Band 9, Heft 1

This paper is directed towards PVA monofilament with good mechanical properties and super denier, which was produced with the gel spinning technique, first used by K. YAMAURA, used to strengthen the concrete. The structure and properties of PVA fiber were affected especially by extraction conditions, including the temperature, the solvent content and the duration of the extraction, all of which were studied and the optimum parameters were selected.

Methacrylate-terminated Poly(1,3 dioxolane) (PDXL) macromonomers were synthesized by cationic ring-opening polymerization in the presence of 2- hydroxypropyl methacrylate (2-HPMA) as transfer agent. Molecular weights, polydispersity index and functionality of the PDXL macromonomers were evaluated by size exclusion chromatography (SEC) and 1 H nuclear magnetic resonance spectroscopy ( 1 H-NMR). Copolymerizations of PDXL macromonomers, of different molecular weights, with styrene (St) and methyl methacrylate (MMA) were carried out using various feed molar ratios. The resulting polymers confirmed the grafting of PDXL with PS and PMMA by SEC and 1 H-NMR Monomer reactivity ratios between the macromonomers and the comonomers were estimated from the copolymerization results. Macromonomer reactivity depends on the comonomer considered. Glass transition temperatures of the copolymers were found to decrease with an increase in the amount of PDXL in the copolymers. The values of T g depend on the composition and the size of the PDXL grafts.

The reaction of hemicelluloses, isolated from wheat straw, with acrylamide in alkaline aqueous solution was investigated. The degree of substitution (DS, up to 0.65) of the products could be obtained by adjusting the molar ratios of reagent to xylose unit in hemicelluloses (1.0-10.0) and the molar ratios of catalyst to xylose unit in hemicelluloses (0.5-1.6). Changes in the structure of hemicelluloses were verified by FT-IR and 1 H and 13 C NMR spectroscopies. The results showed that carbamoylethyl groups surely were grafted onto the main chain of hemicelluloses. Moreover, it was also found that the saponification of carbamoylethyl groups to carboxyl groups occurred in alkaline medium. The behavior of modified hemicelluloses was monitored by means of thermo gravimetry (TG) and differential thermal analysis (TGA). It was found that the products had a lower thermal stability than the native hemicelluloses.

In this study three series of polyetherurethanes (PEU) based on Terathane ® (polytetramethyleneetherglycol - PTMEG, M n 1400) as polyol; isophorone diisocyanate (IPDI), 4,4’-methylene-bis-(cyclohexyl-isocyanate) (HMDI) and hexamethylene diisocyanate (HDI) as aliphatic diisocyanate components; 1,4- butanediol (BD) and glycerin (Gly) as chain extenders were synthesized. The glycerin as triol is responsible for the crosslinking structures. All polyether urethanes were synthesized by prepolymer method. The PTMEG was reacted with diisocyanate to realize a diisocyanate-terminated prepolymer, which in next step was extended with blend of the 1,4-butanediol (BD) and glycerin (Gly) in different proportion. The influence of the diisocyanate structure and chain extender functionality on the thermal, mechanical and wettability properties were the aim of this study. The physical, mechanical and wettability properties of these polymers were measured according to standard methods. All polymers were characterized by conventional characterization methods. Different methods of thermal analysis (TGA and DSC) were used for characterization. Wettability was estimated by determination of the dynamic contact angle. The structures were confirmed by FTIR and H-NMR analysis. The results show that the thermal stability, mechanical and wettability properties of the final products are influenced by the diisocyanate and chain extenders nature.

The influence of polymerization temperature (from -25 to +25 oC) on molecular weight, crystallinity, electrical conductivity, thermal and morphological properties of polyaniline has been investigated. Aniline was oxidized in an aqueous medium with ammonium persulfate and 1.0 M hydrochloric acid. The reaction mixture freezes below -10 oC and hence lithium chloride was used in sufficient amount to prevent freezing. As the reaction temperature decreases, both the molecular weight of polyaniline and its crystallinity increase. Thermal studies show a common three step decomposition pattern irrespective of the temperature used during synthesis. The morphology of polyaniline changes from granular (reaction in liquid medium) to tubular (polymerization in the frozen state). Thermal analysis indicated that the polyaniline stability increased with decreasing synthesis temperatures. Electrical conductivity of polyaniline was found to be independent of the polymerization temperature and, consequently, of the molecular weight.

Guar gum-g-polyacrylamide is a graft copolymer which is used for many industrial applications. This paper outlines the details of synthesis of guar gum -gacrylamide by using potassium peroxymonosulphate/ mercaptosuccinic acid redox pair in an inert atmosphere and their characterization by infrared spectroscopy, UV analysis and study of swelling and thermal properties. Grafting characteristics: %G, %E, %C, %A and %H were determined by using Fanta’s definition; rate of grafting was also calculated. On studying the effect of reaction conditions on grafting characteristics, it was found that the optimum concentration of peroxymonosulphate, mercaptosuccinic acid, hydrogen ion, acrylamide and guar gum for maximum % of grafting were 8.0×10 -3 , 3.2×10 -3 , 8.0×10 -3 , 16.0×10 -2 mol dm -3 and 60.0×10 -2 g dm -3 respectively. The optimum time duration and temperature of reaction were found to be 120 min and 40 °C respectively. During the study [H + ] variation showed prompt changes on grafting characteristics. It was found that after 310 °C the polyacrylamide grafted guar gum was thermally more stable than pure guar gum.

Poly(ethylene oxide)- b -poly(2-hydroxyethyl methacrylate) (PEO- b - PHEMA) was synthesized by successive atom transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate（HEMA） monomer using PEO-Br macroinitiator as initiator, CuBr/CuBr2 and 2,2‟-bipyridyl (bpy) as catalyst and ligand. IR, 1H NMR, and GPC analysis indicate that PEO- b -PHEMA block copolymer with low polydispersity index ( M w /M n ≈ 1.1) has been formed. Selfassembly of this double hydrophilic block copolymer in the selective solvent and water was also studied. Owing to the high hydrophilic nature of the PEO and PHEMA blocks, this double hydrophilic block copolymer cannot disperse well in water. So block copolymer was modified by part esterification of PEO- b -PHEMA with acetic anhydride, which increased the hydrophobic group of the PHEMA block. The TEM results show that this block copolymer spontaneously form well-defined micelles in water.

Quality of injection molded parts of semi-crystalline polymers has been the subject of intense interest from both analytical and industrial points of view. Crystallinity profile plays an important role in determining mechanical properties of a part and its quality. Therefore it is important to analyze the effect of injection molding parameters on the crystallinity profile of the molded parts. In this study, finite element analysis has been used to solve the equations of mass, momentum, and energy conservation simultaneously with the equation of crystallization kinetics to predict melt front, its solidification and crystallinity profile. The results from our numerical analysis have been compared with the reported experimental results. Furthermore, progress of the crystallization is proposed to be a proper criterion for estimation of the eject time. Finally, the effects of mold and melt temperature on the eject time; part temperature and average degree of crystallinity, for a specific compound are also presented.

Low sample recovery may be one limiting parameter in Liquid Chromatography at the Critical Adsorption Point (LC-CAP) of high molecular weight polymers. We aimed at playing on different experimental parameters in LCCAP of high molecular weight polystyrenes (PS) in order to reach maximum sample recovery. The nature of adsorli and desorli, the temperature, the nature of the column surface and the pore size were studied as regard to their influence on sample recovery. Evaporative Light Scattering was used for detection. We demonstrated that almost all experimental parameters are correlated and that in any case, the lower the adsorli content, the better the sample recovery. Molecular weight limit for good sample recovery could be pushed from as low as 100 000 for the THF/cyclohexane mixture and silica columns to above 1 000 000 for the DCM/n-hexane mixture and amino-silica columns.

In the present work, the double emulsion (W/O/W) method was used to microencapsulate a protein model (Bovine Serum Albumin) in a biodegradable polymer poly(lactide-co-glycolide) (50:50) (PLGA). Colloidal and physicochemical characterization of PLGA based microspheres was investigated after their “crude” preparation and after drying and redispersion processes. Particle morphology and size were studied by scanning electron microscopy and by laser diffraction analysis. Electrokinetic study and colloidal stability were also studied as a function of pH and salinity of the medium. Atomic force microscopy (AFM) was used to study the surface properties. It was found that smooth microspheres were obtained after the drying process. The Atomic force microscopy results of microspheres stored for one month in water show softness and surface irregularity caused by the microspheres degradation. The colloidal stability of theses microspheres is mainly governed by repulsive electrostatic interaction due to the PLGA charge. The used amount of stabilizing agent poly(vinyl alcohol) (PVA) is low enough to ensure the sterical stabilization. Drying process has no effect on the surface properties and colloidal stability of the prepared microspheres.

N,N´ -(3,3´,4,4´-Benzophenonetetracarboxylic)-3,3´,4,4´-diimido-di-Lamino acids (1a-1d) and N,N´ -pyromelliticdiimido-di-L-amino acids ( 2a-2d ) are prepared from the reaction of 3,3´,4,4´-benzenetetracarboxylic-3,3´,4,4´- dianhydride or pyromellitic dianhydride with the corresponding L-amino acids in a solution of glacial acetic acid/pyridine (3:2) at refluxing temperature. 4-(4-((4- Hydroxyphenylimino)methyl)benzylidene amino) phenol ( 3 ) is prepared from 4- amino phenol and terephthaldialdehyde in refluxing ethanol. Interfacial polycondensation method was used to prepare the corresponding polymers ( PEII1- 8 ) in two immiscible solvents (water/dichloromethane). The resulting poly(esterimide- imine)s ( PEIIs ) having good inherent viscosities (0.13-1.25 dl g-1), optical activity and thermal stabilities is obtained in high yields.

Poly( p -dioxanone) (PPDO) and poly(ethylene succinate) (PES) prepolymers were reacted together using toluene-2,4-diisocyanate (TDI) as a chain extender to produce high molecular weight of chain-extended products of PPDO and PES (PPDOES) in a suitable reaction condition. The novel biodegradable polymers were characterized by 1 H-NMR, DSC, POM and WAXD. DSC measurement shows that PPDOES has only one T g , which means that PPDO has good compatibility with PES. Beside this, the glass transition temperatures and the melting temperatures of PPDOES increased with the increase of PES content. The crystallization rate of PPDOES was slower than that of PPDO as confirmed by DSC and POM. The diffraction peaks of PPDOES appear at the same 2θ angles as that of homopolymers, suggesting that PPDO and PES segment of the chainextended products reserve their own crystallization form. The results of thermal oxidative degradation show that chain-extended products have better thermal stability than PPDO.

Hydrosilylation of bulky carbosilanes [CH 2 =CHRC(SiMe 2 R') 3 , R=CH 2 , (CH 2 ) 3 or SiMe 2 ; R'=Me or Ph] with oligosiloxane precursors [M(D 2 D H ) 7 D 2 M, M(D 2 D H 2) 11 D 2 M, PDMS x% -PMHS 100-x% (x=85, 50, 30, 0)] was carried out. The relationship between the mobility of siloxane chain and the type of carbosilane moiety, as well as the type of distribution of carbosilane group along the polymer chain, was consecutively studied. Carbosilane substituents, due to their exceptional steric requirements, have been shown to strongly affect thermal properties of siloxane oligomers, implying a substantial change of the chain flexibility and free volume of modified oligomers.

A series of acrylonitrile(AN)-methyl acrylate (MA) copolymers (AN/MA) with molar ratios of 100/0-70/30 were synthesized by water depositing polymerization. One to three percent of boric acid (BA) was adopted as a stabilizer to enhance the thermal stability of AN/MA. The copolymers and the mixtures of copolymers treated with BA were characterized by using Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (1H NMR), Gel Permeation Chromatography (GPC), Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), X-ray diffraction (XRD) and Optic Microscope. The results show that melting point ( T m ), glass transition temperature ( T g ) and crystallinity of the copolymer decreased while decomposition temperature ( T d ) increased with the increase of MA content. T m of AN/MA dropped to 174 °C and T d rose up to 321 °C when 15 mol% MA was incorporated. It was worthy to note that Tm of the copolymers increased conspicuously after being treated with BA. Stability of AN/MA with a molar ratio of 85/15 containing 1 wt% BA improved remarkably. The mixture can be kept stable up to 30 min at 220 °C.

A retardation effect of boric acid on the cyclization reaction of polyacrylonitrile (PAN) was clearly observed by Fourier transform infrared spectroscopy. The Lewis acid nature of boric acid probably accounts for this retardation effect. A quantitative evaluation of this effect was also made, indicating two potential applications, i.e., high temperature stabilization and melt spinning, which are favourable for the cheap and fast fabrication of PAN-based carbon fibers.

A new photoactive polymer poly(amide-imide), was fabricated by reacting two synthesized monomers, N,N'-(4,4'-oxy-bis(4,1-phenylene))-bis-(1,3- dioxo-1,3-dihydroisobenzofuran-5-carbox amide) and N-(4,6-diamino-1,3,5- triazine-2-yl)-1-naphthamide. Polycondensation reaction of the two monomers was performed under 10 min microwave irradiation in o-cresol as solvent for producing a photoactive poly(amide-imide) in a quantitative yield. The resulting polymer was characterized by FT-IR, 1 H-NMR, TGA techniques and its solvatochromic and fluorescence properties were investigated in different solvents. The poly(amideimide) exhibit broad fluorescent band, and the fluorescence intensity is related to the intermolecular chain-chain or chain-solvent interaction. Also the self-quenching mechanism was studied according to the specific behavior of the polymer in different solvents and the self-quenching rate constant for the association reaction in the excited state (Kq) could be measured from the Stern-Volmer equation. This kind of fused system and diamines show various electron migration mechanisms and photoluminescent properties in the singlet excited states.

Our aim was to investigate the texture of hydrated biopolymer matrices that are now being considered in the design of pharmaceutical controlled-release dosage forms, in order to determine their influence on the release of an active compound. Prolonged release of pentoxifylline, a highly soluble drug, is needed for once-daily administration to achieve its therapeutic effect. For this purpose, pentoxifylline was incorporated in a polymer matrix made of a combination of xanthan and locust bean gum (XLBG), both of which are of biotechnological origin. Different methods were used to investigate the interplay of the XLBG gel structure characteristics in the absence and presence of 200 mM CaCl 2 on pentoxifylline release: drug-release studies, determination of swelling, erosion, and viscoelasticity of the gel, as well as its texture analysis and microscopic imaging. From the results obtained, the following conclusions can be drawn: the pentoxifylline release from XLBG matrices in water was prolonged for 24 h whereas from the control lactose formulation was completed within 30 min. The presence of Ca 2+ ions in water resulted in faster pentoxifylline release, in spite of less swelling and erosion. However, the rheology, texture analysis and scanning electron microscopy revealed that in the presence of the Ca 2+ ions the gel layer of the XLBG was more cohesive and thinner, as the attraction for water molecules was lower due to the condensation of counter-ions on the xanthan carboxylic-moieties, and consequently greater interpolymer interactions. Therefore, relatively larger amounts of free water molecules were available within the XLBG hydrogel in the presence of Ca 2+ , allowing faster drug dissolution and diffusion. Here, the presence of Ca 2+ ions had a completely opposite effect on XLBG gel structure and drug release in comparison with other more investigated matrix polymers like alginate or non-ionic cellulose ethers. A firm matrix structure that is accompanied by low swelling and erosion cannot guarantee a more prolonged drug release.

Well-defined naphthalene end-capped poly(styrene)- block -poly(Nisopropyl- acrylamide)- block -poly(styrene) (PS- b -PNIPAM- b -PS) amphiphilic triblock copolymers with different molecular weights and block copolymer compositions were successfully prepared via consecutive reversible additionfragmentation chain transfer (RAFT) polymerizations using a novel RAFT reagent, S,S'-bis(1-naphthylmethyl) trithiocarbonate (BNTTC). The aggregation behaviour of the prepared PS- b -PNIPAM- b -PS in water/DMF mixture was studied by transmission electron microscopy (TEM). The effect of the copolymer concentration, PNIPAM block length and the irradiation of UV-light on the sizes and morphologies of micelles were also investigated.

Poly(vinylidene fluoride) (PVDF) nanocomposites filled with various expanded graphite (EG) contents were prepared via melt-mixing followed by hotpressing. The structure, electrical, and thermal properties of resulting nanocomposites were investigated. X-ray diffraction results indicated that the EG additions do not lead to structural changes of PVDF. Differential thermal calorimetry measurements revealed that EG act as a nucleating agent for PVDF molecular chains. The crystallization temperature shifted to higher temperature with increasing EG content. DMA results showed that the storage modulus and glass transition temperature can be enhanced by adding EG. The nanocomposites were found to exhibit a small percolation threshold of 6.3 vol% due to the large aspect ratio of graphite nano-sheets. A great enhancement of dielectric constant is also found as EG concentration approaches percolation threshold. Both the electrical conductivity and dielectric constant of PVDF/EG nanocomposites can be well described by the percolation theory.

Copolymeric structures with compositional gradient were produced by “in situ” radical polymerization -in water and with redox initiation- of acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) in the presence of an inhibitor (hydroquinone). The inhibitor has a key role in controlling the mixing of precursor solutions because it produces a retardation of the polymerization. Raman spectral analysis confirmed the changes in the composition along the long axis of the produced cylindrical materials. Compression tests were also performed, exhibiting the gradient and reference material’s unique properties, which were well correlated to the compositional pattern.

Three-armed star-shaped poly(ester amine) was synthesized by Michael addition polymerizations of equal molar ratio of ethylene glycol diacrylate (EGDA) and piperazine (PZ) in the presence of a small amount of multifunctional monomer, 1,3,5-triacryloylhexa-hydro-1,3,5-triazine (TT) in CHCl 3 . When the polymerization proceeded almost completely, the molecular weight of the polymers formed were determined by the feed molar ratio of difunctional monomer to multifunctional monomer, and the molecular weight distribution ( M w / M n ) approached the theoretical value ( M w / M n =1+1/ f ). The mechanism of the polymerization was investigated by 1 H NMR and Gel permeation chromatography (GPC). The monomer concentration and the molar ratio of difunctional monomers/multifunctional monomer played an important role in the polymerization.

Carbon nanotubes were introduced into insulating polystyrene (PS) and poly(methyl methacrylate) (PMMA) by means of a latex-based technique. A systematic study of the effect of the polydispersity index, more particularly the presence of different amounts of low molar mass polymer, on the final composite conductivity was performed. Six latexes with varying molecular weight distributions were prepared by means of conventional free radical emulsion polymerization in the presence of different amounts of chain transfer agent, namely n- dodecyl mercaptan. Composites were prepared with both multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs). Shifts in the percolation threshold from 0.9 to 0.6 wt% for MWCNTs and from 0.7 to 0.4 wt% for SWCNTs were observed for PS matrix material, whereas for PMMA matrix material the percolation thresholds shifted from 0.6 to 0.3 wt% for MWCNTs and 0.35 to 0.2 wt% for SWCNTs upon increasing the amount of low molecular weight polymer in the polymer matrix.

In this study, double percolated network of carbon nanoparticles and ceramics powder is used to uncouple electrical and thermal conductivity of polymer composite. The influence of ceramic powders on morphological properties of a biphasic conductive polymer composite (CPC) is investigated by means of rheological measurements. The biphasic materials studied are blends of a thermally conductive polymer phase (syndiotactic poly(styrene) (sPS) filled with boron nitride (BN)) with an electrically conductive polymer phase (high-density poly(ethylene) (hdPE) filled with nano-structured carbon black (NCB)) into a cocontinuous structure. The elastic modulus (with viscous modulus) was found to be the most sensitive rheological property to accurately detect the co-continuous morphology in our system. It was found to be at 40% v/v of hdPE-NCB, which can be interpreted as the phase inversion.

Crosslinking of polyethylene would improve and modify its properties. A preferred method of crosslinking is via its silane grafting, initiated by peroxide. In this study, the grafting reactions of different types of low density (LDPE), linear low density (LLDPE) and high density polyethylene (HDPE) were studied and compared in efficiency, all in a fixed amount of silane (vinyltrimethoxysilane) and peroxide (dicumyl peroxide). Processing for silane grafting was carried out in an internal mixer for 15 minutes at 190 oC, and the silane grafting efficiency was determined through the corresponding peaks in their FTIR spectra. The effect of polymer physical form (powder versus granule) and premixing (the polymer with silane-DCP solution) prior to processing was also determined. In case of LDPE and LLDPE, three types of antioxidants (Irganox 1010, Irganox 1076, and KV10) were incorporated into the reaction mixture to assess their probable interference and effectiveness in grafting reaction. Finally, LDPE was melt blended with ethylene vinyl acetate (EVA) and once again with ethylene propylene diene monomer (EPDM) to investigate their effect on silane grafting efficiency. Amongst different grades of polyethylene, LLDPE had a better efficiency in silane grafting with regard to LDPE and HDPE. Furthermore, the lower molecular weight of polyethylene with narrower molecular weight distribution resulted in the more efficient silane grafting. In case of incorporating antioxidant, Irganox 1010 followed by Irganox 1076 had the best performance for LDPE, however, KV10 turned out to be more suitable for LLDPE. Finally, higher silane grafting efficiency was gained through blending polyethylene with EVA and EPDM.

A novel shape memory polymer based on conetworks (CNs) was synthesized. These conetworks consisting of poly(methyl methacrylate) and poly (ethylene glycol) diacrylates showed excellent shape-memory properties with a recovery ratio of nearly 100%. Moreover, different shape memory effects were discovered in different mediums due to their amphiphilic properties. In addition, a large storage modulus ratio above and below the glass transition temperature(E ratio) , which probably means excellent shape memory effect, were obtained due to the designed CN structure whether crystallization existed or not. It is quite different from the traditional methods to achieve large E ratio values. The versatility of shapememory conetworks potentially provides us a new route to prepare shape memory materials.

A simple one-step method for the chloromethylation of polyethersulfone (PES) under mild conditions provided surface benzyl chloride groups as the active initiators for the surface-initiated atom-transfer radical polymerization (ATRP) to tailor the functionality of the PES membrane. Functional hydrophilic polymer brushes of poly(ethylene glycol)monomethacrylate (PEGMA) and sodium 4- styrenesulfonate (NaStS), as well as their block copolymer brushes, were prepared via surface initiated ATRP from the chloromethylated PES surfaces. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used to characterize the surface-modified membranes. The PEGMA-grafted PES membranes showed great protein resistance to protein adsorption compared to the pristine PES surface.

Studies of kinetics of polymer crystallization are generally performed by heating the material above the melting point, in order to erase previous thermal and mechanical history, followed by rapid cooling to the desired crystallization temperature or by cooling at a constant rate. For poly(3-hydroxybutyrate) this procedure implies some degradation of the polymer chain, which starts below the onset of melting. In this article the effects of melting conditions on the subsequent crystallization kinetics are discussed. It is shown that in order to sufficiently cancel memories of previous crystalline order of the analyzed PHB, it is necessary to bring the material at a temperature higher than 192 °C. Thermal treatments conducted at lower temperatures are not sufficient to destroy all solid aggregates, and crystallization of PHB has an anticipated onset of crystallization due to nucleation occurring via self-seeding. The chain degradation attained upon exposure at high temperatures has much lesser influence on crystallization kinetics than incomplete melting, with some effects detectable on the spherulitic morphology and on the final degree of crystallinity.

Preparation of inorganic-organic hybrids made of polyhedral oligomeric silsesquioxanes (POSS) and polyamide 6 (PA6) has been attempted either by melt mixing of the two components or by in-situ polymerization of -caprolactam (CL) in presence of POSS. The samples have been characterized by wide angle X-ray diffraction (WAXD) and scanning electron microscopy (SEM) techniques. Specific processing conditions (namely, high T in presence of different shear stresses) have been tested. Two different approaches for melt mixing have been used and the morphology of the corresponding systems compared. The melt-mixed pairs prepared in the microcompounder revealed a coarse phase separation, while those made in a simple mixer did not show any perceivable POSS segregation phenomenon, as evidenced by both WAXD data and SEM investigation. Similarly, the in-situ polymerization of CL in presence of POSS did not result in any POSS self-aggregation in the polyamide matrix, achieving a very fine Si dispersion of nanometric dimensions.

Self-assembly of poly(methyl methacrylates) end-capped with -Ge(C 6 F 5 ) 3 groups (PMMA-F) has been studied in a selective solvent (acetone) by means of photon correlation spectroscopy and static light scattering. PMMA-F’s of different molecular weights (MW), were obtained by radical polymerization in the presence of a chain transfer agent, HGe(C 6 F 5 ) 3 . At MW>130 000 conformational and hydrodynamic properties of PMMA-F’s is shown to be the same as of PMMA. At MW less than130 000 an aggregation starts: additional fraction of large scatterers appears in PCS. Large aggregates of R h =200 - 300 nm are likely to be formed by bridged micellar clusters. Presence of large aggregates indicates a super strong segregation limit predicted in the work of Semenov et al.

An optimized and high-performance Monte Carlo simulation is developed to take thorough account of the influence of chain-length-dependent termination rate constant on polymer microstructure in ATRP. According to the simulation results, bimolecular termination rate constant sharply drops throughout the polymerization when chain length dependency is applied to the program. The dependence of on reaction time, as a common feature of ATRP, is almost linear. Moreover, the polymerization proceeds to higher conversion when the chain-length-dependent termination rate constant is applied to the simulation model. In addition, the plot of against reaction time is completely linear; also, the initiator is entirely decomposed at the early stages of the polymerization as the plot of C I against time shows. The concentration of the catalyst in lower oxidation state decreases first and then plateaus at higher conversion. Furthermore, the amount of M t n Y/L used in the polymerization is lower when the chain-length-dependent termination rate constant is employed in the simulation. Finally, the peak of molecular weight distribution of polymer chains shifts toward higher molecular weight during the reaction. Besides, the molecular weight distribution broadens at higher conversion. However, the molecular weight distribution of polymer chains produced under conditions of applying chain-lengthdependent termination rate constant is narrower.

Ag/polyamidoamine nanocomposites were produced by photoreduction of relevant metallic salts in polyamidoamine methanol solutions under room temperature and ambient pressure. The obtained products were characterized by FTIR, XRD, TEM, TGA and DSC techniques. The results showed that Ag nanoparticles were quite uniform in size with a diameter of about 15 nm, and the amount of Ag nanoparticles could well affect the thermal stability and the glass transition temperature of polyamidoamine. As the mass ratio of Ag nanoparticles to polyamidoamine increased, the glass transition temperatures were increased, while the weight loss ratios were decreased. TGA curves indicated that the loading of Ag nanoparticles mainly influences the high temperature thermal stability of polyamidoamine. Moreover, the multistage decomposition profile of DTG curves suggested that the Ag/polyamidoamine nanocomposites of higher silver loading might contain some intermediate Ag+/polyamidoamine type of composites.

Thermoplastic block copolymers based on poly(butadiene) and poly(ε- caprolactone) were synthesised from the ring opening polymerization of ε- caprolactone onto a polybutadiene macroinitiator. The lithium alkoxide macroinitiator results from BuLi addition on hydroxy telechelic polybutadiene (HTPB R45 ® ) chain ends. The reaction is fast (about 5 min) and quantitative, leading to well defined copolymers with PCL/PBHT ratio varying from 45/55 and 18/82. Average molar masses range from 10 000g/mol to 26 000g/mol with PDI about 1.6. 1 H NRM was used to follow the polymerization kinetic and 13 CNMR was used to determine the chemical link between the blocks.

Because of low cost, easily productivity and high thermal conductivity, aluminum (Al) moulds are preferred in the production of the polyurethane (PUR) parts. In this study, adhesion behavior and surface properties of coated materials between mould used in the production of automotive seat and PUR materials were investigated. Four different polymer types were coated on Al mould and they were characterized using contact angle, surface roughness, coating thickness, adhesion, cross-cut and SEM test methods. It was found that, PFA has the least value of surface roughness and ETFE has the highest one in the four different coatings produced. After holding period in isocyanate, decrease were measured on the angle values of all coatings. In the contact angle measurements before and after isocyanate tests, PFA exhibited the highest contact angle value.

Ten poly(amide) oligomers were prepared from four acid dichlorides and two full-aromatic diamines, the latter containing silicon or germanium in their structure. The polymers, which contain Et/Me, Et/Et and nBu/nBu combinations on heteroatom of the acid dichloride moiety, were characterized by spectroscopic techniques, including 29 Si NMR. The yields obtained and the η ιnh values established were low, indicating the low molecular weight nature of the polymers. Thermal stability was also evaluated by TG and DSC techniques. When a methyl group was replaced by a Et, the Tg of the poly(amides) (PAs) was increased in accordance with the gain in the flexibility of the chain. However and in general terms, the PAs with n Bu groups show the inverse effect. Probably, the possibility of an effective interaction between these side chains affects negatively the flexibility of the main chain. On the other hand, PAs that contain single silicon in their structure show lower T g values than the Ge-containing PAs . For the other heteroatom combinations, similar results were obtained. This fact does not agree with the lower size of silicon atom which should increase the molecular rigidity and therefore their T g values. Probably, the influence of the side groups is decisive in hindering the chain rotation. The thermal degradation temperature (TDT) changed in agreement with the packing factor of the chains which was depending on the size of substitute groups. So, when Et group was replaced by n Bu as lateral group, lower TDT were recovered. With respect to the heteroatoms used in the main chain, the TDT values do not show a clear tendency.

The objective of the present study is the introduction of well known and readily accessible analytical methods as FTIR, thermogravimetric (TGA) and evolved gas analysis (EGA) for quantitative determination of the degree of polymerization (DP) and degree of quaternization (DQ)/betainization (DB) of amino-based amphiphilic block copolymers. For this purpose a series of amphiphilic poly(dimethylsiloxane)- b -poly[2-{dimethylamino)ethyl methacrylate] (PDMS- b -DMAEMA) diblock copolymers with DP of the PDMAEMA-block ranging from 22 to 162 was synthesized by atom transfer radical polymerization and analyzed by 1 H NMR, ATR-FTIR and TGA-co-EGA. The determined composition results have shown linear correlation between the FTIR or TGA and the 1 H NMR data and equations allowing the quantitative calculation of PDMAEMA-block DP were found. The errors estimated by ATR-FTIR were less than 1.5%. Further, the PDMAEMA-block was quaternized (or betainized) with DQ (or DB) from 25 % to 100 % and analyzed by TGA-co-EGA. Again, a linear correlation between the quaternized (betainized) PDMAEMA-block mass fraction and the DQ (DB) degrees was obtained by 1 H NMR.

Octaaminophenyl polyhedral oligomeric silsesquioxane (OapPOSS) was prepared as nanofillers and filled to isotactic polypropylene (PP). Maleic anhydridegrafted PP (MAPP) was selected as compatibilizer. The morphology, crystallization, melting behavior and rheologcial behavior of PP/OapPOSS composites with or without MAPP were studied by scanning electron microscopy, differential scanning calorimetry, polarized optical microscope, oscillatory and capillary rheological analysis. The results showed that the morphology, crystallization and rheological behavior of the composites were strongly influenced by the existence of MAPP. MAPP improves the compatibility between PP and OapPOSS because of the reaction of OapPOSS with MAPP. The OapPOSS retards the crystallization of PP while promoting it when MAPP is added. MAPP could decrease the viscosity of PP/OapPOSS probably due to the weaker particleparticle interaction and interface slipping.

Acrylonitrile(AN) was successfully used to copolymerize with itaconic acid (IA) by suspension emulsion polymerization at 70 ˚C under N2 atmosphere for the first time. Porous AN/IA copolymers were prepared by using potassium peroxydisulphate (KPS) as initiator, poly(vinyl alcohol) (PVA) as dispersant and Span60 as emulsifier. Kinetics of suspension emulsion copolymerization of AN with IA were studied. Effects of various mass ratios of water/monomer, initiator concentrations, emulsifier concentrations and dispersant concentrations on AN/IA copolymerization rate and changes of particle size and size distribution with the extension of polymerization time were investigated. It was found that the copolymerization rate increased with water/monomer mass ratio and KPS concentration. Span60 concentration and PVA concentration had no obvious effect on the polymerization rate. Finally, a suspension emulsion polymerization mechanism for AN and IA was proposed.

The diamine monomer, 2,6-bis(p-aminophenyl)-benzo-[1,2-d; 5,4-d’] bisoxazole was successfully synthesized. Three aromatic polyimides (PI) based on 2,6-bis(p-aminophenyl)-benzo-[1,2-d; 5,4-d’] bisoxazole were prepared via a conventional two-stage procedure with a variety of dianhydrides. Their structures and properties were characterized by FTIR, 1 H NMR, TG, DSC and XRD. The intermediate poly(amic-acid)s (PAA) had inherent viscosities of 1.18-1.70 dL/g and could be thermally converted into lightly yellow polyimide films. The resulted polyimides showed excellent thermal stability, and the glass transition temperatures ( T g ) of all polymers were above 280 o C, and the 5% weight loss temperatures of polymers were about 550 o C in N 2 . The solubility of these polyimides in various solvents was evaluated. They were all insoluble in conventional polar aprotic solvents.

A series of polyether chelating resins with pendent biphenyl mesogenic groups were synthesized, and the chemical structure of monomers and polymers were confirmed by IR and 1 H NMR detection. The thermal properties of resins were investigated by the Differential Scanning Calorimetry (DSC) and Polarizing Microscopy (POM), and the results showed that only the product of polyepichlorohydrin grafted with 4-cyano-4’-hydrobiphenyl, i.e., HPCN resin, was a kind of nematic liquid crystal polymer with typical schlieren texture (70-130 0 C) and other resins were semi-crystalline. The results of adsorption experiments showed that all five resins exhibited a higher adsorption capacity (>1.0 mmol/g) for Cu (II) and Hg (II) and medium adsorption ability for Cd (II), Zn (II), Pb (II) and Co (II), however, a poor adsorption capacity (<0.3 mmol/g) for Mg (II), indicating that this type of polyether resins have a better selective adsorption for above metal ions. In addition, the adsorption capacity of HPnCP resins was generally higher than that of HPd and HPCN owing to the existence of terminal pyrrole coordination groups in HPnCP resins.

Ethene-/ɑ-olefin copolymers having a wide range of comonomer contents with comonomers between 4 and 26 carbon atoms in length were characterized by wide angle X-ray scattering (WAXS). It was found that the crystallinities matched fairly well with the crystallinities from DSC and volumetric measurements. An increase of the crystal lattice size was found with increasing comonomer content and comonomer length. Both are attributed to the formation of defects around these short-chain branches in the crystal lattice, which widen it. Increasing the cooling time will lead to a more densely packed crystal structure, if the quenched structure is distorted, i.e. if the sample contains comonomer. A higher molar mass M w widens the average space between chains in the amorphous phase as well as the addition of comonomer. The latter finding is explained by the increasing number of chain ends introduced by the comonomer which increases the free volume in the sample because of the worse amorphous packing of the chain ends.

Ethene-/ɑ-olefin copolymers having a wide range of comonomer contents and comonomers between 4 and 26 carbon atoms in length were characterized by wide angle X-ray scattering (WAXS) and small angle X-ray scattering (SAXS). The data was evaluated with respect to the crystallite size. The half-width of the main crystallite peaks was transformed into the crystallite size s 110 and s 200 using the Scherrer equation. It was found to decrease with increasing comonomer content. The crystal lamella thickness was determined from the long period and the crystallinity of the samples. The crystal lamella thickness was found to decrease with decreasing crystallinity following a 3 rd order polynomial. This means that the introduction of SCBs leads to a decrease of the crystallite size. A higher M w leads to an increase of the lamella size in comparison to lower molecular samples with the same crystallinity. The lamella thickness is limited by the average distance between two short-chain branches which is dependent on the comonomer content.

The cell-material interaction is an important factor to be considered in the applications of biomaterials. The properties of biomaterials, for example crystallinity, would change the cell behaviors such as proliferation, differentiation, morphology and so on. In this article, the research was focused on the relationship between the crystallinity of polymeric substrates and the cell responses. Two kinds of biodegradable poly(L-lactide) (PLLA) films with different crystallinity were prepared and used as substrates for cell behavior study. The PLLA films were fabricated with crystallinity of 19% and 69% through solution casting and isothermal processing, respectively. The crystallinity of PLLA films was characterized by DSC and XRD. The surface morphologies of PLLA films with different crystallinity were observed by SEM. Bone marrow stromal cells (MSCs) isolated from the marrow of new born male Sprague Dawley rats were cultured on the films. The cell morphology, proliferation, total protein amount and alkaline phosphatase (ALP) activities were tested. The results showed that the crystallinity of PLLA films affected the behavior of MSCs greatly.

The nitro group of 4-(p-nitrobenzyl)pyridine was converted to amino group and 4-(p-aminobenzyl)pyridine was prepared by catalytic hydrogenation using hydrazine hydrate/Pd-C systemReaction of 4-(p-aminobenzyl)pyridine with 1,3,5-benzenetricarboxylic acid under appropriate conditions yielded a new diacid containing amide group and pyridine unit. The prepared substances were characterized using FT-IR, H-NMR, and mass spectroscopy and also elemental analysis. Polycondensation reactions of the diacid with different commercially available diols in the presence of benzenesulfonyl chloride afforded new types of poly(amide-ester)s. All the polymers were characterized and their physical and thermal properties were studied. The polymers showed high thermal stability and also enhanced solubility in polar aprotic solvents.

Possibility of determination of the relations among homo- and crosspropagation rate constants on the basis of analysis of the detailed distribution of copolymer chain lengths is presented. Importance of application of correct computation algorithms in Monte Carlo modelling of copolymerization is indicated. A new algorithm for Monte Carlo modelling of polymerization processes is proposed.

The induction of chirality in achiral liquid crystalline azoaromatic polymers with circularly polarized light (CPL) has been studied on well-defined macromolecular derivatives with different molecular structures, synthesized by atom transfer radical polymerization (ATRP). Two methacrylic homopolymers have been investigated: a linear and a three arms star polymer. Both the polymeric samples are featured by low polydispersity and similar average polymerization degree, so that structure-properties correlations are made possible. Irradiation with CPL of one handed rotation sense of casted films and a planar cell of these polymers in the glassy nematic phase allowed to ascertain by UV-Vis and CD spectroscopy the formation of a supramolecular chiral structure with high chirality induced into the material. The results are interpreted in terms of the structural features of the polymers.

Poly(3-azidomethyl-3-methyloxetane) and its copolymers with 3,3- bis(azidomethyl)oxetane were synthesized by cationic polymerization from 3- tosyloxymethyl-3-methyl oxetane and 3,3-bis(bromomethyl)oxetane, using a polyol as initiator and boron trifluoride complex as catalyst, followed by azidation. The final objective is the synthesis of an energetic binder to be used for rocket propellants and therefore the effects of different initiator/catalyst systems on important properties, like, i.e., the molecular weight distribution and the functionality of the polymer, were investigated. It was found that, even though both the operating conditions and the catalytic system were chosen in order to grant the living character of the polymerization, the latter seems to be prevalently driven by an “active chain end” mechanism. In particular, this may lead to the undesired formation of a small quantity of oligomers and to the presence of non-hydroxylic chain-end functionalities. Nevertheless, the average number of OH groups can be strictly controlled when boron trifluoride tetrahydrofuranate is used as catalyst.

The modification of cellulose fibers by grafting specific functions could improve their quality and allow their use for the development of new products. In this work we report about the functionalization of a cellulose fiber network (filters) with organo-polysilazane oligomers by UV-irradiation. Photo-induced grafting, as assessed by contact angle and TGA measurements, was successful: an interesting enhancement of thermal resistance and mechanical properties was obtained. Water repellency was also achieved.

The spectroscopic behavior of thin films of regioregular poly(alkylthiophene)s bearing an optically active alkyl group has been investigated in the solid state under different sample preparation procedures. The experimental results are interpreted in terms of influence of the side-chain substituents on the extent of planarity of the polymeric chains and the formation of optically active chiral aggregates.

Poly(ethylene terephthalate) (PET) has been compounded with lignin (L) by a single-screw extruder. The influence of L presence and its content on the thermal stability of PET has been studied by using thermogravimetric analysis. The experiments carried out in oxidative conditions evidenced the barrier effect of L that interferes to the diffusion of the volatile degradation products to the gas phase and at the same time to the diffusion of the oxygen from the gas phase to the PET matrix. The influence of L on the melting behaviour of PET has been investigated on samples submitted to subsequent annealing steps procedure. X-ray techniques were employed to investigate crystallinity and crystal dimensions of pure PET and PET/L composites. Considering the supermolecular and crystal structure of the annealed samples, their melting behaviour was explained assuming small changes in the melting entropy.

A careful insight into melt compounding procedure is proposed in order to achieve a better understanding and control of the dispersion and orientation mechanisms of organo-clay platelets into LDPE nanocomposites. The method involved is the preparation of a maleic anhydride grafted polyethylene masterbatch containing 10 wt% organo-clay via twin-screw extrusion. A substantial nanodispersion and orientation of clay platelets was obtained as observed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses. Moreover, the nanocomposites prepared by diluting the master-batch through the blend mixing with additional LDPE preserved or improved the exfoliation and lamellae orientation. Finally, the thermo-gravimetric analysis (TGA) showed a significant improvement of the thermal stability while both differential scanning calorimetry (DSC) and XRD evidenced a slight increase of the LDPE crystallinity degree with respect to neat polymer matrices thus suggesting the occurrence of orientation also for the polymer.

Multi-wall carbon nanotubes/poly(butylene terephthalate) nanocomposites have been prepared by in-situ polymerization. Benzimidazolium tetrafluoroborate salts improve the dispersion of carbon nanotubes in the polymer matrix due to the formation of “π-cation” interactions of the imidazolium salt with the surface of the carbon nanotubes. An improved dispersion of the nanotubes in butanediol was also observed using the benzimidazolium salt. The presence of the compatibilization agent gives rise to improved thermo-mechanical properties and electrical conductivity for the nanocomposite. The presence of the nanotubes also consistently increases the thermal stability and enhances the nucleation process on PBT crystallization.

We have recently reported that the volumetric as well as the viscoelastic intricacies of mechanically stimulated glasses can be predicted by coupling the structural relaxation kinetics and viscoelastic response [1, 2, 3]. Here, it will be shown that our approach can be extended to predict the stressstrain behaviour of glassy polymers as function of temperature, strain rate and aging time. In particular, a linear dependence of yield stress on the logarithmic of the strain rate can be obtained, conforming to the classical Eyring-type behaviour. The Poisson’s ratio evolution was obtained from the volume relaxation behaviour highlighting an unexpected correlation between the yield point and the volumetric behaviour.

Vitrification and devitrification of the rigid amorphous fraction (RAF) of poly(ethylene terephthalate) (PET), analyzed during development and disappearance of the three phase structure, are detailed in this contribution. Upon cooling from the melt at a constant rate, the rigid amorphous fraction starts to vitrify when the crystallization process is almost finished, and continues on further cooling. The rigid amorphous fraction is formed in the same temperature range of the secondary crystal growth. Analysis of the low melting endotherm that is observed in isothermally crystallized PET a few degrees above the crystallization temperature reveals a joint contribution of melting and devitrification of the rigid amorphous fraction. The results confirm a link between secondary crystallization and vitrification of the rigid amorphous fraction in semicrystalline polymers. Secondary crystallization takes place in geometrically restricted areas, in which the polymer chains undergo large constraints, so that the mobility of the amorphous chain portions coupled with the crystal phase is reduced. Similarly, the gain in mobility upon partial melting of thinner and/or more defective crystals allows an increase in mobility of the coupled amorphous regions, which results in concurrent mobilization of the rigid amorphous fraction.

In this work the structural variations and mechanical performance of polyethylene/clay nanocomposite drawn fibres, also in the presence of compatibilizer, such as a commercial maleic anhydride grafted polyethylene, PEgMA, was studied. In the isotropic state both systems show intercalated morphology. After spinning and cold drawing, by adding the nanoparticles, the tensile strength as a function of the draw ratio increases and this rise is more pronounced for the filled compatibilized system. The reduction of the elongation at break, on the contrary, is about the same for all the examined samples. The orientation of the macromolecules, evaluated by measurements of the birefringence and calorimetric analysis, is similar for all the samples, but the filled, drawn fibres show a higher level of intercalation and, in particular, some exfoliation, more and more pronounced with the draw ratio and in presence of compatibilizer, as a consequence of the application of the extensional (at low and high temperature) flow. For the three components system with greater affinity between the polymer matrix and clay, the extensional flow is more efficient. The initial intercalated morphology changes to some more intercalation and finally, at the highest anisotropic condition in the presence of the PEgMA, evolves to delaminated clay structure.

The aim of the present study is to correlate the features of the elongational flow-induced morphology to the mechanical properties of polyamide based nanocomposite fibres. Particular attention was paid to modelling the mechanical behaviour of the hybrids which were produced by fibre spinning technique and collected at different draw ratios. Tensile properties of as-spun and stretched fibres were investigated and correlated to their nanostructure through analytical techniques sensitive to different aspects of the hybrids morphology, such as X-Ray diffraction and TEM analysis. In particular, the TEM images of the nanocomposite systems showed intercalated/exfoliated morphology in all hybrids. For this reason, a three-phase Halpin-Tsai model, based on polyamide-6 matrix, exfoliated clay platelets and nanolayer intercalated clusters, was used to fit the experimental data. This method was applied to calculate the Young’s modulus of nanocomposite fibres both as-spun and stretched ones. Moreover, the model was used for predicting the effect of various morphological parameters including the exfoliation degree, clay layer and cluster aspect ratio.

Thermal stability of alkyl and arylalkyl quaternary ammonium cation (onium) in starting chloride salt, in organoclay obtained after exchange with montmorillonite (MMT) and after mixing of the organoclay with isoprene rubber was examined using conventional TGA and by mass spectrometry pyrolysis/GC-MS. Degradation was observed to occur at T ≥ 170 °C for organoclays and the main volatile compounds were identified as tertiary amines, chloroalkanes and alkenes. Mechanisms for their formation are proposed and the role of residual onium chloride and basic centers of layered silicate is discussed.

Nanocomposites were prepared based on diene rubbers and layered clays modified with an alkyl quaternary ammonium cation (organoclay). A diene rubber, either polybutadiene, or synthetic or naturally occurring polyisoprene or styrene-butadiene copolymer, was melt blended with either a preformed organoclay or with a mixture of pristine clay and ammonium cation. Besides isolated lamellae, nanocomposites showed the presence of crystalline organoclays with intercalated organic layers made only by low molecular mass substances, essentially the ammonium cation, and no evidences for the intercalation of polymer chains were observed. Dynamic-mechanical properties of sulphur cured compounds with carbon black as the main filler and a minor amount of organoclay were investigated. The organoclay was found to bring about a reduction of Mooney viscosity, an increase of storage modulus at low temperature as well as an increase of thermoplasticity.

Linear low density polyethylene (LLDPE) films containing different concentrations of perylene (P) chromophores have been prepared by solution-casting and compression-moulding. The light emission features of the films depend on P concentration and polymer films deformation. A well-defined band attributed to the formation of micro/ nano-structured perylene chromophoric aggregates is observed with more than 0.1 wt.% of P in the film. The occurrence of this phenomenon changed the emission colour of the films from a bright blue (noninteracting dyes) to low intense pale yellow (interacting dyes) colour. During film drawing the LLDPE macromolecules reorganization is able to break the P supramolecular organization, leading to the prevalence of the blue emission of monomeric P. The optical behaviour of perylene dyes acting as internal stressstrain luminescent indicators for polyethylene films, provides a powerful tool to detect macromolecular organization.

Novel hybrid organic-inorganic coatings were obtained by photopolymerization and subsequent thermally induced condensation through solgel processes. Both radical (methacrylic) and cationic (epoxy) resins were considered as precursors of the organic phase; tetraethoxysilane (TEOS) was the precursor of the inorganic phase. The effect of the presence of a coupling agent was investigated. Real-time FT-IR analysis was used for evaluating the kinetics of photopolymerization. 29 Si-NMR spectroscopy was used in order to evaluate the degree of condensation of alkoxysilane groups. The results showed the prevalence of Q 3 e T 2 structures indicating an incomplete condensation of the alkoxysilane groups. T 1 and Q 1 signals are not present, thus indicating that for each Si atom, two or more alkoxysilane groups take part to the condensation reaction. FE-SEM analyses evidenced a nanometric organization of the inorganic domains in the polymer matrix. The addition of the coupling agent was found to influence the morphology of the hybrid systems. DMTA and TGA analyses revealed an increase of the Tg values and of the thermal stability by increasing the coupling agent and TEOS content.

Electrospinning technology is used to fabricate sub-micrometric fiber mats made of a random equimolar poly(lactide-co-glycolide) copolymer (PLGA), whose in vitro hydrolytic degradation kinetics is investigated over a period of 49 days in phosphate buffer at 37 °C. The PLGA mats show a decrease of molecular weight (by GPC) from the very beginning of the experiment, whereas a macroscopic weight loss from the samples is appreciated (by gravimetry) only after 20 days of buffer exposure. The molar mass distribution curves remain monomodal during the degradation experiment suggesting that no acid auto-catalyzed hydrolysis, commonly observed in bulk specimens, occurs in sub-micrometric PLGA fibers. PLGA scaffolds containing Endothelial Growth Factor Supplement (ECGS) were also fabricated by electrospinning, from ECGS-containing polymer solutions. Mesenchymal cells derived from human bone marrow mononuclear cells were cultured in the presence of such ECGS-loaded PLGA scaffolds. Flow cytometry and Differential Interference Contrast microscopy were used to characterize the cell cultures over a 7 day period. The results of AnexinV/PI staining and of intranuclear Ki-67 protein expression show, together with concomitant cell morphology modifications, that growth factors released from the scaffolds support the survival, proliferation and growth of the mesenchymal cells. This result demonstrates that ECGS maintains its bioactivity upon release from the electrospun fibers and shows the versatility of the electrospinning technique.

The morphology and structure of the overlying poly(3-hexylthiophene) (P3HT) layer onto differently silanized silicon oxide has been studied by Atomic Force Microscopy (AFM) and X-Ray Diffraction (XRD) techniques. By increasing the silanizer alkyl chain length, the layer morphology evolves from a filament like to globular needle like as a consequence of the different SAM organization, while the P3HT conformation remains edge-on . For each case the effect of the annealing temperature has been studied. For all the cases a particular attention has been paid to the first thin layers close to the interface P3HT/SiOx. The effect of a polar substituent and presence of aromatic ring has been also studied.

Three different monomers starting from p-(4-hydroxy)benzoic acid and 3- chloro-1-propanol, 4-chloro-1-butanol and 6-chloro-1-hexanol, respectively, were synthesized and extensively characterized by means of 1 H and 13 C NMR, MALDITOF MS and elemental analysis. Subsequently, poly(4-oxyalkylenoxy benzoate)s polymers with different chain length were prepared in bulk starting from the mentioned above monomers, employing Ti(OBu) 4 as catalyst, according to the usual two-stage polymerization procedure. The polymers were characterized in terms of chemical structure, molecular mass and thermal behaviour. T g , T m and the ability to crystallize were found to be affected by the number of methylene groups per repeat unit and the results were explained mainly on the basis of the increment of the chain flexibility.

The problem of dye migration in PE which is of importance for coating and packaging applications was examined with fluorescent colorant C.I. Solvent Yellow 43 as a model of fluorescent dye poorly soluble in PE. These types of dyes are soluble in the PE melt, they show however a strong tendency to crystallize on cooling and to migrate on the surface giving rise to the typical blooming effect. It could be demonstrated by different migration tests that on addition of P(EB)-b-PEO or SEBS block copolymers, having one sequence selectively miscible with PE, the other with the dye, prevent to a very large extent the dye migration and thus its surface crystallization (blooming). This improvement is attributed to the formation, in the PE amorphous phase, of PEO and PS microdomains respectively that are able to solubilize selectively the dye. By fluorescence spectroscopy it could be demonstrated that the dye is selectively solubilized in the PEO microdomains of the P(EB)-b-PEO block copolymer, as well for micelles formed in heptane, as for the blends with PE.

Frontal Polymerization was successfully exploited as an innovative technique for the consolidation of Neapolitan Yellow Tuff, the main volcaniclastic rock of Campania region (Italy). The protocol used and the full characterization in terms of mechanical properties of the resulting consolidated stone are presented here and discussed together with the data obtained by X-ray tomography as a non destructive analytical technique for determining the internal map of the consolidated material. The proposed treatment definitely succeeded from the technical point of view resulting in an enhancement of mechanical properties.

The viscometric behaviour of polyacrylonitrile solutions in dimethylformamide has been examined in dilute and extremely dilute regimes of concentration. For semidilute and concentrated solutions, viscoelastic properties were determined and discussed. The overlap concentration was evidenced as being the crossover of two scaling laws characterizing the entangled and nonentangled solution regimes.

The modification of porous suspension-type polyvinyl chloride (PVC) particles by an in-situ stabilizer-free polymerization/crosslinking of a monomer solution absorbed within the PVC particles is presented. The modifying polymers are polybutyl acrylate (PBA) and polyethylhexyl acrylate (PEHA) crosslinked with ethylene glycol dimethacrylate (EGDMA). The effect of the unique blending procedure on the physical and mechanical properties of PVC has been investigated. The modified PVC characterizations includes polymerization yield, transparency, fracture surface morphology, thermal stability, dynamic mechanical properties, tensile properties, impact resistance and melt rheology. The polymer chains formed are dispersed as a separate phase as observed by scanning electron microscopy (SEM), and two separate glass transitions are observed by dynamic mechanical thermal analysis (DMTA) system, typical of immiscible polymer blends. Mechanical properties of PVC/PEHA blends reveal a substantial increase in impact strength particularly when the blend is crosslinked; however, there is a decrease in the yield stress and elastic modulus. A shift from brittle failure to ductility has been observed in blends of PVC on incorporation of PEHA. SEM studies have been carried out to support these observations.

The sulfonated polysulfone/phosphotungstic acid (SPSU/PWA) composite membranes were investigated for proton exchange membranes. The influence of the interactions between sulfonic acid groups and phosphotungstic acid on the properties of composite membranes was studied in detail. The study showed that special interaction has great influence on the membrane properties. Fourier transform infrared (FTIR) spectroscopy of the composite membranes exhibited band shifts showing a possibility of intermolecular hydrogen bonding interaction between SPSU and PWA additives. SPSU/PWA composite membranes were evaluated for thermal stability, ion exchange capacity, water uptake and proton conductivity. Also the extraction of PWA from the composite membranes and their chemical stability were determined. Thermal analysis of the composites showed that it promotes the decomposition temperature of the sulfonic acid groups with increase in PWA weight content. Though the IEC and water uptake decreased with increase in PWA content, the proton conductivity of the composite membranes increased with increase in PWA content. The proton conductivity of the composites with 5 wt.%, 20 wt.% and 30 wt.% PWA is 2.62×10 -2 , 1.34×10 -1 and 1.66×10 -1 s·cm -1 at 80 o C, respectively.

Pyromellitic dianhydride (1) was reacted with L-leucine ( 2 ) to result in [ N,N' -(pyromellitoyl)-bis-L-leucine diacid] ( 3 ). This compound ( 3 ) was converted to N,N' -(pyromellitoyl)-bis-L-leucine diacid chloride ( 4 ) by reaction with thionyl chloride. The microwave-assisted polycondensation of this diacid chloride ( 4 ) with polyethyleneglycol-diol ( PEG-200 ) and/or three synthetic bisphenols furnish a series of new PEI s and Co-PEI s in a laboratory microwave oven (Milestone). The resulting polymers and copolymers have inherent viscosities in the range of 0.31- 0.53 dl g -1 . These polymers are optically active, thermally stable and soluble in polar aprotic solvents such as DMF, DMSO, NMP, DMAc and sulfuric acid. All of the above polymers were fully characterized by IR spectroscopy, 1 H NMR spectroscopy, elemental analyses, specific rotation and thermal analyses. Some structural characterizations and physical properties of these optically active PEI s and Co-PEI s are reported.

This paper describes the preparation of Epoxy/Urethane (EP/PU) graft interpenetrating polymer networks (g-IPNs) and investigates the effect of EP/PU weight ratio and urethane's prepolymer molecular weight on the mechanical, morphological and thermal properties of the IPN system. Here, g-IPN was prepared by thorough mixing of an isocyanate-terminated urethane prepolymer with an epoxy resin followed by simultaneous curing of the resins. Polytetra hydrofuranate (PTHF), molecular weights (M w ) 1000, 2000 and 3000 g/gmol, was used to prepare urethane prepolymers. EP/PU weight ratios were 75/25, 50/50, 30/70 and 15/85. Disappearance of epoxide and isocyanate functional groups was followed by Fourier Transform Infrared spectroscopy (FT-IR), showing curing of the resins. Differential Scanning Calorimetry (DSC) was used to investigate the glass transition temperature (T g ) of the IPNs. Thermal Gravimetric Analysis (TGA), Dynamic Mechanical Thermal Analysis (DMTA), tensile measurements and Scanning Electron Microscopy (SEM) were used to study thermal, mechanical and morphological properties of the prepared systems. The best mechanical properties were obtained at EP/PU weight ratio 75/25 which also shows a fine and uniformly dispersed morphology. Moreover, at this ratio, with increasing PTHF M w in the urethane prepolymer, the mechanical properties were improved whereas a decrease was observed in T g and thermal degradation temperature of g-IPNs.

Novel electron-acceptor materials based on poly(thienylene ethynylene) derivatives (PTE-BT and PTE-DCNTB) were synthesized and characterized by FTIR spectroscopy. Their thermal, electrochemical and optical properties were investigated. The π-conjugated polymers are soluble in common organic solvents. The maximum UV-Vis absorptions of PTE-BT and PTE-DCNTB in solution are observed at 460 and 390 nm, respectively. The electrochemical band gap was found to be 1.89 eV for PTE-BT and 2.01 eV for PTE-DCNTB. Both polymers are promising as electron-acceptor materials for photovoltaic applications.

The aim of this work is to investigate the properties of the PP/EVOH films for their potential use in the packaging industry. Besides, the barrier properties, the mechanical parameters and the morphology of the PP/EVOH films have been studied as function of their composition and the processing technique used for their manufacture. In these applications, the package is frequently in contact with humidity environments and for this, it is necessary to know how environments with different humidity contents, affect the O 2 permeability of the polymer material. For these reasons, the influence of the moisture in the values of permeability was evaluated too. The data showed that the oxygen transmission rate (O 2 TR) decreased with the amount of EVOH, and if the copolymer mass is maintained constant, the O 2 TR diminished with the quantity of the ionomer in the compositions. Besides, the films obtained by extrusion and following unidirectional stretching, presented better barrier properties to the oxygen molecules than the compression moulded films. When the ionomer is added to the compositions the permeability is reduced even for the films maintained in wet atmosphere. The micrographs obtained by SEM showed that the films have a biphasic structure, where the EVOH particles are dispersed in the PP matrix.

Immobilization of the protein collagen Type I into transparent porous silica matrices produced by the sol-gel process was achieved by using a high concentration of precursor and a low pH. Surface silanol groups interact chemically with the amide and carboxylic groups of the collagen Type I to produce a novel nanohybrid.

Two PA 6/clay nanocomposites, NCN5 and NCN10 with 5 and 10% (wt %) clay, respectively, were prepared by a twin screw extruder. The effects of annealing including solid-state annealing and melt-state annealing on the polymorphic behavior and thermal property of nanocomposites have been comparatively studied as a function of annealing time using Modulated Differential Scanning Calorimetry (MDSC). It was demonstrated that NCN5 and NCN10 exhibit a similar polymorphic behavior when they were annealed in solid-state for different durations. As the annealing temperature was elevated to 245 °C (melt-state annealing), significant differences in thermal behavior and polymorphism between NCN5 and NCN10 could be found. For NCN5, the α structure became the absolutely dominating crystalline phase independent of the annealing durations, for NCN10, however, the formation of γ structure is greatly enhanced and longer annealing time would amplify this phenomenon. Moreover, a low-temperature endothermic peak was observed around 180 °C in both NCN5 and NCN10 samples which was also found to strongly depend on the thermal history.

The rheological, morphological and mechanical properties of LLDPE/PS blends with a combined catalyst, Me 3 SiCl and InCl 3 ·4H 2 O, were studied in this work. The higher complex viscosity and storage modulus at low frequency were ascribed to the presence of graft copolymers, which were in situ formed during the mixing process. From the rheological experiments, the complex viscosity and storage modulus of reactive blends were higher than the physical blends. The dispersion of LLDPE particles of reactive blending becomes finer than that of physical blends, consistent with the rheological results. As a result of increased compatibility between LLDPE/PS, the mechanical properties of reactive blends show much higher tensile and Izod impact strength than those of physical blends.

Graft copolymer of natural rubber (NR) and poly(dimethyl (methacryloyloxymethyl) phosphonate (PDMMMP) (i.e., NR- g -PDMMMP) was prepared and used as a blend compatibilizer in 50/50 NR/EVA simple blends. Influence of various loading levels of NR- g -PDMMMP (i.e., 0, 1, 3, 5, 7, 9, 12 and 15 wt% of NR) on rheological, dynamic, mechanical and morphological properties was investigated. The results showed that the best compatibilization effect was observed in the blend with a loading level of NR-g-PDMMMP at 7 wt%. That is, the highest complex viscosity, tensile strength, elongation at break as well as the lowest values of tension set and tan δ value (i.e., damping factor) were observed. This indicates the highest mechanical strength and the supreme elastic response of the material. Morphological properties of 50/50 NR/EVA blends with any loading levels of NR-g-PDMMMP compatibilizer showed co-continuous phase system. However, in the NR/EVA blend with NR-g-PDMMMP at a loading level of 7 wt%, the finest phase morphology was observed. The 50/50 NR/EVA blend with lower and higher loading amounts of NR-g-PDMMMP compatibilizer exhibited inferior dynamic, mechanical properties as well as larger phase morphologies.

New data on the propagation rate coefficient, k p , of vinyl acetate (VAc) are obtained via the IUPAC recommended method of pulsed laser polymerization - size exclusion chromatography (PLP-SEC) operated at 500 Hz laser repetition rate. An apparent dependency of the experiment’s outcome on the laser pulsing rate is identified with k p being about 25 % larger at 500 Hz compared to 100 Hz. The temperature dependence of k p was determined to fit ln k p = 17.12 - 2621 K/ T ; data is in generally good agreement with literature values when the previous underestimation of k p by 100 Hz laser pulsing experiments is taken into account.

Core-shell modifiers of MB-g-GMA have been synthesized by emulsion polymerization technique. For these modifiers, the core is made up of the crosslinked poly(butadiene) and the shell is methyl methacrylate (MMA) and glycidyl methacrylate (GMA) copolymer. These modifiers were used to toughen poly(butylene terephthalate) (PBT)/bisphenol A polycarbonate (PC) blends. The mechanical properties showed that the addition of 15% MB-g-GMA had a very good influence on the notched Izod impact strength and elongation at break of the PBT/PC blends. DMA results showed PBT was partially miscible with PC and the addition of MB-g-GMA further improved the miscibility of PBT and PC. DSC tests further testified the introduction of MB-g-GMA improved miscibility between PBT and PC. Scanning electron microscopy (SEM) displayed a very good dispersion of MB-g-GMA particles in PBT/PC blend. Transmission electron microscopy (TEM) proved MB-g-GMA particles were enveloped by a thin layer of PC, PBT and PC showed co-continuous structure or dispersed phase which depended on the content of MB-g-GMA. SEM results showed shear yielding of the matrix and cavitation of rubber particles were the major toughening mechanisms.

The aim of this study is the preparation of molecularly imprinted polymers with high selectivity for metotrexate (MTX), a useful antineoplastic drug widely employed in clinical trials. Methacrylic acid, 2-(dimethylamino)ethyl methacrylate and a mixture of them were tested as functional monomers in order to optimize the performance of imprinted materials. The specificity and the selectivity of imprinted polymers was tested by performing rebinding experiments in water at pH 7.4. The best results were obtained by employing both functional monomers in the polymeric feed. In this way, each monomer interacts with complementary functionalities on template molecule, stabilizing the prepolymerization complex and minimizing the repulsive effects (due to the ionization of functional groups) in the rebinding media.

One of the methods of polymeric material modification is based on the irradiation with accelerated ions. Chemical etching of ion tracks in polymers is a method which is widely used in the fabrication of micro/nano-structures with predetermined characteristics. For the present study polyvinyl butyral (PVB) porous membrane was prepared by track-etching technique. Commercially available PVB film was irradiated by 30 MeV energy protons to form latent tracks, and then etched chemically by potassium hydroxide (KOH) with the different normalities. The etching rate of PVB was related to the concentration of etching reagent, temperature and time. The porous size and shape were investigated by scanning electron microscope (SEM) after and before etching. Relationships in between the etching rate and the etching parameters were established from experimental data, and can be used to control the pore size of PVB track-etch membrane. The Pore sizes and their structures were evaluated by optical microscope (OM) and scanning electron microscope (SEM). The results have shown the micro/nano-pores formation in the PVB films. The physico-chemical properties of the irradiated samples were investigated and compared with the un-irradiated one using the FTIR and DSC and DTG systems, as well.

Preparation of superabsorbent hydrogels based on sodium alginate was investigated by mixing aqueous sodium alginate solution and aqueous multivalent amine (ethylenediamine, L-lysine, chitosan) solution, followed by HCl addition. After precipitation in methanol, vacuum drying, and pulverization with mixer, granule products with acid-base interaction were obtained. The preparation condition was investigated by changing the feed amount of amine compound. Among those examined, the highest water absorbency was obtained with the sample for chitosan feed ratio to sodium alginate of 100 mol%, reaching 410 g/g in pure water, 100 g/g in 0.9 % solution, and 80 g/g in 3.5 % NaCl solution. Hydrogels in the present study exhibited good biodegradability irrespective of amine compound.

This work focuses on the preparation and characterization of novel hyperbranched polyimides based on commercially available 4,4,’4’’- triaminotriphenylmethane and pyromellitic dianhydride or 4,4’-oxydiphthalic anhydride. The bi- and trifunctional monomers were reacted in a molar ratio of 1:1 or 2:1 to prepare polyimide precursors (hyperbranched polyamic acids) endcapped with either amino or anhydride groups. The precursors were then transformed into hyperbranched polyimides using thermal imidization. The final products were self-standing films, whose thermal behaviour was characterized by having no weight loss up to 250 ºC and by having glass transition temperatures above 200 ºC. We monitored the permeability of carbon dioxide, organic vapours and water vapour through these membranes. We also compared the properties of these materials with linear polyimides based on 4,4’-methylenedianiline combined with either pyromellitic dianhydride or 4,4’-oxydiphthalic anhydride.

Thermal behaviour of low-density polyethylene (LDPE)/ ethylene-octene copolymer (POE)/ organo-montmorillonite (org-MMT) nanocomposites, prepared via melt compounding were studied by means of differential scanning calorimetry (DSC), thermogravimetry analysis (TGA) and dynamic mechanical thermal analysis (DMTA) techniques. These nanocomposites showed different levels of intercalated structures depending on clay content, blend composition and compatibilization. Addition of polyethylene grafted maleic anhydride (PE-g-MA), as a compatibilizer, improved the intercalation process. The nanocomposites with 5% org-MMT and 5% PE-g-MA showed improved storage modulus and thermal stability in dynamic mechanical and thermal analysis, respectively. The degradation trends of nanocomposites were almost similar to the neat blends in nitrogen environment, but in air atmosphere thermal stability of the nanocomposites increased. The DSC results showed that the org-MMT layers dispersed in the nanocomposites could act as nucleation agents for the crystallization of the LDPE matrix. The results indicated that clay dispersion and interfacial adhesion, and consequently thermal properties of nanocomposites, are greatly affected by addition of PE-g-MA.

A series of cyanophenyl-substituted poly(aryl ether ketone)s (PAEKs) have been successfully synthesized from two new bisphenol monomers, (3,4- dicyano) phenylhydroquinone and (4-cyano) phenylhydroquinone respectively, and the thermal behaviour and the solubility have been characterized. These polymers exhibited high glass transition temperatures and excellent thermal stability. The glass transition temperatures ranged from 173 to 217 o C, and 5% weight-loss temperatures were above 470 o C. The solubilities of these polymers have been remarkably improved in common organic solvents over PEEK and PEN. Some polymers formed transparent, strong, and flexible films, with tensile strength of 106.5-125.2 MPa, Young’s moduli of 2.68-3.20 GPa, and elongations at break of 9- 16 %.

Polyaniline nanofibers with high yield (93%) have been synthesized by an unstirred polymerization of aniline in aqueous acid media with ammonium persulfate as an oxidant in the absence of any template, dopant or surfactant. The morphology, structure and electrical conductivity of the nanostructural polyaniline prepared under different conditions were characterized by means of scanning electron microscopy, FTIR, UV-vis and four-probe techniques. It was found that branched network-like polyaniline nanofibers were prepared without any mechanical stirring, whereas irregular and rodlike structural polyaniline samples were obtained with mechanical stirring under the same reaction conditions. Flowerlike polyaniline microspheres of ca. 3.5 μm in outer diameter, which were constructed with nanostructural polyaniline lamellar by self-assembly process, were synthesized during the polymerization at 0 °C for 72 h. The as-synthesized HCldoped polyaniline nanofibers have good room-temperature electrical conductivity of 5.0 S/cm.

The time dependence of nucleation rate in isothermal crystallization of poly(3-hydroxybutyrate) was experimentally shown, both in heterogeneous and homogeneous nucleation. The time dependence of nucleation rate is one of the important limitations for the applicability of the simplified form of Kolmogoroff- Avrami-Evans model with time independent kinetic characteristics. The presented results are interpreted in terms of non-steady-state cluster size distribution underlying transient nature of nucleation. The relaxation time needed for reaching a steady-state cluster size distribution and thus steady-state nucleation rate is relatively long, exceeding the time of exhaustion of heterogeneities. The relaxation time estimated from homogeneous process was tens of seconds in the temperature range between 83 and 120 o C. Application of Arrhenius law allows estimation of relaxation time in broader temperature range, showing an increase of relaxation time with decreasing temperature.

Bromine-containing methacrylate, 2-(2-bromoisobutyryloxy) ethyl methacrylate (BIEM), had been used in the formulation of acrylic radiopaque cements. The effect of this monomer incorporated into the liquid phase of acrylic bone cement (ABC), on the curing parameters, thermal properties, water absorption, density, compression tests and radiopacity was studied. A decrease of maximum temperature and an increase of the setting time were observed with the addition of the brominecontaining monomer in the radiolucent cement composition. Adding BIEM in radiolucent ABCs composition results in the decrease of glass transition temperature and increase in its thermal stability. The ABCs modified with bromine-containing comonomer are characterized by polymerization shrinkage lower than the radiolucent cement. Addition of bromine-containing comonomer in radiolucent ABC composition determines the increase of compressive strength. The ABCs modified with brominecontaining comonomer proved to be radiopaque.

The change in the phase diagram of polymer mixtures under flow is an important issue since flow may promote mixing or demixing of the phases in a polymer mixture. This work, compared to previous studies, presents a different approach with special attention to the rheology of polymer solutions and flow conditions. Different approaches including Marrucci's approach in calculating stored elastic free energy (ΔGE) have been reviewed. Marrucci’s equation is obtained based on a fundamental analysis of polymer chains microstructure. The new approach introduces the proper viscoelastic constitutive equations to estimate ΔGE. Selecting the appropriate rheological model is essential to correctly estimate the state of stress and deformation rates due to the flow. Moreover, the parameters of viscoelastic constitutive equations were defined, from the microstructural viewpoint, as functions of composition and temperature in semi-concentrated regions. Finally, flow induced change in the phase diagram of polymer solutions is predicted for a well-defined flow condition (constant shear rate and stress), and the results are compared with the previously reported experimental observations of mixing and demixing.

To improve the dispersion stability of carbon black (CB) in aqueous media, an anion vinyl monomer, namely potassium 4-vinylbenzoate (K-4VBA) was polymerized and coated on to the CB particles through ultrasonically assisted radical polymerization. FT-IR was used to detect the presence of poly(K-4VBA) on the CB surface. The TGA results indicated that the polyelectrolyte contents of the CB particles could reach 77.5% in weight. The TEM studies revealed that the surface morphologies for the coated polyelectrolyte. Combined aqueous electrophoresis and DLS studies confirmed that these polyelectrolyte modified CB particles had pH-dependent colloid stabilities, as expected. The modified particles were colloidal stable at high or neutral pH, but became aggregated at low pH.

Polypropylene oil-absorption fibre (PP-g-BA) was prepared by radiationinduced graft polymerization of butyl acrylate (BA) onto polypropylene (PP) using divinylbenzene (DVB) as cross-linking agent. The original and grafted PP fibres were characterized by Fourier transform infrared (FT-IR) spectrometer and Scanning Electron Microscopy (SEM), and the result indicated that butyl acrylate was successfully grafted onto PP fibre. The factors that influenced the grafting degree of PP were discussed, such as the concentration of monomer and crosslinking agent. When the concentration of DVB was 2% and the concentration of BA was 10%, the maximum grafting degree reached 20.53%. The oil absorption properties of PP and PP-g-BA fibre were investigated and the results showed that the maximum adsorption capacity of PP-g-BA reached 19.74 g/g for toluene and 18.8 g/g for kerosene. Simulating absorption in the oil floating on the surface of water showed that the oil could be absorbed quickly and completely in three minutes. PP-g-BA exhibited quicker adsorption rate and higher adsorption capacity than PP fibre did.

Hydrogels have potential applications in many fields, but the poor mechanical strength has limited their further development. In this article, we designed a simple route to high-strength interpenetrating polymer network (IPN) hydrogel from polyacrylamide (PAAm) and poly(vinyl alcohol) (PVOH). The highest tensile strength and elongation were 2.4 Mpa and 4300 %, respectively. It was found that the hydrogel strength depended on the chemical crosslinking, physical entanglement and PVOH precipitates. Because of the hydrogen bonding interactions and self-crosslinking, the structure of PVOH transferred from crystal to amorphous. PVOH precipitates scattered in the crosslinked PAAm matrix which dispersed the stress and improved the hydrogel toughness. The simple method is versatile in synthesizing high-strength IPN hydrogels using many kinds of polymer species.

The aim of this study was to investigate the effects of silver nanoparticles (Ag-NPs) concentration on surface of polyurethane microporous films. The Ag-NPs have a diameter between 1.74-10 nm and were synthesized in the polymer matrix. The effects of Ag-NPs at the surface of polyurethane (PU) microporous films were investigated by means of attenuated total reflection Fourier infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM) and contact angle measurements. The mechanical behavior of PU films vs Ag-NPs concentration was also studied. The Ag-NPs induce changes in the PU surface structure, wettability properties, topography and mechanical properties. These phenomena may be due to interactions between Ag-NPs and urethane groups which form new structure urethane-silver-urethane with a specific morphology and the nanostructuring of the surface by means of metallic nanoparticles.

Molecular mechanics computations and simulations involving the Mopac assisted SCF LCAO MO ZINDO1 method were performed for complexes of ɑ-Dglucose with Co(II), Cu(II), Fe(III), Mn(II) and Ni(II) acetates, chlorides and nitrates. The computations resulted in the following findings: Usually the saccharide ligand completely repulsed water molecules from the inner coordination sphere of the central metal atoms. The complexes with Fe(III) acetate and chloride and nitrates of Co(II) and Cu(II) constituted random exceptions having some water molecules in that sphere. The oxygen atom of the 3-hydroxyl group in ɑ-D-glucose (the O3 atom) was the preferred coordination site. The stability of complexes declined as the primary saccharide chain composed of one ɑ-D-glucose was extended by subsequently 1→4 bound ɑ-D-glucose mers. Also such chains coordinated to the central atoms through the O3 oxygen atom. Analysis of the increment of increase in the heat formation with each subsequent ɑ-D-glucose mer in the saccharide chain might suggest that such chain forms chelates with the central metal atom. With CuCl 2 first and third ɑ-D-glucose mers were involved in the chelate formation, whereas in case of CoCl 2 the first and fourth D-glucose mers were involved.

Polyacrylamide “water-in-water” emulsion was regarded as a new generation of water-soluble polymeric materials and has attracted much attention from both academia and industry because of its environmentally-friendly character. Anionic polymeric “water-in-water” emulsions prepared by dispersion polymerization of acrylamide (AM) and sodium acrylic acid (NaAA) in mixed solution of Na 2 SO 4 and (NH 4 ) 2 SO 4 are reported in this paper, and the parameters influencing polymerization and the final dispersion stability, including, N 2 flow rate, chain transfer agent content, inorganic salt content, and the molar ratio of AM to NaAA were examined and opitimized. It was found that the intrinsic viscosity of resulting copolymers decreased as the N2 flow rate and CTA concentration increased, and the resultant dispersions with 27 % ∼ 28 % inorganic salt have regular particle shape, lowest particle size, better flowability and storage stability. The salt level in the reaction system would also dominate the time that the dispersion formed, and the ratio of AM to NaAA would influence the total monomers conversion and polymerization rate.

Nano-Fe/carbon fiber/ Low-density polyethylene (LDPE) composites were prepared by melt compounding. The electromagnetic shielding properties of nano-Fe/CF/LDPE composites as a function of nano-Fe mass content were investigated. The data of DC electrical conductivity evidence percolation behavior of the composites, and percolation threshold descends with the increase of nano- Fe. When the CF/LDPE composites reach the percolation threshold ( pCF =0.10), “double percolation” appears in the nano-Fe/ CF/LDPE composites as continuously adding nano-Fe into the CF/LDPE composites, and the percolation threshold of the “double percolation” is 0.10 mass fraction of CF and 0.08 mass fraction of nano-Fe, which result in at least 10 3 orders of magnitude greater than that of CF/LDPE composites. The data of Initial DC permeability μ r, coercivity Hc , saturation magnetization Ms and residual magnetization Mr of nano-Fe/CF/LDPE composites at the magnetic field intensity between -2500 G and 2500 G enhance with increasing addition of nano-Fe. The value of relative permeability decreases as the loading of nano-Fe is increased from 0.04 to 0.19 mass fraction in frequency ranges of 300 KHz-100 MHz. The EMI SE in frequency ranges of 300KHz-100MHz increase with the addition of nano-Fe, and mechanism of electromagnetic shield for nano-Fe/CF/LDPE composites is compound shielding mechanism with reflection loss R and absorption loss A . Absorption loss A increases significantly with increasing addition of nano-Fe from 0.04 to 0.19 mass fraction, and increasing trend of reflection loss R slow down as mass fraction of the fillers reach percolation threshold.

Three difunctional benzoxazine monomers bis (3,4-dihydro-2H-3-phenyl- 1,3-benzoxazinyl) methane, (abbreviated as BF-a), bis (3,4-dihydro-2H-3-phenyl-1, 3-benzoxazinyl) isopropane, (abbreviated as BA-a), bis (3,4-dihydro-2H-3-phenyl- 1,3-benzoxazinyl) biphenyl, (abbreviated as BP-a) were successfully synthesized via phenol (bisphenol A, 4,4’-Biphenol, bisphenol F), aniline and paraformaldehyde. Their structures were identified by 1 H NMR and FT-IR. The monomers were thermally treated at 200 oC for 2 h in nitrogen to give corresponding prepolymers. The thermal properties of the monomers were investigated by TGA under nitrogen atmosphere. The thermal properties of the prepolymers were investigated by TGA under nitrogen and air atmosphere. It was found that the monomers of BF-a and BA-a showed lower melting points and exhibited wider processing windows than BP-a. The prepolymer from BP-a showed good thermal stabilities, compared with the prepolymers from BF-a and BA-a.

HDPE was analyzed after being submitted to cryogenic mechanical milling (CMM) by X-ray diffraction (WAXS), polarized light microscopy and differential scanning calorimetry (DSC). After CMM, besides the known phase transformation of the orthorhombic PE crystals into the monoclinic modification, slight changes in the melting and crystallization behavior as well as an unexpected increase in crystallinity were observed. The observed results can be explained by assuming a solid/solid phase transition as the responsible mechanism.

Free radical grafting copolymerization of butyl acrylate (BA) onto polypropylene (PP) matrix was investigated using supercritical CO 2 as a swelling agent and carrier solvent. The monomer BA and initiator AIBN were first dissolved in supercritical CO 2 , and then these small molecules were diffused into the grafting zones of PP matrix. As grafting reaction temperature (about 80 °C) was far below the melting point, PP was modified in the solid phase. The effects of different experimental conditions such as soaking time and temperature, supercritical CO 2 pressure; monomer and initiator concentration; PP particle diameter; solid phase grafting reaction time and temperature on grafting percentage were studied. Fourier transform infrared spectroscopy (FTIR) results and gel content experiment prove that the monomers were indeed grafted onto PP chains. Scanning electron microscope (SEM) analysis of the grafted sample indicates that the grafting branches PBA were homogeneously distributed onto the surfaces and micropores of PP particles. Thermal gravimetric analysis (TGA) results show that the grafted samples had a higher onset thermal degradation temperature and a lower weight loss at a particular temperature than pure PP. The water contact angle of PP-g-BA decreased from 98° to 72°, indicating the polarity and hydrophilicity of PP were improved effectively. The melt flow rate (MFR) and mechanical analysis results show that the grafting sample remained its versatile physical properties though introducing the grafting BA branch chain. This is prominent when it was compared with normal solid grafting product.

The coagulation properties of cellulose from cellulose//NaOH/thiourea/ urea/H 2 O solutions were investigated with the goal of determining the optimal coagulation conditions for the spinning of cellulose fibers. The present study was concentrated on the effect of the coagulation variables upon the coagulation process. It was observed that at the start of the process, the thickness of the solidified layer ε was proportional to the square root of time. Model experiments were performed on gelled solutions of cellulose/NaOH/thiourea/urea/H 2 O in a coagulation bath to determine the coagulation rate,e / t , and mass transfer rate difference between the solvent and the coagulant, Dk . The influence of coagulant compositions, coagulation time and temperature, and cellulose concentrations on coagulation rate and mass transfer rate difference performed on cellulose samples had been demonstrated by microscopic observations, which was important for understanding and controlling the process of cellulose shaping from NaOH/thiourea/urea/H 2 O solutions. The data were analyzed by means of the diffusion model based on Fick's law, thereby depicting the mechanism of the coagulation process, which could be described as a two-phase separation, namely a cellulose-rich phase in the coagulated layer and a cellulose-poor phase in uncoagulated layer.

Water-in-oil emulsions having their aqueous internal phase gelled with starch were prepared and investigated. They were the primary emulsions required for the preparation of double w/o/w emulsions that could encapsulate hydrophilic materials inside the internal aqueous gel. The emulsification could be achieved at high temperature in spite of the high viscosity of the aqueous phase; the internal phase gelled upon cooling to room temperature. The high viscosity of the aqueous phase limited the possible concentration range of starch in the aqueous phase. The presence of starch made the surfactant demand larger for both the emulsification and the stabilization of the w/o emulsions. The larger the starch content, the larger the amount of required surfactant. One reason for the high surfactant demand was the high viscosity of the aqueous phase containing starch. Another cause of high surfactant demand was disclosed and it appeared that predominantly the interactions of the nonionic surfactants with starch retained the former inside the aqueous phase. The immobilized amount of surfactant had to be compensated by a supplementary concentration. Experimental evidence of the interactions between starch and the nonionic surfactants was given by interfacial tension measurements. Lastly, w/o/w double emulsions were prepared using the gelled w/o emulsions and a model hydrophilic molecule (caffeine) was encapsulated inside the internal gelled aqueous phase. The release rate of caffeine from the internally gelled double emulsions was slower than for the non-gelled emulsions, demonstrating the efficiency of the encapsulation and the possible control of the delivery.

Plastics are being preferred in almost all possible applications of materials. Several new applications including optical devices are being developed using plastics replacing conventional materials like inorganic glass etc. For the optical applications, the most important properties of plastics essential for their desired performance include refractive index, Abbe number, optical clarity, etc. The biggest challenge in developing suitable materials for optical applications has always been to meet the criteria of high refractive index along with a high Abbe number. Normally, if the refractive index increases, the Abbe number automatically decreases. The researchers have tried several approaches to deal with this typical challenge without which it is not possible to develop novel optical plastics. Presently the most popularly known optical plastics includes polymers such as polymethacrylates, polyurethanes, polycarbonates, polystyrene and diethylene glycol bis allyl carbonate. The latest material of high refractive index plastics with a refractive index of 1.67 belongs to the polythiourethanes chemistry. Several approaches are being tried world over, to develop materials of high refractive index. One of the approaches being pursued for enhancement of refractive index of existing monomers pertain to the incorporation of metals or metal salts in the matrices. The other commonly tried but difficult to achieve approaches pertain to the preparation of nanoparticles or nanocomposites.

Carbon black (CB)-filled polytetrafluoroethylene (PTFE) composites were prepared by compact molding of a dry-mixture of CB and polymer powders followed by a sintering technology. The composites show a very low percolation threshold about 5 vol. %, which can be attributed to the segregated distribution of CB in the interfacial regions of PTFE particles. The PTFE/CB composites exhibit a high PTC transition temperature (>300 0 C), high PTC intensity (3.5) and no NTC effects. The absence of NTC effect of the composites was attributed to the extremely high viscosity of PTFE at temperatures above its melting point, which restricts the migration of CB particles and prevents the formation of new conductive networks.

The cellulose nanowhiskers (CNW) are of imminent importance in the development of ecofriendly green material for environment. Morphological study of their structure was carried out after extraction from grass. The controlled alkali and acid hydrolysis after soxhlet extraction of bleached fiber in ethanol and water provided a mixture of micro/nano fiber which can be further converted into CNW by mechanical treatment. Width of obtained CNW were found to be ~10-65 nm with length of several nanometers as evidenced by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The changes in dimensions during alkali treatment, bleaching and acid hydrolysis of grass exhibited an interesting architecture and clarify the phenomenon of separation of nano level fibrils from the matrix of hemicellulose and lignin which starts after swelling of fibers and opening from middle followed by splitting from each other. The nanofibers were embedded in the matrix surrounded by amorphous layers. The size of fibers was directly associated with the extent of treatments. The crystalline part of fiber was intact during hydrolysis which must be attributed to easy removal of amorphous region by penetration of hydronum ions from acid. The results of SEM and TEM were correlated with the Scanning Ion Microscopy (SIM) which showed a direct evidence of breaking of thick fiber strands resulting in the formation of sharp edged crystalline entities composed of cellulose crystals.

The well-known key problem with concrete is that its compressive strength and the compression modulus are insufficient for a variety of applications. Our polymer concrete (PC) consists of an unsaturated polyester resin as the polymeric matrix, silica sand as the inorganic aggregate, plus atactic polypropylene (PP) fibers. A further property improvement can be achieved by gamma irradiation and we apply here two methods. The first method consists in irradiation of PP fibers first and then adding them to the PC. The second route consists in irradiation of PC after inclusion of PP fibers. Along both routes we have applied the radiation at dosages ranging from 5 to 150 kGy. In the second route irradiation of silica sand results in larger contact areas of surfaces with PP fibers and with the polyester resin-as seen in scanning electron microscopy. The second route provides compressive properties which is better by a factor of two or three (depending on the irradiation dose) than the first one.

Electrospinning of solutions of polyacrylonitrile in dimethylformamide (PAN/DMF) were performed under different voltages at different constant feed rates and the jet electric current was measured. The effects of applied voltage, feed rate and solution conductivity on jet electric current and fiber diameter were investigated. The results showed that the feed rate had no effect on jet current and fiber diameter, whereas by increasing the applied voltage and solution conductivity, both the jet current and fiber diameter were increased.

The present paper deals with the graft copolymerization of acrylonitrile (AN) onto Saccharum cilliare fiber in air in the presence of ferrous ammonium sulfate - potassium persulphate (FAS - KPS) as redox initiator. Various reaction parameters such as solvent, time, temperature, pH and concentration of monomer and initiator were optimized in order to get maximum graft yield (69 %). Raw fiber and its graft copolymers with AN were then subjected for evaluation of different properties. Characterization of the graft copolymers was carried out with Scanning electron microscope, Fourier transform infrared spectrophotometer and X-ray diffraction studies (X-RD).

This work deals with the study of the processability of blends based on PA6 and NBR. The aim is to achieve reduced PA 6 melting temperatures in order to avoid degradation of the NBR phase during processing. The effect of different additives in PA has been studied. For this purpose PA6 was blended with nonylphenol, EVA 18, EVA 33 and EVAMA. Among several masterbatches based on PA6; the sample containing 5% of EVAMA presented the best combination of processability and mechanical properties. The influence of additives in the processing behavior, crystallinity of the PA6 phase, mechanical and physicochemical properties are discussed in the present work.

Narrow disperse poly(styrene- co -divinylbenzene) microspheres were prepared by precipitation polymerization using acetonitrile/n-butanol mixture as the reaction medium and 2,2’-azobis(2-methylpropionitrile) (AIBN) as initiator. The resulting particles have smooth surfaces due to the absence of any additional stabilizer. Effects of the reaction parameters such as n-butanol fraction in the reaction medium, monomer and initiator concentration, and divinylbenzene content were investigated. It was found that the particle size increased with an increasing concentration of monomer and initiator, while the uniformity was kept constant. The number-average particle diameter ranged from 2.36 to 1.63 μm and decreased with an increasing divinylbenzene concentration. In addition, the uniformity was enhanced as the concentration of divinylbenzene increased. On the basis of the DSC and TGA data, the microspheres prepared by the precipitation polymerization possessed a highly crosslinked structure and the thermal stability improved with the DVB concentration.

Highly soluble and optically active aromatic polyesters (PE)s containing phthalimide and flexible chiral groups were prepared with moderate molecular weights by step-growth polymerization of diacid monomer containing pendant 4- [(2L)-phthalimidylpropanoylamino)benzoyl group with several aromatic diols, in a system of tosyl chloride, pyridine (Py) and N , N -dimethylformamide (DMF) to give a series of new optically active PE s with good yield and moderate inherent viscosity ranging from 0.28 to 0.48 dL/g. The aim of this work was to obtain novel optically active PE s that was more soluble in common organic solvents while maintaining the high thermal stability. All polymers derived from such a diacid and aromatic diols were highly organosoluble in solvents like N -methyl-2-pyrrolidinone, N , N dimethylacetamide, DMF, Py, dimethyl sulfoxide. Thermogravimetric analysis data showed that these PE s are thermally stable, with 10% weight loss being recorded above 400 °C and showed good thermal stability associated with high glasstransition temperatures above 200 °C as measured by differential scanning calorimetry. All of the above polymers were characterized by FT-IR and specific rotation techniques and some of them were also characterized by 1H-NMR and elemental analyses methods.

We have studied nine thermoplastic vulcanizate elastomers (TPVs) in four series: as made, after accelerated aging, after γ irradiation, after both irradiation and aging. The materials exhibit two glass transitions, one seen in crosslinked regions and the other in un-crosslinked amorphous regions. Three techniques of determination of glass transitions have been used and the results compared, all three based on dynamic mechanical analysis (DMA): as a peak in the loss modulus E’’; as a peak in tan δ; and as the midpoint of the rapid decrease in the storage modulus E’. We recommend the last method for both fundamental and practical reasons.

Physical and mechanical properties of four series of chemically and thermally stable sulfonated copolyimides as ion-conducting ionomers for application in fuel cell membrane, depending on chemical structure of diamine monomers were studied. The physical and mechanical properties of solid polymer membranes including thermal stability, mechanical strength, water uptake, stability in water, crystallinity and morphology were evaluated. All the polymers were thermally stable. The XRD analysis and SEM micrograph revealed that the polymers were almost amorphous and hydrophobic-hydrophilic phase separation in polyimide did not occur. Use of flexible monomers such as 4,4'-oxydianiline (ODA) and 4,4'-(4-aminophenoxy) diphenylsulfone (APDS) in the hydrophobic sequences increased the plastic behavior compared to rigid polymers prepared from 4,4'-(5- amino-1-naphthoxy) diphenylsulfone (ANDS) and m-phenylenediamine (m-PDA). It was concluded that the properties of polymeric films were strictly dependent on chemical composition of monomers and molecular weight of copolymers.

Polyacrylonitrile/Soy protein isolate/polyurethane (PAN/SPI/PU) blends were prepared in dimethylsulfoxide (DMSO). The compatibility and interactive properties of PAN/SPI, SPI/PU, and PAN/PU blend systems were studied using dilute solution viscometry and phase contrast microscopy. It was found that PAN/SPI and PAN/PU were immiscible systems, but that there was an attractive interaction between them. However, the SPI/PU was an almost miscible system. To improve compatibility, the main product of graft copolymerization of acrylonitrile and SPI (AN-g-SPI) and the alkaline hydrolysis polyacrylonitrile (HPAN) were used as compatibilizers. The results showed that the mechanical properties of both the PAN/SPI and PAN/SPI/PU systems were significantly improved.

A high dielectric permittivity nanocomposite based on poly(vinylidene fluoride) (PVDF) and organically modified clay is reported. The present work aims to study the effect of clay on dielectric behavior of PVDF. The dielectric permittivity study shows a remarkable enhancement in the permittivity of nanocomposites in the low frequency region. The obtained permittivity values fits quite well to the prediction of dielectric permittivity from Vo-Shi model, which takes contribution of interface to permittivity into account. This enhanced permittivity in nanocomposites is attributed to the presence of interfacial polarization. The interface effect is further studied with cole-cole plot analysis. The dielectric loss study of pristine PVDF shows two relaxations associated with segmental (glass transition relaxation) and crystalline chain relaxation. However in the PVDF/Clay nanocomposites crystalline relaxation peak disappears which is attributed to the formation of the β phase in PVDF/clay nanocomposites.

Poly(N-isopropylacrylamide) (PNIPAm) gel beads were prepared by water in oil (w/o) suspension polymerization using aqueous acetonitrile to dissolve the monomer phase, toluene or cyclohexane as the continuous phase and ethyl cellulose (EC) as the stabilizer. The beads were analyzed by FT-IR and their morphology was investigated by optical and electron microscopy. The advantages of this novel synthetic method for PNIPAm preparation include efficient polymerization and mild experimental conditions, as well as the formation of spherical and relatively uniformly sized particles. The microgels were then evaluated for their efficiency to absorb fluorescently labelled hepcidin. The beads were found to rapidly capture the target peptide from neutral aqueous solutions. Notably, bovine serum albumin (BSA) did not bind to the polymer beads at the cross-linking ratio used; therefore, size-exclusion properties may be controlled by finely tuning monomer to cross-linker ratio and/or monomer concentration during polymer design. The route could potentially be useful for diagnostic, drug delivery or peptide immobilization, as well as for the molecular imprinting of peptides and proteins.

Electrospinning of emeraldine base polyaniline/polyacrylonitrile (PANI/PAN) blends with different composition ratios were performed using Nmethyl- 2-pyrrolidone (NMP) as solvent. The blends were electrospun at various electrospinning temperature and electric fields. Morphology and fibers diameters were investigated by scanning electronic microscopy (SEM). The average diameter of nanofibers and their distributions were determined from 100 measurements of the random fibers with image analyzer software (manual microstructure distance measurement). Electrical conductivity of the prepared mats was characterized using standard four point probe method. The fibers with diameter ranging from 60 to 600 nm were obtained. The PANI/PAN blends containing up to the PANI content of 30% could be electrospun into the continuous fibrous structure, although pure PANI solution was not able to be electrospun into the fibrous structure. Average of fiber diameter decreased with increasing PANI content and electrospinning temperature. The electrospun PANI/PAN fibers at 50 °C and 75 °C showed smaller diameters with much better uniformity than those electrospun at 25 °C. The electrical conductivity of the mats increased with the increase of PANI content in the blend with percolation threshold of 0.5%.

A series of hyperbranched poly(amine-ester) polyols were synthesized by the polycondensation of N,N-diethylol-3-amine-methylpropionate [prepared by the Michael addition reaction of methyl acrylate (MA) with diethanolamine (DEA)] as an AB2-type monomer with trimethylol propane (TMP) as the core moiety, proceeding in one-step procedure in the melt with p -toluenesulfonic acid ( p -TSA)as catalyst. The Michael addition reaction and polycondensation behaviors were systematically investigated, in an effort to optimize the reaction conditions, respectively. Optimum parameters for addition reaction: at MA/DEA ratio of 2:1 for 4 h at 35 °C, adding MA to DEA, using methyl alcohol as solvent; and for polymerization: dosage of p -TSA was 2 wt % (based on total weight of AB2-type monomer and core) for 4~5 h at 120 °C, adding monomer to core. The obtained monomer and polymers were characterized by Fourier transform infrared spectroscopy (FTIR), 1 H-NMR spectroscopy and gel permeation chromatography (GPC). It was suggested that the hyperbranched poly(amine-ester) polyol formed via a mechanism of a combination of transesterification and addition reactions. The thermal stability, solubility and surface activity in aqueous solution of the polymers were also examined.

The ionic liquid of 1-allyl-3-ethylimidazolium chloride ([AEIM]Cl) was synthesized and its chemical structure was confirmed. Dissolution of microcrystalline cellulose (MCC) in [AEIM]Cl by microwave heating method was researched. Acrylamide (AM) was grafted onto the dissolved MCC with initiator in [AEIM]Cl and aqueous medium respectively. The effect of temperature, initiator and its dosages on monomer conversion and grafting efficiency was studied. The results showed that [AEIM]Cl was a good solvent for MCC and dissolution rate was the highest (28.8%) when the MCC pretreated with 15% NaOH under the high pressure. Graft copolymer prepared by AM and MCC in [AEIM]Cl had higher monomer conversion and grafting efficiency than in aqueous medium. The best condition for preparing graft copolymer was that potassium persulfate was used as initiator with the dosage of 1g/L under the temperature of 45 °C-50 °C. Spectra of FT-IR had proved that AM was grafted onto MCC. The thermal stability of MCC improved after grafting, and the crystal form was destroyed thoroughly.

A simple and facile approach to fabricate PVP fibers by wheel-spinning technique was investigated. Poly(vinyl pyrrolidone) sol (PVP, M w =1,300,000, 6-14 w% in ethanol) was used as the candidate polymeric material. It was demonstrated by a rotating wheel with the speeds of 18.84, 15.70 and 12.56 m/s, respectively, PVP fibers can be drawn with diameters ranging from under 200 to over 2 μm and controlled by changing the rotating speed and sol concentration. The morphologies of the wheel-spinning fibers were observed by electronic scanning microscopy (SEM). The nanofibers obtained by this technique are long, straight and smooth, and the fabricated apparatus is simple.

Transient elongational rheology of PP is investigated experimentally. A specifically designed fixture consisting of two drums mounted on a TA Instruments ARES rotational rheometer was used to measure the transient uniaxial extensional viscosity of two commercial grades polypropylene in the molten state. The Hencky strain was varied from 0.003 to 2 s -1 and the temperature was fixed at 180 oC. The measurements show that the steady state elongational viscosity was reached at the measured Hencky strains for polypropylene. Eslami and Grmela have recently introduced a reptation diffusion term arising from the intermolecular chain forces into the rigid FENE-P dumbbells model. The same approach has been used in this study to interpret the transient rheological data in both shear-free and simple shear flows.

Among different natural and non-corrosive products paraffin wax and camel fat are selected as phase change materials (PCM). These PCMs are applied to glass, polyester/viscose and wool/polyester woven fabrics. To examine their efficacy, their thermal behavior in a condition similar to the actual end uses is measured. Chemical nature and thermal properties of the PCMs are measured by Fourier transform infrared spectroscope and differential scanning calorimeter. A relation based on the principle of heat transfer is used to determine the temperature of a thermometer covered by fabrics loaded with PCMs. A simple exponential relation explains the experimental results. For glass and polyester/viscose fabrics use of these PCMs leads to substantial delays in the temperature changes. The important parameters for the evaluation of the products are discussed.

Highly alternating CO 2 -cyclohexene oxide copolymer, namely poly(cyclohexene carbonate) (PCHC), considered potentially to be microelectronic sacrificial material, was successfully synthesized by copolymerization of cyclohexene oxide and CO 2 in the presence of SalenAl(O i Pr) catalyst. The obtained highly alternating PCHC copolymer were determined and proven to have superior thermal decomposition properties decomposing completely at 350 o C by thermogravimetric (TG) analysis under dynamic conditions. The thermal decomposition kinetics of the obtained PCHC was investigated by a different kinetic method using data from TG analysis. Based on the analytical, kinetic parameters were calculated and kinetic model of pyrolysis was proposed. TG-IR, Py-GC/MS, IR and 1H NMR techniques were applied to investigate the decomposition process. Based on Py-GC/MS and TG-IR techniques, carbon dioxide, 1,3-cyclohexadiene, cyclopentanecarboxaldehyde, cyclohexene oxide, cyclohexanone and trans-1,2- carbonyldioxycyclohexane were identified as thermal decomposition products of PCHC. The solid residues of the PCHC with 25% ether linkages decomposed at 200, 250, 300, 350 o C as determined by IR and 1 H NMR. The results demonstrated that the carbonate content of the solid residues decreased gradually at elevated heat-temperatures and at 350 o C only few polyether linkages were observed.

In acidic media, poly(styrene-methacrylic acid)/MCM-41 [P(St- MAA)/MCM-41] core/shell microspheres were synthesized using monodisperse P(St-MAA) particles contained in soap-free emulsion and cetyltrimethylammonium bromide as co-templates by adsorption self-assembly method. The effects of P(St- MAA) composition on shell structure of the core/shell microspheres were investigated. The morphology and composition of P(St-MAA)/MCM-41 microspheres were characterized by TEM, XRD and FTIR. The results show that the ordering degree of MCM-41 shells increased as the molar ratio of MAA to St increased. When n(MAA)/n(St) is 0.2, the average diameter and the shell thickness of nanocomposite microspheres are about 170 nm and 20 nm, respectively.

The aliphatic polyesters: polylactides (PLA), polyglycolides (PGA), poly( -caprolactone) (PCL) as well as their copolymers especially, poly(lactide-coglycolide) (PLGA), poly(vinyl alcohol) (PVA), chitosan, dextran and starch occupy first place among biodegradable, biocompatible and non-toxic polymers. PVA, with different molecular weights, hydrolysis degree, tacticity, crystallinity, and due to the abundance of pendant hydroxy groups in the backbone is capable of several grafting and cross-linking. The present study concerns the synthesis of graft copolymers poly(vinyl alcohol) with lactic acid (LA) and aspartic acid (Asp). The modification reaction of poly(vinyl alcohol) with lactic and aspartic acid was achieved by solution polycondensation using dioxane/water (3/1) as solvent mixture, different molar ratios PVA/LA/Asp and manganese acetate as catalyst: Mn(CH 3 COO) 2 4H 2 O. The copolymers were characterized by FTIR, 1 H-NMR, thermal stability (DSC, TG), elemental analysis, wide angle X-ray diffraction (WAXD). The average particle size and zeta potential for aqueous dispersions of copolymers, solubility in organic solvents and biodegradation testing on agar-agar medium inoculated with a fungus Chaetomium globosum class MO5 stock, were studied.

The rheological properties of the aqueous solution of 1H,1H,11Hperfluoroundecyl acrylate -modified poly(acrylic acid) were studied. It was found that the solutions show different viscosity dependence on shear time at different pH and shear rates. At lower pH and moderate shear rates, the viscosity of the solutions shows a great increase with time. At pH 5.0 and above, it exhibits thixotropy at any shear rate, i.e., the viscosity decreases with time at constant shear rates. If the shearing stops, the viscosity of the solutions can be recovered to some extent. These phenomena are interpreted to be due to the intermolecular hydrophobic association: the construction of the association leads to an increase of the viscosity, the destroying of the association leads to a decrease of the viscosity. The pH-induced conformational change and the shearing-induced chain elongation jointly influence the intermolecular hydrophobic association.

It is true that the developments in material sciences along with the improvements in various aspects of technology involved in transforming materials into products, over the years, have been responsible for making many of the impossible-looking devices possible. It is also a fact that the demand for a new, improved and better material has never ended; in fact it has been increasing to a greater degree and with bigger dimensions than ever before, especially in recent times. As a matter of fact, for certain advanced applications, the need for efforts to have new materials can never be over emphasized; for example, in the area of biomedical devices such as intraocular lens (IOL). The advances in the field of bio-medical applications require the materials of high quality meeting stringent norms of performance. For implants such as the ones like IOL used for correction of vision of the eyes, besides the quality and performance of materials, biocompatibility is an issue of major concern. The material scientists have been working on the development of materials for IOLs targeting the needs arising out of the developing countries. The challenges include not only to bring down the cost of the materials used for IOLs but also to increase the biocompatibility of IOLs. For making the development process easy and bringing the state-of-the- art of knowledge to those looking for new materials, it is thought necessary to review various facets of IOLs in the present paper. Not only the aspects related to the recent developments in biomedical devices of eye care but also related to the properties of available materials vis a vis the deficiencies in properties of existing materials have been covered in this review. The aim has been to bring out the gap areas at various levels of process of product chain starting from the monomer to polymer, blank to IOL, insertion of IOL into eyes to life cycle of IOLs, mainly to provide certain possible and feasible leads to meet the challenges of making new and more biocompatible materials.

The influence of various additives on poly(ether-urethane) UV stability is evaluated. The extent of the photo degradation has been studied by FTIR spectroscopy. The photo-stabilizer 2-hydroxy-benzophenone decreases the photooxidation on both hard and soft segment, whereas the effect of the phenolic antioxidant 2,6-di-t-butyl-4-hydroxytoluene is more significant on the soft segment. However, the effect of the nickel chelate, 2,2’-thiobis(4-t-octylphenolate)-nbutylamine of nickel, depends on the polyurethane nature.

The compatibilization effects provided by different amines in the synthesis of polypropylene/amine modified montmorillonite clay nanocomposites (PP/ A-MMT) were studied. Nanocomposites were prepared by melt processing using a twin-screw extruder, by compounding maleic anhydride grafted polypropylene (PPgMA) with MMT modified with three different amines: ethanolamine (EA), hexamethylenediamine (DA6) and 1,12-diaminododecane (DA12) to form amine modified montmorillonite "A-MMT". FTIR characterization confirmed the formation of characteristic amide linkages and X-ray confirmed the intercalation of PPgMA between the silicate layers. X-ray, scanning electron microscopy with transmission modulus (STEM), thermogravimetric analysis (TGA), rheological properties plus mechanical properties were used to characterize those nanocomposites. X-ray diffraction patterns of the composites using A-MMT showed 001 basal spacing enlargement with good clay exfoliation-intercalation compared with the natural MMT (Na-MMT). The DA12 modified MMT showed the greatest increase in basal spacing. TGA revealed that the decomposition of the composite took place at a slightly higher temperature than that of neat PP. Nanocomposites using EA or DA6 modified MMT showed a decrease in viscosity whereas those using DA12 showed an increase in viscosity. Nanocomposites using the DA12 modified MMT showed the most substantial improvement in terms of both mechanical properties and clay exfoliation. It appears that the longer the amine chain the higher the separation of the clay platelets and the higher the interactions between the clay and the polymer matrix.

Gate location of injection molding is vital to achieve high quality plastic part. The determination of gate location is an important issue in mold design. A computationally efficient scheme based on flow path is proposed to locate the optimum gate for achieving balanced flow. The range of filling time is employed as objective function. Comparisons were made between the flow path search scheme and the existing adjacent node evaluation scheme, and between the objective function of the range of filling time and the existing standard deviation of filling time. The two examples investigated indicated that the search routine based on the concept of flow path is more efficient computationally and the range of filling time is a better objective function to reflect the uniformity of fill.

In this work, a novel biopolymer-based superabsorbent hydrogel was synthesized through crosslinking graft copolymerization of 2-hydroxyethyl acrylate (HEA) onto kappa-carrageenan, using potassium persulfate (KPS) as a free radical initiator in the presence of methylene bisacrylamide (MBA) as a crosslinker. The chemical structure of the hydrogels was confirmed by FTIR spectroscopy. The morphology of the samples was examined by scanning electron microscopy (SEM). The certain variables of the graft copolymerization (i.e. the monomer, the initiator, the polysaccharide, and the crosslinker concentration) were systematically optimized to achieve a hydrogel with maximum swelling capacity. The swelling ratio in various salt solutions was also investigated in detail. Since this hydrogel exhibited a very high absorptivity in saline, it may be referred to as low salt sensitive superabsorbent. The swelling of superabsorbing hydrogels was also measured in solutions with pH ranging from 1 to 13.

The present investigation was directed towards the synthesis of a copolymer of vinyl acetate, butyl acrylate, 2-ethylhexyl acrylate, methacrylic acid and acrylamide to be exploited as a pressure sensitive adhesive (PSA) in transdermal drug delivery systems. The experimental methodology involved the optimization of reaction conditions for the polymer synthesis. The optimal synthesis conditions of PSA were determined as that polymerization reaction of PSA in ethyl acetate with BPO of 0.5% w/w of reactants at 75 oC throughout the whole process with polymerization reaction time of eight hours. The copolymer was then characterized by FTIR, 1 H-NMR, 13 C-NMR and DSC. The PSA was also evaluated for residual monomer content, viscosity, tack, peel adhesion and drug release behavior. The synthesized PSA’s tack is 21#; peel adhesion is 1.39 N/mm. And the residual monomers content in the copolymer after polymerizing for eight hours are VAc 2.98%, BA 0.004%. The PSA also exhibited excellent drug release behavior. Membranes containing oxybutynin were capable of releasing in zero order fashion. It was found that the release velocity depended on the concentration of modified monomer. Drug release from those membranes could be easily tailored by changing the content of the modified monomers. It was found suitable for use in transdermals and could be further exploited either as an adhesive or as a system component in the area of transdermal drug delivery.

A novel, practicable and convenient route has been developed to prepare polymer nanospheres embedded with CdS nanoparticles which show an extremely high photocatalytic activity compared with other photocatalysts. In this method, polymer nanospheres were fabricated through the polymerization of cadmium dimethacrylate which was introduced into self-assembly system of chitosan and 3-mercaptopropionic acid. Then CdS nanoparticles were prepared insitu by inflating H 2 S into the polymer nanospheres.

An artificial neural network (ANN) model was successfully developed for the modelling and prediction of the polarity parameter π used in the revised patterns scheme for the prediction of monomers reactivity ratios in radical polymerizations. Four quantum chemical descriptors based on density functional theory (DFT) calculations were used to develop the ANN model. The optimal condition of the neural network was obtained by adjusting various parameters by trial-and-error. Simulated with the final optimum BP neural network 4-4-1, the results show that the predicted parameter π values are in good agreement with the experimental ones, with the root mean square ( rms ) errors being 0.053 ( R =0.960) for the training set and 0.070 ( R =0.942) for the test set. The ANN model has better statistic quality than the MLR model, which indicates there are nonlinear relationships between these quantum chemical descriptors and the parameter π .

Nanocomposites based on natural rubber and polybutadiene rubber blend were prepared by employing different amounts of modified layered silicate. X-ray diffraction was used to determine the structure of prepared nanocomposites. The effects of incorporation of organically modified clays on vulcanization reactions of the rubber blend were analyzed by using oscillating disk rheometer. High reduction in scorch time and optimum cure time was observed when organoclay was added and this was attributed to the amine groups of the organic modifier. Tensile strength, modulus, abrasion resistance and tear strength improved significantly on adding organoclay and there was a good correlation between abrasion resistance and tear strength of the nanocomposites. Elongation at break decreased by using organoclay and increase in loading of organoclay up to 10 phr and further led to decrease in the rate of variation of tensile properties. Thermal stability of the blend was improved by using 5 phr organoclay.

Blend nanofibers from Chitosan (Cs) (M w =1 X 10 6 ) in 2% acetic acid and poly(vinyl alcohol) (PVA) (M w =72 X 10 3 ) in deionized water were produced in 10/90, 20/80, 25/75, 50/50 mass ratio of Cs/PVA. The effect of blend ratio on the fiber formation and fiber properties has been investigated. Nanofibers produced were characterized by SEM, FTIR and DSC. The diameter of fibers increased with increasing chitosan content in blends. However, fibers with lower diameter showed micro cracks on the surface. FTIR data show that these two polymers have intermolecular interaction. DSC data reveals that the exothermic peak at about 200 0 C for PVA decreased to lower temperature with increasing Cs content. Chitosan (Cs) (M w =1 X 10 6 ) was hydrolyzed and the molecular weight reduced to 6.219 X 105 then we could electrospin the pure chitosan in 90% acetic acid as solvent and the nanofibers with diameter in the range of 43 nm were produced. SEM results showed that although the chitosan nanofibers were produced, because of high viscosity of solution there are a lot of beads on their surface. The cell culture result show excellent cell viability in this medium when the cells were exposed to chitosan/PVA nanofibers for 7 days in CO 2 incubator, 99% RH and 37 °C. On the other hand the chitosan/PVA nanofibers in their antimicrobial experimentations showed efficient antimicrobial properties.

In previous work crosslinked copolymers were prepared from cinnamoyloxy ethyl methacrylate (CEMA) and several monomers feed ratios of octadecyl acrylate (ODA). Networks so produced are both flexible and porous; we now report their swelling efficacies as a function of temperature in toluene and in crude petroleum. Network characteristics is presented including the polymer + solvent interaction parameter χ, effective crosslink density υ e , equilibrium modulus of elasticity E, average molecular weight between crosslinks M c and the theoretical crosslink density υ t . These parameters are correlated with structures of the synthesized sorbers.

In this study, the polyetherblock amide (PEBAX)® nanocomposites with 2.5 % and 5 wt.% organoclay, based on Cloisite 30B (montmorillonite intercalated with dimethyl, 2-ethyl hexyl hydrogenated tallow alkyl ammonium cation), were prepared by the melt-intercalation process. The structural properties, thermal behaviors and the mechanical properties were characterized using the X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), melt flow index (MFI), differential scanning calorimetry (DSC), thermogravimetry analyses (TGA), transition electron microscopy (TEM), scanning electron microscopy (SEM) and the tensile test. The XRD analysis indicated the formation of intercalated PEBAX nanocomposites. The TGA results revealed that the addition of 2.5 wt.% nanoclay improved the thermal properties, while the nanocomposite with 5 wt.% nanoclay did not enhance the thermal stability. The DSC analysis indicated that, in the case of PEBAX with 2.5 wt.% organoclay, each peak was related to the fusion of the crystalline fraction of the poly ether and poly amide affected blocks. On the contrary, regarding the PEBAX with 5 wt.% nanoclay, only the peak related to polyamide was changed. Interestingly, the tensile modulus increased with the incorporation of 2.5 wt.% clay, but it decreased in PEBA 5. The elongation at break reduced with the incorporation of the clay, attaining a minimum value at the clay concentration of 2.5 wt.%, and followed by an increase at the clay concentration of 5 wt.%.

Streaming Induced Potential (SIP) of polystyrene sulfonate, PSS, and poly(ethylenimine), PEI, in the presence of monovalent (NaCl) and divalent (CaCl 2 ) electrolytes, were measured at ambient temperature. The data indicate that screening of polyelectrolyte surface charge, i.e. the reduction of SIP amplitude, is more efficient by divalent CaCl 2 , as compared to monovalent NaCl electrolytes. The screening of polyelectrolyte surface charge leads to reduction of the mutual repulsion between the polyelectrolyte segments. In the case of CaCl 2 electrolyte, since PSS and PEI are, respectively, negatively and positively charged, sequestration of calcium ions by the polyelectrolyte leads to strong reduction of the free calcium ions concentration in the medium in the presence of the PSS when compared to the PEI. Further, the preparation of CaCO 3 particles through a precipitation reaction, at room temperature, by using PSS and PEI polyelectrolytes as crystal modifiers were investigated. The final CaCO 3 particles are found to result from the aggregation of nanocrystals, and have various shapes and sizes depending on polymer concentration and structure. It comes out that the properties of CaCO 3 particles prepared in the presence of the polymer are function of the interaction efficiency between the polymer-repeating units and the calcium ions. Such interaction is found to affect the free calcium ions concentration in the medium.

Changes in conductivity of 5 w/w% starch gels was studied on their titration with 0.1 M aqueous solutions of selected metal salts. Starch gels usually trapped around 10 mg metal ions per 1 g starch [Co(II), Cu(II), Fe(III), Ni(II)] and that value was only slightly dependent on starch origin (amaranthus, corn, potato, tapioca, waxy corn). Among salts studied (acetates, chlorides, nitrates) FeCl 3 and NiCl 2 were likely to be used because they hydrolyzed increasing conductivity of the solutions and formed micelles of corresponding hydroxides adhering to starch micelles and increasing amount of trapped metal. Addition of metal salts to starch gels had a devastating effect on pseudoplasticity and viscosity of starch gels and only potato starch gel was to a certain extent, exceptional in that respect.

This study correlates toughness of polyamide nanocomposites with the molecular mobility of polymer segments in the amorphous phase. Two nanocomposite systems prepared by melt-compounding of polyamide-6 with sodium montmorillonite or organophilized montmorillonite were compared. They differed in the extent of silicate dispersion. While sodium montmorillonite formed intercalated nanocomposites, the organophilization promoted full exfoliation of the silicate layers in the matrix. The different morphology was imprinted in fracture behaviour, toughness of exfoliated nanocomposites was markedly lower that that of their intercalated counterparts. To explain this difference, a solid-state NMR was used as a selective tool for providing information about nanocomposites structure and, primarily, about dynamics of polymer segments. Comparison of NMR spinrelaxation behavior with fracture mechanics experiments revealed a close correlation between fracture toughness and the intensity of rapidly relaxing component of the amorphous phase.

This manuscript describes the elaboration of temperature sensitive highly magnetic latex particles. The particle core is crosslinked polymer matrix containing iron oxide nanoparticles. The shell is a combination of highly crosslinked hydrophobic polymer and crosslinked stimuli responsive hydrophilic polymer. The polymerization was performed in two steps: the elaboration of seed magnetic latex particles for oil in water magnetic emulsion and (ii) the functionalization of the obtained magnetic latexes via seed polymerization in the presence of water soluble reactants. The obtained final core-shell latexes exhibit the following properties: The iron oxide content is above 50 wt.%. The size distribution is governed by the size distribution of the used oil in water magnetic emulsion. The thermal sensitivity of the shell is due to the presence of poly(N-isopropylacrylamide). The cationic character of the outer layer shell is due to the use of cationic initiator and amino containing monomer.

The use of dynamic viscosity/time (temperature) cure curves is seen as a powerful technique to quantify formulation and resin design parameters. The behaviour of different thermoset powder coating systems, epoxy/polyester (50/50, 40/60 and 30/70) as well as the impact of the filler, the curing temperature and the frequency upon gel-time have been examined based upon the rheological measurements and compared with PE/TGIC systems. Two disparate methodologies have been utilized to determine gel-time. The behaviour of dissimilar systems bearing different formulations has been compared by means of the non-isothermal DSC test. The effects of resin percentage and the formulation on physical and mechanical properties of coating have been studied.

Crosslinked hydrogels of poly(acrylic acid) neutralized with calcium hydroxide were synthesized using free radical co-polymerization. The effects of the amount added calcium on the elastic modulus and swelling properties of the gels and the correlation to phase behaviour and structural changes within the gels were studied using texture analysis, gravimetric analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and atomic force microscopy (AFM). It was found that the elastic modulus decreased nonlinearly with increasing amount of added calcium and that the swelling’s dependence on the amount of added calcium was complicated. The maximum swelling increased with increasing amount of added calcium until a critical calcium content was reached, upon which the gels phase separated, with a strong decrease in swelling as a result. The changes in properties are explained by the fact that calcium affects the structure of the polymer network during synthesis and by the phase behaviour of the gels. Changes in the gel structure with the addition of calcium were detected with AFM. Furthermore, AFM revealed different phases on the nanometre scale for the sample with a calcium content around which phase separation is macroscopically observed. Finally, it was shown that the sulphur from the initiator potassium persulfate formed crystal like regions with high sulphur and calcium content upon drying of the hydrogels.

New optically active aromatic poly(amide-imide)s (PAIs) were prepared from newly synthesized N,N΄-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracrboxylic)-bis-Lvaline diacid (4) via polycondensation with various aromatic diamines. The diacid (4) was synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene- 2,3,5,6-tetracarboxylic dianhydride (1) with L-valine (2) in acetic acid. All polymers were obtained in quantitative (high) yields with inherent viscosities of 0.24-0.36 dL/g. All of these polymers were highly organosoluble in solvents like N-methyl-2- pyrrolidone (NMP), dimethylformamide (DMF), N,N'-dimethylacetamide (DMAc) and dimethylsulfoxide (DMSO) at room temperature and were fully characterized by means of NMR spectroscopy, FTIR spectroscopy, elemental analyses, inherent viscosity, solubility test, specific rotation and thermal properties of the poly(amideimide) s were investigated using TGA/DTG.

The effects of polypropylene-grafted-dibutyl maleate (PP- g -DBM) used as compatibilizer on mechanical, rheological and morphological properties of polypropylene (PP) and nylon 6 (PA6) blends was systematically investigated in this paper. The results of Molau test, solvent extraction and differential scanning calorimetry (DSC) indicated the formation of PP- g -PA6 in vicinity of interfaces during melting extrusion. Owing to the reaction between the reactive groups of PPg- DBM and amine (-NH 2 ) end groups of PA6, the tensile and impact strength of the PP- g -DBM compatibilized PP/PA6 blends were much higher than that of the uncompatibilized PP/PA6 blends. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results indicated that the domain sizes of the dispersed phase in the compatibilized PP/PA6 blends decreased and the interfaces become more indistinct, which indicated a clear compatibiliting effect was induced by the PP- g -DBM in the immiscible PP/PA6 blends, i.e. the PP- g -DBM was an effective compatibilizer for the PP/PA6 blends. In addition, the rheological measurements showed the PP- g -DBM compatibilized PP/PA6 blends possessed higher pseudo plasticity, melt viscosity and flow activation energy.

Porous polyacrylamide (PAAm) was synthesized using calcium carbonate (CCb) micro-powder and subsequent leaching process. Polymerization was carried out in a solution environment system containing methylenebis acrylamide (MBA) and acrylamide (AAm) as crosslinker and monomer, respectively. CCb micro-powders were introduced to the polymerization solution before adding initiator. Ammonium persulfate/sodium metabisulfite (APS/SMBS) were used as a redox initiator system. HCl solution was used to remove CCb powders. The effect of MBA concentration and CCB amount on the swelling of hydrogels were studied. The porous structure of hydrogels was investigated and verified using scanning electron microscopy (SEM). 2,4-Dichlorophenoxyacetic acid (2,4-D) was loaded into the hydrogels and release of this herbicide was investigated. The effect of MBA concentration and addition of CCb on the content of released herbicide was studied. Also, the study of herbicide release in a solution under various pH revealed the pH-dependency release of 2,4-D herbicide.

Chemical modification of inexpensive commercial polymers, such as styrene, is a safe methodology to obtain new copolymers. The 4-chloromethyl styrene (CMS) was copolymerized with styrene (in various mole ratios) by free radical polymerization method at 70 ºC using α,α-azobis(isobutyronitrile) (AIBN) as an initiator. The azide ion was covalently attached to the obtained copolymers with replacement of all the chlorine atoms in CMS units. The 1,3-dipolar click cycloaddition reaction between azido polymers and dimethyl acetylene dicarboxylate (DMAD) yielded polymers with 1,2,3-triazoles in side chain. The polymers, obtained in quantitative yields, were characterized by FT-IR and 1 H NMR spectroscopy; thermogravimetric analysis (TGA) and GPC studies. The thermogravimetric analysis (TGA) indicated that the thermal stability of copolymers increases with incorporation of 1,2,3-triazole groups in side chains of copolymers.

Since the work of Armand, polymer electrolytes have received great attention and lots of publication can be found in the literature. Each publication has its particular orientation and tries to emphasize only limited points to prove their system as the better one. But to really get some good fruitful material we need to look simultaneously for different aspects of the electrolyte such as good conductivity and mechanical property, understanding of interaction between the salt and other materials present in the system, nature of solid electrolyte/ electrode interface, electrochemical window, working temperature window etc. Hence a brief summary of the variety of polymer electrolytes is given in the paper with their advantages and disadvantages. Paper discusses polymer electrolytes starting from Dry SPE to the latest IL/Zwitterionic electrolytes and the behavior of the some devices using these materials.

A new serious of fluorinated polybenzoxazoles (PBOs) were prepared from 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane together with 2,5- difluoroterephthalic acid (DFTA) and terephthalic acid by the one-pot polycondensation in polyphosphoric acid. The resulting PBOs showed good solubility in many common organic solvents and the thermal stability of PBOs was improved by the introduction of DFTA monomer.

Three types of coaxial polymer/polyaniline (PANi) fibers were prepared by in situ polymerization of aniline on the electrospun poly(methyl methacrylate) (PMMA), polystyrene (PS) and polyacrylonitrile (PAN) fibers, respectively. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) were applied to characterize the morphologies of these core-sheath structures. Under identical polymerization conditions, a thicker layer of PANi was deposited on the hydrophilic PAN fibers than those on the other two hydrophobic polymer core fibers. The results revealed that the nature of the polymer cores could influence the formation of the coaxial fibers, which may provide a deeper insight into the formation of core-sheath nanostructures.

This paper presents the assay on the radiochemical degradation of UHMWPE films containing rosemary. Three concentrations of natural polyphenolic extract were selected: 0, 0.25 and 0.50 % (w/w). FTIR and UV-VIS spectra were recorded and the variation in the characteristic bands was followed. The accumulation of carbonyl and hydroperoxyl structures was attempted for all samples including neat specimen. The contribution of additive to the protection of UHMWPE against oxidative degradation is discussed in relation with polyphenol concentration and irradiation dose. The spectral information is correlated with the results of chemiluminescence investigation. The increase in the additive concentration brings about significant longer induction times that are determined by the slower accumulation of primary intermediates, hydroperoxides. The antioxidant efficiency of rosemary extract is also revealed by the variation in carbonyl and hydroxyl indexes.

The Monte Carlo method was used to investigate the effect of graft length and architecture on the efficiency of compatibilization in A/B/graft copolymer ternary blends. In this study, homopolymer B is always dispersed phase. When the graft length of the copolymer is relatively short, A 20 B n copolymers (A block is the backbone, and B block is the graft) tend to form micelles in the matrix phase, whereas the B 20 A n (B block is the backbone, and A block is the graft) copolymers tend to form micelles in the dispersed phase. We also find that the micelles in the dispersed phase (formed by B 20 A n copolymers) can effectively suppress the coalescence of the dispersed phases, whereas the micelles in matrix phase (formed by A 20 B n copolymers) have no effect on suppressing the coalescence. As a result, when the graft length is relatively short, B 20 A n copolymers can lead to smaller dispersed phases than A 20 B n copolymers. Moreover, when the graft is relatively long, A 20 B n copolymers were found to connect the dispersed phases and form netlike structure, whereas B 20 A n copolymers were found to locate at the phase interface and anchor the dispersed phase and matrix phase. Furthermore, both A 20 B n and B 20 A n copolymers with relatively long graft lengths can well reduce the size of the dispersed phase.

A novel phosphorus-containing unsaturated polyester resin/SiO 2 hybrid nanocomposite was prepared from the in-situ curing of unsaturated polyester resin (UP) and triethoxysilane (DI) which was synthesized from the nucleophilic addition reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and 3- (trieoxysilyl) isocyanate(icteos). The formation of unsaturated polyester resin/SiO 2 hybrid nanocomposite (UP-DI) was confirmed by infrared spectra (FTIR) and scanning electron microscopy (SEM). With the increase of DI contents, the limiting oxygen index (LOI) value of the cured UP-DIs was raised from 19 to 29, suggesting a significant improvement in flame retardance. The improved flame retardance could also be revealed by the variations of weight and morphology of char residues. Thermogravimetric analysis (TGA) both in air and in nitrogen was used to estimate mechanism of thermal degradation and activation energy ( E a ) of different degree of conversion ( α ) was calculated by Ozawa’s method. The UP-DI containing 10%DI (UP-DI10) had higher E a than the pure UP as α >5% because the degradation mechanism was altered by the incorporation of DI.

Organic/inorganic hybrid was successfully prepared by sol-gel technique, which consisted of polyvinyl acetate (PVAc) as organic segment and titanium dioxide (TiO 2 ) as inorganic part. The PVAc/ TiO 2 hybrid nanofibers were fabricated by electrospinning. The structures and properties of the hybrid nanofibers were investigated by transmission electronic microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analyzer (TGA) and tensile testing. SEM observation revealed the fibrous structures of the hybrid nanofibers. AFM and TEM images indicated the surface morphology and inner structures of the hybrid nanofibers. It was found by TGA analysis that the thermal stability of pure PVAc nanofibers was enhanced by the increase of TiO 2 phase. The breaking strength was increased while the breaking elongation was decreased as the TiO 2 content increased.