viscosity ratio and the respective volume contents of each phase. Detailed transmission electron microscopic investigations of the blend morphologies demonstrated excellent agreement with theory. Moreover, quantitative evaluation of the observed microstructures allowed further description of the degree of blend co-continuity. Thus, desirable compositions of the ternary blend systems could be identified which potentially show enhanced properties such as a high heat deflection temperature, an elevated strength, stiffness, and ease of processing. Finally, a optimum (PPE/PS)/SAN blend system that has been optimised regarding the aforementioned properties was compatibilized by polystyrene-b-poly(1,4-butadiene)-b-poly(methyl methacrylate) triblock terpolymers. Due to the interfacial enrichment of the block copolymer, nanostructured blend morphologies were observed. In the view of these results, pathways to control both the micro- and the nanostructure of PPE/SAN blends are derived, potentially useful to enhance the mechanical as well as thermomechanical property profile.

I nfluence of temperature on morphology, structure and crystallinity of Poly (vinylidene fluoride) (PVDF) nanofibers was investigated in this study. The Wehilmy technique and viscosity testing apparatus were used to evaluate the surface tension and viscosity of electrospun solutions at various ambient temperatures. Surface morphologies and diameters of nanofibers were examined by Field-emission Scanning Electron Microscopy (FE-SEM) and atomic force microscopy (AFM). It was found that the surface morphologies were obviously affected by ambient temperature. This dependence was attributed to the change of the properties of Poly (vinylidence fluoride) solutions with temperature. The thermal properties and crystal structures of the PVDF nanofibers electrospun at different temperatures were also studied by differential scanning calorimetry (DSC), and Xray diffraction (XRD). The results revealed that the crystallinity and thermal properties were improved by increasing the ambient temperature during electrospinning

In the present work, the effect of different acid treatment times of singlewalled carbon nanotubes (SWNTs) on the mechanical and thermal properties of polypropylene (PP)/maleated polypropylene (PP-g-MA) nanocomposites was investigated. The acid treatment process was based on a mixture of concentrated sulphuric and nitric acids. The SWNTs were treated with the acid mixture for 1, 3, and 6 h. FTIR, Raman spectroscopy and TEM revealed the values of carboxylic groups, graphitization and morphology of acid treated SWNTs, respectively. The thermal and mechanical properties and the morphology of nanocomposites were investigated by tensile tests, DMTA, DSC, and SEM.

The aim of this work was to analyze the hydrophilic and surface properties of semi-IPN hydrogels with good electroactive properties based on poly (acrylamide) (PAAm) and conductive polymer poly(3,4-ethylene dioxythiophene)/ poly(styrenesulfonate) (PEDOT/PSS). The hydrogels properties were analyzed by degree of swelling (DS), drop water contact angle (DWCA) and atomic force microscopy (AFM). In addition, the state of water in the hydrogels was estimated by differential scanning calorimetry (DSC) analysis. Results revealed that the presence of PEDOT/PSS reduce the hydrophilicity of the network, mainly those prepared with lower cross-linking density, demonstrating that PEDOT/PSS chains (or their segments) are displayed in surface hydrogels. The possibility of producing PAAm-PEDOT/PSS hydrogels with controlled properties in a desired range of values is of key importance to optimize its use in several applications, mainly in optical devices, capacitors, artificial muscles, and rechargeable lithium batteries

Poly(butylene terephthalate) (cPBT) synthesized from cyclic Butylene Terephthalate oligomers (CBT) was used as a matrix for carbon fibre (CF) conducting polymer composites (CPC). DSC, rheological studies and measurements of torque of CBT/CF were performed in order to optimise the processing conditions of CPC. DC and AC measurements were carried out for these composites and have shown a low percolation threshold for cPBT/CF.

Photo-oxidative degradation of LLDPE films (~ 250 μm thick) containing varying amounts of galbanic acid (a type of coumarin derivatives) was investigated by exposing the films to an artificial sunlight (emitted by 300 W OSRAM Ultra- Vitalux lamps) at 40°C for extended time periods. Photo-oxidative degradation of the neat polymer film and the LLDPE films containing benzophenone (an active photo-initiator for PE) and coumarin alone were also studied under similar conditions for comparison. The rate of photo-oxidation was assessed by measuring tensile properties, gel content, carbonyl index, molecular weight and density. It was shown that galbanic acid was highly effective in accelerating photo-oxidation of LLDPE films and an outstanding acceleration of photo-oxidation was observed for the film containing 0.2 wt % of galbanic acid in comparison with the film containing the same amount of benzophenone. However, the film containing coumarin did not exhibit considerable difference in behaviour in photo-oxidation relative to the neat LLDPE film during the exposure time. On the basis of the obtained results, the prooxidant activity of galbanic acid was described in terms of activity of the functional groups existing in the substituted moiety of its molecules.

In order to obtain linear and high molecular weight Ru(II) coordination polymers, we investigated the reaction conditions for the direct one-step metallopolymerization of bis -terpyridine poly(ethylene glycol) 3 with RuCl 3 in the presence of reducing agents. Here we discuss the direct synthesis method, the optimization and the purification of the water soluble Ru(II) chain extended poly(ethylene glycol). The optimization of the metallo-polymerization was monitored by SEC. For the highest molecular weight Ru(II) coordination polymer 4 obtained in this study, full characterization was performed by 1 H-NMR and UV-Vis spectroscopy as well as SEC proof for the formation and the stability of the designed structure

A novel hydrogel has been synthesized by grafting methacrylic acid (MAA) onto Gum arabic (GA) through free radical graft co-polymerization in the presence of potassium persulphate (KPS) as an initiator and hexamethylene tetramine (HMTA) as a cross-linker. Various reaction parameters like reaction temperature, reaction time, concentration of initiator, amount of solvent, pH, concentration of monomer and concentration of cross-linker were optimized. GAcl- poly(MAA) was characterized by FTIR spectroscopy, SEM and TGA-DTA techniques. Optimized polymer was studied for its salt-resistant swelling behavior in different solutions: NaCl, MgCl 2 , CaCl 2 , FeCl 3 , ZnCl 2 and BaCl 2 as a function of salt concentration, temperature and pH. It was observed that GA-cl-poly(MAA) exhibits following salt-resistant swelling trend in different salts: NaCl > ZnCl 2 > MgCl 2 > CaCl 2 > BaCl 2 > FeCl 3

New biodegradable polymeric hydrogels based on biocompatible materials, glucose acrylate (GA) and methacrylic acid (MAA) were designed and synthesized. In the first time, the glucose-6-acrylate-1,2,3,4-tetraacetate (GATA) monomer was prepared under mild conditions. The removal of protecting acetate groups from GATA will be carried out before the polymerization and then, the corresponding water soluble glycomonomer (GA) was obtained. This deprotected glycomonomer can be polymerized in aqueous media, which points to a way to obtain polymers with applications in biomedical and biochemical fields. Hydrogel synthesis was carried out by free-radical polymerization of the co-monomers using persulfate as an initiator and N,N′-methylenebisacrylamide as crosslinker. The hydrogels was characterized by FT-IR. Equilibrium swelling studies were carried out in enzyme-free simulated gastric and intestinal fluids (SGF and SIF, respectively). The swelling behaviour of the copolymers was dependent on the content of MAA groups and caused a decrease in gel swelling in pH 1 or an increase in gel swelling in pH 7.4. Model drug, 5-aminosalicylic acid (5-ASA) was entrapped into these hydrogels and the in vitro release profile of this drug was established separately in both enzyme-free SGF and SIF. Based on the great difference in swelling ratio at pH 1 and 7.4 for these hydrogels, it appears to be good candidates for colon-specific drug delivery.

In this article, the possibility of obtaining the recycled material based on waste polypropylene (WPP) and waste ground rubber tire powder (WGRT) has been studied. It has been proved that partially replacing WPP with PP-g-MA increased the elongation at break of WPP/WGRT blends, whereas decreased the thermal stability. The presence of compatibilizer increased the elongation at break and thermal stability of WPP/WGRT blends, whereas decreased the processing flowability, as revealed by using universal testing machine (UTM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and capillary rheometer. Moreover, the tendency of the change became more obvious with the content of PP-g-MA and compatibilizer or with the combination of PP-g-MA and compatibilizer. In addition, the improvement of the nonpolar compatibilizer (SEBS) in properties of WPP/WGRT blends was better than that of the polar compatibilizer (SEBS-g-MA).

A novel initiator, 2-benzothiazol-2-yl-5-bromomethyl-phenol (BYBP) containing excited state intramolecular proton transfer (ESIPT) fluorophore was synthesized. Atom transfer radical polymerization (ATRP) of styrene was conducted successfully using BYBP as initiator, cuprous bromide (CuBr)/N,N,N’,N”,N’-pentamethyldiethylenetriamine (PMDETA) as catalyst, and cyclohexanone/DMF (m cyclohexanone : m DMF = 1: 1) as solvent. Factors such as the reaction temperature and molar ratio of catalyst to initiator, which could affect the ATRP system, were discussed in the paper. Chain extension was conducted using polymer as the macro-initiator which was characterized via 1 H NMR. The optical property of initiator was well preserved in the obtained polystyrene, and the endfunctionalized polystyrene exhibited obvious fluorescent emission at about 530 nm.

Carbon nanofibers (CNFs) were modified via plasma polymerization using methyl methacrylate (MMA) as monomer and used as reinforcements for polymethyl methacrylate (PMMA). Conditions of the MMA plasma process in a specially designed reactor and plasma-polymerized methyl methacrylate (PPMMA) films were studied. The study involved varying the process time at a constant plasma power of 100 W and a constant MMA flow rate (0.15 cm 3 per min). Nanocomposites of PPMMA-coated CNFs and PMMA were prepared with 0.5, 1.0, 2.0, 4.0 and 8.0 %wt of treated CNFs. The effect of the MMA plasma on the CNFs was analyzed. Dispersion of the modified CNFs was evaluated in several solvents. The results confirmed a change in hydrophobicity of the treated CNFs. The inclusion of treated CNFs exhibited substantial impact on the properties of the PMMA/CNF nanocomposites. The thermal and mechanical properties of the PMMA/CNF composites were examined. It was found that the thermal stability increased by about 8% and the Young´s modulus significantly enhanced by as much as 178% when compared to PMMA with no CNFs.

Hydrogels comprising of zwitterionic repeat units were synthesized. The amine groups of the poly (ester amine) were quaternized with 1,3-propane sultone. The gelation was observed on treatment with sultone. The hydrophilic gel thus formed is sensitive to temperature, pH, ionic strength and nature of electrolytes in aqueous solution. In absence of any electrolyte, the extent of swelling decreased with temperature, but in the monovalent salt solution the equilibrium swelling diminished with temperature and the contrary behaviour was experiential in bivalent electrolytes.

Poly(ethylene terphthalate) (PET)/organomontmorilonite (OMMT)/maleic anhydride ethylene-propylene-diene rubber (EPDM-g-MA) nanocomposites were prepared via melt blending of the ingredients in a Haake Rheocord mixer. To make the hybrid composites, four different blending routes were examined: 1) preparing EPDM/EPDM-g-MA (EPMA)/organoclay nanocomposite and then blending it with PET, (S1), 2) dispersion of organoclay in PET and then blending it with EPMA, (S2), 3) blending PET with EPMA and then mixing it with organoclay, (S3), 4) blending PET, EPMA and organoclay in a single process, (S4). The microstructure of the PET/(EPMA)/organoclay ternary hybrids were characterized by X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The result showed that the blending sequence greatly affects the dispersion of organoclay in the polymer matrix as well as the microstructure of the blends. Mechanical behavior of the blends including tensile and impact properties were also studied. Results revealed that PET/ (EPMA)/organoclay nanocomposites made by mixing sequence, S1, has the maximum tensile and impact strength among the others. This was attributed to its fine “Sea-Island” morphology and good dispersion of the organoclay in the continuous PET matrix.

New polyimides with 1,2,3-triazole units were prepared by click reaction of α,α’-bis(azidosuccinimide)s with bispropargyl monomers or AB-monomers containing azide and propargyl groups. The α,α’-bis(azidosuccinimide)s were obtained by the addition of hydrazoic acid to bismaleimide monomers. The structure of monomers and polymers was confirmed by FTIR and 1 H-NMR spectroscopy and all synthesized compounds were characterized through thermal methods.

The reaction between urea and ethylene carbonate occur with partial release of CO 2 and partial incorporation of carbonate groups into products. The carbonate groups were found to be attached both to nitrogen of urea and to oxyethylene chain. The most effective catalyst of the synthesis was potassium carbonate. The hydroxyethyl and hydroxyethoxy groups of urea derivatives undergo partial dimerization to form carbamate groups in the products. The products of reaction between urea and ethylene carbonate have good thermal stability, they start to decompose at 200°C. The obtained products can be used as polyol components for polyurethane foams. Polyurethane foams obtained from hydroxyethoxy derivatives of urea (EC8) are rigid products of low water uptake, good stability of dimensions, low mass loss on 30 days heating at 150°C, enhanced thermal stability and good compressive strength.

Under the degradative action of γ-rays, low density polyethylene (LDPE) blended with 5% polypyrrole (PPy) was oxidized extra slow than the neat polymer. FTIR and UV-Viz spectroscopy’s were used for the assessment of the accumulation of oxygen-containing products. The transmittance recorded for LDPE at characteristic bands was higher than similar features obtained for LDPE/PPy samples. The protective action of PPy against oxidative ageing of polymer substrate is due to the movable proton belonging to pyrrole ring. A protection mechanism scheme is proposed for antioxidant activity of polypyrrole

Naturally occurring halloysite nanotubes (HNTs) with hollow nanotubular structures were used as a new type filler for polyhydroxyurethane. The polyhydroxyurethane/halloysite nanocomposites (PHU/HNTs) were prepared by the in-situ surface-initiated polymerization of a five-membered cyclic carbonate 2,2- bis[p-(1,3-dioxolan-2-one-4-yl-methoxy) phenyl] propane (B5CC) and hexa methylene diamine, from the surfaces of the aminopropyl halloysite nanotubes (APHNTs) for the first time. The percentage of grafting (PG %) and the grafting efficiency (GE %) of 41% and 23% were calculated from the results of the thermogravimetric analysis (TGA) and from the results of elemental analysis (EA) respectively after the free polyhydroxyurethane was washed off. The chemical grafting of the polymer was also confirmed using FTIR; the morphology of the silica nanotubes in the nanocomposite was examined by transmission electron microscope (TEM).

A series of anionic polyurethane prepolymers with different molecular structures were synthesized. Different amounts of hexamethylene diisocyanate (HDI) and toluence diisocyanate (TDI) were employed in the synthesis. When the carboxylic content was 0.3 mmol/g, the colloidal stability of the polyurethane dispersions was rather good and their particle size was nano-scale. Moreover, no acetone or other solvent were used during the process of emulsification. The structures of the polyurethane prepolymers were characterized by Fourier transform Infrared spectrometry with attenuated total reflectance (FTIR-ATR) and Gel permeation chromatography (GPC). It was found that the mass ratio of HDI to TDI was able to be quantitatively analyzed by means of FTIR-ATR. The molecular weight and distribution did not show a regular trend with the changing of HDI/TDI ratio. The influence of diisocyanate on the particle size and the coating properties was investigated. It seems that hexamethylene diisocyanate was helpful for obtaining nano-scale particles. These polyurethane dispersions could obtain an average particle size less than 100 nm when mass ratio of HDI/TDI was above 0.25. The polyurethane dispersions with nano-scale particle had a transparent appearance with a bluish cast. It is indicated that the hydrophilic efficiency would be improved and the coating hardness decreased if more HDI was employed.

An experimental study of residual thermal stresses has been carried out in injection molded virgin and recycled high density polyethylene (HDPE) blends. Effects of blend concentrations on residual stresses were investigated under different injection conditions such as melt temperature, mold temperature and cooling time. Layer removal technique was used for measuring residual stresses. In order to determine the relation between the residual stresses and material characteristic of HDPE blends, mechanical and morphological properties of the blends were also investigated. Elastic modulus and impact strength were important key factors for determining the blend characteristics. As a result, it was found that HDPE blends gave higher residual stresses but lower impact strength with higher elastic modulus when recycled concentration was increased. Furthermore, it was seen that shape and size of the crystallites were also effective on residual stresses. Small and spherulitic crystallite structured blends such as 30 % recycled HDPE induced reduction in residual stresses due to easier relaxation with lower elastic modulus and higher impact strength while lamellar crystallite structured blends such as 50 % recycled HDPE gave higher elastic modulus but lower impact strength with higher residual stresses.

Owing to their unique structure and property, natural cyclodextrins and their chemically modified derivatives can include many kinds of organic monomers to form guest/host complexes. The formation of these complexes results in significant changes of the solubility and activity of the guest molecules, but without chemical modification. It is found that the complexed hydrophobic monomers can be successfully polymerized directly in water without any organic solvent or surfactant, which induces a green way to polymer synthesis. It is found that this new cyclodextrin-mediated polymerization method differs strongly from classical methods. The present article reviewed the formation and the structure of the cyclodextrin/monomer inclusion complexes, and the influence of cyclodextrins on polymer synthesis. At last, the possible theory of the cyclodextrin-mediated reaction is discussed.

Ionic liquid [bmim]PF6 (1-butyl-3-methylimidazolium hexafluoro phosphate) was synthesized and characterized. It was used as the plasticizer for poly(L-lactide) (PLLA). The glass transition temperature ( T g ) and the thermal stability of the plasticized PLLA samples were measured by thermogravimetry (T G ) and differential scanning calorimetry (DSC). Compared with poly(ethylene glycol) having M w of 300 g/mol (PEG 300 ), TG results showed that the thermal stability of PLLA plasticized with ionic liquid was better than that of PLLA plasticized with PEG 300 . The T g of plasticized PLLA decrease with increasing the content of ionic liquid [bmim]PF 6 from 2 wt.% to 10 wt.%. The T g of PLLA can be reduced to 40°C when the content of ionic liquid [bmim]PF 6 was 10 wt.%. The materials of PLLA with plasticizer were also investigated using polarizing microscope (POM), the results of which indicate that the movements of PLLA chains were improved when ionic liquid plasticizer was used.