Band 11, Heft 1

In this work, biocompatible and biodegradable chitosan microcapsules are successfully prepared in abundance and easily via using carboxylfunctionalized polystyrene (PS) particles as core template and the chitosan crosslinked with gultaraldehyde as the shell. Firstly, the monodisperse functionalized PS particles are made by emulsifier-free emulsion polymerization. The structure and morphology of the carboxyl-functionalized PS particles are characterized by FTIR, FESEM and TEM. Secondly, microcapsules are accomplished by fabricating on the basis of chemical cross-linking on the surface of the carboxyl-functionalized PS particles and by removing the core template. The microcapsules are characterized by FESEM and TEM. The results revealed that the latex particles are removed by exposure to solvent and the microcapsules exhibited the hollow structure. This work confirmed that the microcapsules are accomplished by fabricating on the basis of chemical cross-linking on the surface of the carboxyl-functionalized PS particles and by removing the core template.

The nanocomposites of poly(acryl amide-co-acrylic acid) with NaY and Clinoptilolite were prepared using ammonium persulfate as an initiator and N,N′- methylene bis acryl amide as the cross-linker. The morphology was characterized by SEM and the structure of nanocomposite materials was studied with XRD and FT-IR that showed the interaction between porous materials and poly(AAm-co- AAc). Thermo gravimetric analyzer (TGA) curve shows that all the chain-extended poly(AAm-co-AAc) are stable up to 250 °C and maximum weight loss occurs at 890 °C. The TGA results indicated higher stability for poly(acryl amide-co-acrylic acid)/NaY and Clinoptilolite composites than poly(AAm-co-AAc). The adsorption and desorption behavior of methylene blue were investigated for nanocomposites. It was shown that poly(AAm-co-AAc)/NaY and Clinoptilolite nanocomposites have higher adsorption than NaY, Clinoptilolite and poly(AAm-co-AAc) alone. This effect was attributed to good interaction between the hydroxyl group in porous materials and carboxylic group in poly(AAm-co-AAc) with methylene blue.

Chitosan (CS) based materials in a form of composite with poly(lactic acid) (PLA) granules, films and freeze-dried scaffolds also with blend form with hydroxypropylocellulose (HPC), as well as dibutyrylchitin films were obtained. These structures are intended especially for controlled drug delivery systems, including transdermal and oral dosage forms. Excellent adhesion of biopolymer matrices to PLA microspheres or hydroxyapatite (HAp) particles was proven. The Iorder drug (ibuprofen (IBU)) release kinetics from obtained films is stated.

This paper presents the synthesis and characterization of two oligomers based on monosaccharides (D-glucose and D-mannose). The oligomers were obtained by the polycondensation of two diacids derived from monosaccharides (3- O-benzyl-5,6-(bis(maleyloxy))-1,2-O-isopropylideneglucofuranose and 1-O-benzyl- 5,6-(bis(maleyloxy))-2,3-O-isopropylidenemannofuranose, respectively), with propane-1,3-diol in the presence of p-toluenesulfonic acid. The oligomers were characterized using FTIR and NMR spectroscopy, HPLC-MS and DSC. The copolymerization of the oligomers with 2-hydroxy-propyl acrylate was studied by DSC to evaluate the possibility of obtaining cross-linked copolymers.

Polydimethylsiloxane (PDMS) membranes with different silica content were prepared without support. The characterization and performance of the membranes were investigated by scanning electron microscope (SEM), thermogravimetry analysis (TGA), contact angle meter and swelling experiment. The pervaporation process was investigated with acetic acid/water mixture. And the process of mass transfer was analysed depending on the solution-diffusion model. The addition of silica could greatly improve the pervaporation flux and enhance the thermal stability of membrane. With an increase in feed temperature, selectivity decreased and permeation flux increased for the unfilled PDMS membrane. However, the separation factor of silica loading of 10 wt. % membranes, exhibited a maximum at 50 °C, and it was higher than unfilled membrane when feed temperature was above 40 °C. With the enhancement of acetic acid concentration, flux and separation factor increased. And the unfilled membrane and the silica filled membrane were prior permeation membranes for water when the downstream pressure of unfilled membrane and silica filled membrane was over 1000 Pa and 1500 Pa respectively.

An binary catalyst system of a silica supported Schiff-base cobalt complex SalenCo III (OAC)-MCM-41 (Salen = 3-[N,N-bis-2-(3,5-di-tert-butylsalicylidenamino) ethyl] amine) was developed to generate the copolymerization of CO 2 and propylene oxide in presence of (4-dimethylamino)-pyridine (DMAP). The influence of the molar ratio of catalyst components, the operating temperature, reaction time, and CO 2 pressure on the yield as well as the molecular weight of polycarbonate was systematically investigated. The high selectivity of polycarbonate over cyclic carbonate at 40 °C was maintained after a longer reaction time to attain quantitative formation of the alternating copolymer. High molecular weight of 67 000 were achieved at an appropriate combination of all variables.

A commercially available alkyl halide carbon tetrachloride (CCl 4 ) was used as the initiator for activator generated by electron transfer atom transfer radical polymerization (AGET ATRP) of acrylonitrile (AN) in N,N-dimethyl formamide (DMF). Environmentally benign ascorbic acid (VC) was chosen as the reducing agent and copper bromide (CuBr 2 ) as the catalyst precursor together with iminodiacetic acid (IDA) as the ligand. The polymerization proceeded in a controlled manner as evidenced by kinetic of AGET ATRP of AN, a linear increase of number-average molecular weight (Mn) with monomer conversion and low polydispersity index (PDI) throughout the reactions. The monomer (AN) conversion increased with the increase of VC and CCl 4 . The value of PDI increased with the increase in concentration of VC. For an increase of CCl 4 , the value of PDI decreased first and then increased. 1 H-NMR spectrum of PAN further confirmed the “living”/controlled feature of AGET ATRP of AN.

New type of poly(amide-imide)s were prepared based on novel diacid monomer containing softening siloxane groups. Bis(p-aminophenoxy) dimethyl silane (3) was prepared by the reaction of dimethyl dichlorosilane with paminophenol in toluene. N,N'-Bis(4-trimellitimidophenoxy) dimethylsilane (5) as a novel aromatic dicarboxylic acid containing silicone moiety was synthesized by condensation of bis(p-aminophenoxy) dimethylsilane with trimelitic anhydride in acetic acid. The structure of diacid 5 was confirmed using various spectroscopy methods. The direct polycondensation technique was used for the polyamidation of monomer 5 with several aromatic diamines using pyridine / 2-methylpyrrolidone / triphenyl phosphite / CaCl 2 as condensing agent. The resulting novel poly(amideimide- siloxane)s were obtained in high yields and inherent viscosities. These polymers were characterized using FT-IR, 1 H-NMR, thermogravimetric and elemental analysis techniques. The results show that silicone modified poly(amideimide) s show high solubility and excellent thermal stability.

An experimental study of the flow-induced scission behaviour of four star hydrolyzed polyacrylamides (HPMA) with different arms during planar elongational flow in a cross-slot flow cell is described. The results showed that the shear stability of linear HPAM in distilled water was not essentially different from star HPAM. Polymer scission was not observed in either system in a shear rate range from 20,000 to 100,000s -1 , which can be attributed to the strong polyelectrolyte behaviour of HPAM in distilled water. However, at the same shear rate, the star HPAMs exhibited superior shear stability in comparison to the linear HPAMs in aqueous solutions containing NaCl (C NaCl =0.2-1.0%wt) and, in particular, the initial reduction rate of relative viscosity (R) decreased with the degree of branching of the HPAMs. In addition, it was found that the R of five HPAMs in NaCl aqueous solutions exhibited an exponential dependence on shear rate, in which the coefficient C 1 can be used to quantitatively evaluate shear stability. In star HPAM NaCl aqueous solutions, the increase of R with shear rate is very likely due to the decrease of the hydrodynamic radius (R h ) of these HPAMs, while the increase of R with NaCl concentrations can be attributed to the relatively low viscosity of these polymers at high NaCl concentrations.

Shelf life at room temperature and curing behaviour at elevated temperature are studied for hot-curing accelerated epoxies (EP, diglycidylether of bisphenol A plus dicyandiamide (Dicy)) by FTIR-spectroscopy and modulated DSC. The accelerator is added either directly or with nano-zeolite filler to the EP. Due to the immobilisation of the accelerator in the pores of the nano-zeolite, the shelf life of this EP is 5 times longer than for the EP containing free accelerator. While the free accelerator acts during the whole heating step to curing temperature, the nano-zeolite does not release the accelerator before ca. 100 °C. As monitored by light microscopy, the released accelerator not only supports the curing but also stimulates the dissolution of the solid Dicy. As the result, network formation at 170 °C finishes within less than 25 minutes for the nano-filled EP.

Coalescence during annealing of quiescent immiscible polymer blends, containing polypropylene (PP) matrix and different amount of ethylene-propylene copolymer (EPR) as dispersed phase, was studied. Comparison of experimental results with available coalescence theories revealed that changes in the phase structure after 20 min annealing can be precisely estimated using the approximate theory of coalescence induced by van der Waals forces and considering drainage of the matrix film between spherical droplets. All results evidenced growth of the EPR droplet size with the annealing time and temperature; increase in the content of dispersed phase contributed to higher growth rate of the dispersed phase, more pronounced at the coalescence origin. Anisometry of the EPR droplets and droplet shape relaxation were perceived, both interfering the course of coalescence. Enhanced elasticity of examined blends at low frequencies and positive deviation of the complex viscosity from the linear mixing rules was observed.

Photocatalysts have attracted much scientific interest stemming from their high catalytic efficiency and environmental friendly properties. However, due to the development of nanosicence and nanotechnology, nano-photocatalysts have attracted more and more attention. Generally speaking, nano-photocatalyst indicates photocatalytic materials in nano size, including nanoparticles, nanofibers, nanowires, and so on. Electrospinning, used as a simple method to fabricate nanomaterials, is playing a very important role on nano-photocatalyst research, both on the production of novel nano-photocatalysts and on the study of innovative fabrication methods. The applications of electrospinning on nano-photocatalyst research are reviewed with an emphasis on fabrication of nano-photocatalysts and on the strategies that have been tried to improve nano-photocatalysts performance.

The addition of BaSO 4 whose mass fraction was less than 0.052%, could improve the mechanical property and thermal stability of the fibre apparently. It was found that, the smoothness of the hybrid fibre was changed by BaSO 4 appreciably, though allowable in actual production; The BaSO 4 did not obviously affect the crystallization index ( a ) and the relative degree of crystallization. With the content of BaSO 4 increasing, the crystallization rate firstly became smaller slightly and then restored to the original level at the primary crystallization stage, but the crystallization rate revealed a small fluctuation at the secondary crystallization stage. In addition, the Ozawa equation was fit for pure PET well, and the Mo equation was fit for pure and hybrid PET.

A series of Inorganic/organic nanocomposites were prepared by blending cage-like carboxyl-bearing polyhedral oligomeric silsesquioxane (carboxyl-POSS) with polymethyl mathacrylate (PMMA) in THF solvent. FTIR and 29 Si-NMR were employed to characterize the structures of the nanocomposites. SEM images showed that the as-prepared films were smooth and no aggregation of carboxyl-POSS was observed. TGA and DSC results showed that the incorporation of small amount of nanosize carboxyl-POSS enhanced the thermal stability of PMMA. When 1.0 wt% of carboxyl-POSS was incorporated into PMMA matrix, the T g and T d increased by 16.9 °C and 21.0 °C, respectively. However, higher POSS contents (>1.0 wt%) would deteriorate the thermal and mechanical properties of the nanocomposites.

Intelligent temperature-sensitive hydrogels have been synthesized using a hierarchically organized, porous silica gel as template. The organic gels were obtained by three-dimensional copolymerization of N-isopropylacrylamide and N,N’- bis(acryloyl)cystamine in the free volume of a monolith of a porous silica gel. After characterization, the silica matrix was dissolved in alkali. Unexpectedly, the remaining organic polymer showed similar properties to a gel obtained in homogeneous solution. The shape of the inorganic mould was retained in the purely organic hydrogel even after dissolution of the inorganic part and it showed the ability to collapse under enhanced temperatures. The collapse rate of the gel prepared via the template synthesis was much higher compared to gels prepared conventionally.

Novel polypropylene/clay nanocomposites were prepared by in situ polymerization method with TiCl 4 /MgCl 2 /organoclay/internal donor- AlEt 3 catalyst. The organo clay used is commercial Closite 15A that is an ammonium saltmodified montmorillonite (AMMT). For preparation of the catalyst, MgCl2 was deposited into the swollen AMMT layers and then TiCl4 and internal donor were loaded on the layer surfaces of AMMT. X-ray diffraction (XRD), transmission electron microscopy (TEM) and rheological measurements were used for characterization of the nanocomposites. The Linear and nonlinear melt-state viscoelastic properties of the polymer matrix and its nanocomposite are also investigated. In the presence of the clay lamellae, a pronounced increase in the low frequency moduli is observed. Transient rheological data reveal a stress overshoot for nanocomposite where there is no significant overshoot for polymer matrix. This stress overshoot can be attributed to the deformation and orientation of the special structure of clay platelets in polymer melts. Finally, experimental data are compared with the predictions of a mesoscopic rheological model.

A novel electrospinning setup was employed for producing aligned polyacrylonitrile (PAN) monofilament in nanoscale. Unlike conventional method, the PAN monofilaments is collected using a rotating drum with various linear speed from bulk of nanofibers. it originates from two syringe infusion pumps contain 14wt% PAN/DMF solution which passes through two separate high voltage electric field. Various collecting drum speed were examined to clarify its effect on degree of alignment, internal structure and mechanical properties. Image process technique used to illustrate the best degree of alignment for nano-monofilament collected at take up velocity of 59.5 m/min. The amount of Crystallization Index (C.I) and orientation parameter calculated respectively from FTIR spectra and Raman spectra also supports the results demonstrated by image processing techniques. The ultimate strength and elastic modulus of nano-monofilament bundles increase with increase of take up velocity. They approach respectively to a maximum of 73.7 MPa and 4.2 GPa at take up velocity of 59.5 m/min. Results acquired by differential scanning calorimetry (DSC) show no significant effect on glass transition temperature with increasing take up velocity. However, minimum value of evolved heat caused by chemical reaction was obtained at surface speed of 59.5 m/min.

A series of ethylene vinyl acetate random copolymer EVA, with vinyl acetate (VA) varied from 9 to 91m%, was investigated by differential scanning calorimetry DSC and polarized optical microscopy. Biodegradable polymer blends of polyhydroxybutyrate PHB and EVA, having VA in EVA in range from 40m% till 91m%, were prepared by film casting from a chloroform solution. The miscibility and crystallization behavior of these blends were investigated. The isothermal crystallization behaviors of PHB and PHB/EVA blends are discussed in terms of the half time of crystallization t 1/2 . Experimental results indicated that blends of PHB/ EVA91 are completely miscible blend in the entire (0 to 100 m%) compositional ranges. Blends PHB/ EVA, for VA varied from 40 till 70 m% are immiscible as evidenced by the existence of unchanged composition independent glass transition temperatures (T g ), crystallization and melting behavior. The isothermal crystallization of PHB blends was investigated from room temperature till 130 °C. 80 °C was found to be the best temperature for comparison of different blends. At 80 °C t 1/2 strongly depends on the content of VA in PHB/EVA blend, mainly due to differences in miscibility as well as due to differences in segmental mobility as identified by differences in glass transition temperature. Since both components in PHB/EVA80, pure PHB and pure EVA80, have glass transition temperatures close to 0 °C, it is difficult to decide its miscibility from T g . However from the strong dependence of the value of crystallization half time t 1/2 of PHB/EVA80 on blend composition, it was possible to reasonably infer that PHB/EVA80 is partially miscible.

Exfoliated and toughened polypropylene nanocomposites prepared by an introduction of a rubber in the form of compatibilizer toughener: ethylene propylene diene based rubber grafted with maleic anhydride (EPDM-g-MAH) were studied in terms of weld line properties and morphology. Effects of addition of rubber and nanolayer on weld line strength under tensile loading condition of polypropylene matrix were investigated. Data showed that in the absence of either EPDM or nanolayers, a sharp decrease in weld line strength cannot be avoided whereas in the presence of each in optimum ratio, the drastic increase in both toughness and weld line strength values can be easily reached. The beneficial effect is believed to come from the selective placing of nanolayers around the rubber droplets and making them smaller in size which contributes to diffused weld line regions with high mechanical strength.

The Halpin-Tsai equations were used for the composites with low level content of reinforcements, which contain lamellar shape, high modulus and high aspect ratio. These characteristics of reinforcements were taken into consideration to simplify the Halpin-Tsai equations. The effect of different parameters on the longitudinal Young’s modulus of well aligned polymer/clay nanocomposites was investigated for both exfoliated and intercalated microstructures. It was shown that the applied simplification had negligible effect on the prediction of the Halpin-Tsai model. For the intercalated structures with a high number of platelets per stack (n), increase in the gallery spacing did not influence the predicted modulus values. In an intercalated structure, the surface area of a stack, as the interface of fillermatrix, is n times lower than that of the exfoliated state. By considering the effect of the degree of exfoliation in the proposed model, a new equation was developed to predict the modulus enhancement in the nanocomposites filled with Montmorillonite (MMT). The theoretical predictions were supported by the experimental results.

New method of synthesis of polyetherols with 1,3-pyrimidine ring by reactions of 6-aminouracil with ethylene carbonate and propylene oxide was described. The structure of products was analyzed using the IR, 1H-NMR and MALDI-TOF spectroscopies. Some physical properties and thermal stability of polyetherols were investigated. Initial tests on the foaming of polyurethanes obtained from the polyetherols were performed. Some properties of the foams such as apparent density, absorption of water, linear dimensions stability, thermal resistance and compression strength were investigated. Obtained foams show an improved thermal stability.

Composites from some novel polyimide and commercial epoxy were prepared aiming to improve the thermal behavior of epoxy resins. Two diamines namely 4-4'-diamino-4''-hydroxytriphenyl methane (DHTM) and 4-4'- diaminotriphenyl methane (DTM) were synthesized by reacting aniline and aldehydes according to a reported method. The synthesized diamines were blended with commercially available epoxy 1, 4-butanedioldiglycidylether (BDDE) to synthesize model epoxy amine networks which were compared with polyimideepoxy composites. The polyimides were synthesized by reaction of these diamines with aromatic anhydride namely 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA). These synthesized polyimides were dispersed in epoxy diamine networks to prepare composites. All the monomers and composites were characterized by making use of various analytical techniques including FTIR, NMR, TGA, DSC and XRD. Presence of hydroxyl group in the diamine helped in better dispersion of polyimide leading to high T g and high char yield at 600 °C.

The flow induced crystallization behaviour of a LDPE:PE-g-MA:D72T 90:9:1 nanocomposite has been investigated by in-situ Rheo-SALS technique and data have been compared with those obtained from a reference LDPE:PE-g-MA 90:9 sample. Rheo SALS results, confirming thermal analysis findings, indicate that under mild shear flow fields the organoclay exhibits a negligible nucleating effect. Both nucleation density and, as a consequence, crystallization rate, are not appreciably affected by the application of external flow field for both the examined systems, revealing that no evident synergic effects between the organoclay and the shear flow are present. On the other hand, Rheo SALS analysis indicates that the nanocomposite submitted to flow exhibits a higher level of crystal orientation. TEM morphological analyses support this observation suggesting that the orientation of the nanofiller along the flow direction templates the growth of oriented crystals.

Two terpolymers of styrene, divinylbenzene, and 1-vinylimidazole (S/DVB/VI) or N-vinylpyrrolidinone (S/DVB/NVP) were prepared by radical polymerization. Palladium nanoparticle catalyst has been “heterogenized” by anchoring to these polymers the [PdCl 2 (PhCN) 2 ] complex via ligand exchange reaction. The formation of coordination bond between S/DVB/VI, S/DVB/NVP terpolymers and Pd 2+ ions was studied using infrared and XPS. Immobilized palladium complex was reduced during hydrogenation reaction or by reaction with sodium borohydride. Characterization of polymer supports and palladium catalysts has involved the measurements of the structural parameters in the dry state by the nitrogen BET adsorption, X-ray photoelectron spectroscopy (XPS), AAS spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Both the catalytic systems were found efficient in the hydrogenation of cinnamaldehyde. The stability and a good recycling efficiency of these catalysts make them useful for prolonged use. The factors influencing selectivity of supported catalysts were discussed. The results offer the possibility of using these terpolymers for the immobilization of metal complex catalysts for hydrogenation and other catalytic reactions.

Dependencies of physical-chemical characteristics on structure development during polymerization of organic-inorganic systems (OISs) have been investigated. The non-monotonic behavior of the physical parameters has been found. This effect was explained by complicated structure of OISs, which consists of two interpenetrating hybrid organic-inorganic networks, which are characterized by different rate of the structure formation.

Phase transition behavior of silicone based liquid crystalline (LC) polymers with variable isotropic transition temperatures (T i ), synthesized from poly(methyl hydrosiloxane), 10-undecenoic acid based crosslinking agent and cholesterol based side chain mesogen, was studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD) measurements. The chemical structure of the mesogenic monomer and the LC polymers were confirmed by Fourier transform infra-red (FT-IR) spectroscopy and 1 HNMR spectroscopy. DSC studies showed that the glass transition temperatures (T g ) and T i of the LC polymers decreased with increasing proportion of mesogenic crosslinking agent at its low proportion and at its higher proportion Ti disappeared completely indicating that the polymeric chains had less chance to orient in the network structure. The results were consistent with the XRD and POM studies.

Poly(dimethyl-methyltrifluoropropyl-methylvinyl)siloxanes (PFMVS) with various contents of trifluoropropyl groups were prepared by ring-opening copolymerization of 2,4,6-trimethyl-2,4,6-tris(3,3,3-trifluoropropyl) cyclotrisiloxane (D 3 F ), octamethylcyclotetrasiloxane (D 4 ) and 1,3,5,7-tetramethyl tetravinylcyclotetrasiloxane (D 4 Vi ). All the polymers were characterized by IR, 1 HNMR, 29 SiNMR, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) measurements. The results show that methyltrifluoropropyl-siloxane units in the copolymer can disrupt the molecular regularity and lead to noncrystalline copolymers with low glasstransition temperatures. Moreover, the onset temperatures of thermal degradation and the glass transition temperatures of polymers decrease gradually with the content of trifluoropropyl groups increasing. Then the thermal stability and solvent resistance of elastomers based on PFMVSs were measured. The data of TGA indicate that the thermal stability of fluorosilicone elastomers are less than conventional methyl vinyl silicone rubber (MVQ), but the fluorosilicone elastomers have outstanding solvent resistance. The content of the trifluoropropyl groups influences the performances of elastomer to a certain degree.

We first report a novel route to synthesize centimeter-scaled polypyrrole (PPy) fiber in the presence of oligo-polyacrylamide. The Fourier transform infrared and ultraviolet-visible spectra reveal that the fiber is in high conductive state. The PPy fibers have a uniform diameter of 300 μm, and length varying from several millimeters to 4 cm. The temperature dependence of electrical conductivity reveal that the transport properties of PPy fibers should be dominantly characterized by phonon-assisted hopping mechanism. Polymer-directed crystal growth may provide promising routes to rational synthesis of various ordered organic materials with complex form and structural specialization.

The sol-gel base catalysed hydrolytic polycondensations of tetramethoxysilane (TMOS) were studied in the presence of quaternary ammonium chloride substituted polyhedral oligosilsesquioxanes (POSSes): octa{3-[(2- hydroxyethyl)dimethylammonio]propyl chloride}octasilsesquioxane or octa[3-(noctyldimethylammonio) propyl chloride]octasilsesquioxane. Small amounts of these POSSes added to the sol-gel system markedly affected the morphology of the silica gel polycondensation products. The morphology was highly dependent on the POSS concentration. Amorphous mesoporous silica gels were obtained showing a high porosity and the surface area up to 615 m 2 g -1 . Most of gels had a fairly large average pore diameters, 4-11 nm and pore volume 0.4-1.3 cm 3 g -1 . TMOS having inserted hexamethyltrisiloxane chain, 1,1,1,7-tetramethoxyhexamethyltetra siloxane, (TMOSD 3 ) in the mixture with TMOS was also used as the monomer in the sol-gel polycondensation; but obtained gels showed a low porosity.

The hydrogels of crosslinked chitosan with different glutaraldehyde amounts have been “in vitro” tested as carriers for prolonged release of some drugs for inflammatory and bronchopulomonary diseases. These hydrogels have been loaded with two novel nitric oxide donors, derivatives of 7-[2-nitroxyacethyloxy- 3-(4-acethyl-amino-phenoxy)-propyl]-8-R-1,3-dimethyl-xanthine compounds (R=H, NO 2 for 65 and respectively 77 compounds) designed as multitarget drugs and parent compounds as paracetamol, theophylline, two xanthine derivatives 7-[2- hydroxy-3-(4-acethyl-amino-phenoxy)-propyl]-8-R-1,3-dimethyl-xanthine derivatives with (R=H, NO 2 for D 1 and respectively D 2 ) and their release was evaluated in an acidic solution (pH=2.2) simulating the gastric fluid. Results have been correlated with the swelling behaviour which was also followed in acidic media with pH=2.2. The relationships between the release profiles and kinetics and matrix characteristics and/or drug properties have been established.

Two novel polyazines were successfully synthesized via palladiumcatalyzed Suzuki coupling method of N,N'-bis(5-bromothiophene)-2-aldehyd azine with 2,5-thiophenediboronic acid and 9,9-dioctylfluorene-2,7-diboronic acid, respectively. The polymers were characterized by 1 H-NMR, FT-IR and UV-VIS spectroscopy. The thermal properties of the polymers were investigated by TGA analysis. The semi-crystalline structure of these compounds was demonstrated by X-ray diffraction study.

Carbon black-filled polymer composites were investigated as sensing materials for organic liquids. Polypropylene and polystyrene which were selected as matrices and various amounts of carbon black were considered as the main factors influencing sensitivity of the composites in view of the percolation theory. Disposable filaments were produced of these materials. Change in their electrical resistivity was measured upon immersion in benzene, toluene, xylene, ethylbenzene and their mixtures. It has been found that studied materials were sensitive to the composition of liquid mixtures of organic solvent. Relationships between the filament response and volumetric fraction of the components were presented. The studied materials have shown promising sensing properties, which suggest their applicability for identification and quantification of multicomponent organic liquids.

Polystyrene latex particles were prepared by using an emulsifier-free emulsion polymerization with two ionic initiators: potassium persulfate (KPS) and 2,2’-azobis(2-amidinopropane)dihydrochloride (AIBA). The purpose of this study was to obtain polystyrene latex with a good stability in time, a high surface charge density and a small particle size (between 100 and 1000 nm). We used two distinctive molar concentrations for both initiators: 5.5 mM and 55 mM based on aqueous phase. The analysis showed that in the case of KPS initiator the latexes stability was better. With AIBA as initiator smaller latex particles can be achieved. A high surface charge density was measured for large initiator concentration. We achieved satisfying results with both initiators, the optimal condition of polymerization depending on the subsequent utilization of the latex. The SEM images showed that latexes containing bentonite and latexes with no clay have similar size.

Magnetic field effect on the elasticity was investigated for magnetic carrageenan gel when a shear and compressional deformation was applied to the gel. The magnetic carrageenan gel consists of carrageenan of a polysaccharide, and carbonyl iron particles. The dynamic viscoelastic measurement with shear strain revealed that the storage shear modulus of the gel increased from 1.0×10 4 to 2.3×10 6 Pa by applying a magnetic field of 320 mT. On the other hand, the compression measurement showed that the Young’s modulus increased from 6.2×10 4 to 5.9×10 5 Pa. The relative changes in the modulus with respect to the original modulus were 230 for shear strain and 9.5 for compressional strain, respectively. This strongly indicates that the magnetic field effect on viscoelasticity strongly depends on the geometry of directions of magnetic field and strain. The effect of vibration suppression of the present gel tuned by magnetic field is also presented.

Several novel ether or thioether linkage containing aliphatic polyesters and poly(alkylene dicarboxylate)s for comparison were synthesized and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermogravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the ether or thioether linkage-containing polyesters. The decrement of the thermal stability appears to be more relevant in the case of presence of sulphur atoms. At room temperature the samples appeared semicrystalline, except PTTDG and PDEDG, which were viscous oils; the effect of the introduction of ether or thioether group was an increment of the T g value, a decrement of the melting temperature and a significant decrease of the crystallization rate. The entity of the variations was found to be affected by the kind of group introduced, and the trend observed can be explained on the basis of atom electronegativity and dimensions.

The coagulation process of nascent fiber of cellulose with ionic liquid 1- allyl-3-methylimidazolium chloride (AMIMCI) as the solvent was studied during drywet spinning. The diffusion rate and the crystallization situation of nascent fiber were tested, its fracture morphology was observed, and the diffusion coefficient D of solvent and the crystallization degree of nascent fiber were calculated according to relevant equations. The diffusion rate and diffusion coefficient of ionic liquid decrease with cellulose concentration increasing in spinning solution and then remain almost the same when the cellulose mass fraction reaches 7%. With the increase of coagulation bath concentration, the diffusion rate and diffusion coefficient of the solvents increase first and then decrease. When the coagulation bath concentration reaches 5%, the diffusion rate and diffusion coefficient of the solvents are at their maximum. With the increase of coagulation bath temperature and the length of air gap, the diffusion rate and diffusion coefficient of ionic liquid increase slightly. The cellulose solution concentration and the spinning air gap have an influence on the crystallization degree of nascent fiber. With the increase of cellulose solution concentration and the spinning air gap, the crystallization degree of the produced nascent fiber increases slightly, but the coagulation bath temperature basically have no influence on the nascent fiber formation.

Electrically conducting nitrile rubber (NBR) containing electro-conductive carbon black (CB) and polypyrrole as conducting-modifier were prepared by single-step in situ polymerization with mechanical mixing and compression molding (vulcanized). Our result showed CB/NBR and CB/ polypyrrole /NBR conducting composites presents high thermal stability. Thermo-gravimetric analysis showed that the CB 50 phr / polypyrrole 10 phr /NBR of composites formula has highest thermal stability with improved degradation temperature from 422 °C (NBR matrix) to 440 °C at 10% weight loss. CB 50 phr and polypyrrole 10 phr has still optimum volume resistivity values 2.83×10 10 to 2.03×10 3 ohm-cm above the percolation threshold. Therefore, incorporating CB with polypyrrole conducting-modifier showed four causes of advantage i.e. increase in thermal stability, conductive pathways, synergistic properties on thermal stability with reinforcement mechanical properties and compounding conductivity effect within the rubber matrix.

The mechanism of conductivity enhancement in PEDOT/PSS film doped with sorbitol is investigated by X-ray diffraction (XRD), Fourier transform Raman spectroscopy (FT-RM), Atomic force microscopy (AFM), Scanning electron microscopy (SEM). The XRD show that the amorphous state of sorbitol-doped films is not changed and the FT-RM indicate that the main characteristic absorption peak of PEDOT shifts to red. These observations indicate that the increase in conductivity is not attributed to the crystallization behavior of PEDOT, but to the change of the resonant structure of PEDOT chain from a ‘benzoid’ to a ‘quinoid’ structure, which increase the rigidity of PEDOT chain. In addition, there is a conformational conversion of the PEDOT chains from the coil structure to expanded-coil or linear structure. These chains changes are helpful to charge transport through the PEDOT chains and conductivity enhancement of composite films. The increased inter-molecule interactions were investigated by the morphological changes of films as observed in AFM and SEM images, which further confirmed the change of the resonant structure of PEDOT chain.

The block copolymer of polystyrene-block-polyacrylate-blockpolystyrene (PSt-PAA-PSt) has been synthesized by reversible addition fragmentation chain-transfer (RAFT) polymerization using S,S′-Bis(α,α′-dimethyl-α′′-acetic acid)-trithiocarbonate (BDATC) as chain transfer agent. Three copolymers form micelles in an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]). The nanostructures of the PSt-PAA-PSt micelles formed in ionic liquid were observed by transmission electron microscopy (TEM). The self-assembled morphologies of the micelles are strongly dependent on the length of PAA block chains when the chain length of PS is fixed. The affinity of PAA chains for water and [BMIM][PF6] reverses with increasing temperature. Research results show that the copolymer with low polydispersity can be obtained by controlling polymerization, and the flexibility of amphiphilic block copolymers for controlling nanostructure in an ionic liquid presents potential applications in many arenas.

Anion activated adiabatic polymerization of ε-caprolactam was investigated in the presence of various quantities of nano-SiO 2 . The parallel processes of crystallization and polymerization are separated first. Based on the crystallization kinetics and electron microscopic investigations it was shown that nano-SiO 2 particles are heterogeneous nuclei for the crystallization of poly-ε-caprolactam. Further the time dependence of mean length of amorphous polymer macromolecules is determined experimentally.

Bisupported catalyst for ethylene polymerization was prepared by mixing alcohol solution of MgCl 2 with pretreated SiO 2 in heptane, the prepared bisupport was modified by treatment with alkyl aluminum compounds, and further treatment with bis(4-(4-amine-3,5-diisopropylbenzyl)-2,6-diisopropylphenylimino) acenaphthene NiBr 2 (abbreviaed as NiLBr 2 ) solution. The most significant feature of the supported catalyst is that it polymerizes ethylene with high activities in the presence of inexpensive general alkylaluminum compounds. According to the results of high temperature GPC, the number-average molecular weights of the polymers ranged from 2.15×10 5 to 9.27×10 5 and the polydispersities ranged from 3.12 to 4.23. By modulating the polymerization temperatures, the products of different and good morphologies were obtained. The resultant PE was confirmed by 13 C NMR to contain significant amounts of not only methyl but also ethyl, propyl, butyl,amyl, and long branches (longer than six carbons).

Surface properties of silicone hydrogels used as soft contact lenses play an important role in biocompatibility, conformability and deposition of protein. In this report, the surface hydrophilicity and protein deposition resistance of silicone hydrogel were modified using an atmospheric pressure glow discharge plasma (APGDP) induced graft polymerization of 2-methacryloyloxyethyl phosphoryl choline (MPC). Silicone hydrogel was treated with plasma and exposed to air to form oxide and hydroperoxides at the surface, which initiated surface graft polymerization of MPC. Elemental composition and structure at the surface of silicone hydrogel were characterized through ATR-FTIR and XPS. The data of ATR-FTIR and XPS analyses revealed that MPC was grafted onto the surface of silicone hydrogel. Contact angle measurement was used to evaluate the hydrophilic property of the silicone hydrogel. The MPC grafted silicone hydrogel has the contact angle about 55° when MPC solution with the concentration 10 wt% is applied for graft polymerization. The result showed that graft polymerzation of MPC improved the hydrophilicity of silicone hydrogel efficiently. Bovine serum albumin (BSA) was used as a model to investigate protein deposition resistance of the modified silicone hydrogel. The data obtained by bicinchoninic acid assay revealed that the grafted silicone hydrogels had a significant enhancement of protein resistance.

Synthetic hydrogels are often used in biomedical applications as many of them are compatible with living tissue and moreover they can meet most criteria for artificial tissue properties. For applications in tissue engineering modification of polymer surface using some bioactive compounds (e.g. saccharides, proteins) for promoting the process of cell adhesion and proliferation is widely used. In this work, a series of modified hydrogels was prepared by three different methods: by copolymerization of 2-hydroxyethyl methacrylate with methacrylic acid, by hydrolysis and oxidation of poly(2-hydroxyethyl methacrylate) to obtain carboxyl-rich supports. The influence of the reaction conditions of the hydrogel surface treatment on the total carboxylic group content and the swelling degree was studied. The modified hydrogels were characterized by attenuated total reflectance FT-IR spectroscopy and refractive index measurements. Obtained carboxylic groups on the hydrogel surface have allowed the immobilization of avidin in two ways: 1) electrostatically through dissociated carboxylic groups and 2) covalently bonded through activated carboxylic groups by Nhydroxysuccinimide. The capacity of hydrogels for avidin immobilization was determined by Bradford spectrophotometric method. The results so far obtained from the preliminary biological tests showed that immobilized avidin on the hydrogel surface provides better adhesion and proliferation of keratinocytes compared to supports without avidin.

A New type of sulfone (4) containing 1,1´-thiobis(2- hydroxynaphthalene) diacid as a monomer was synthesized from the reaction of 2-hydroxynaphthalene (1) and sulfur dichloride, followed by reaction with methylchloroactate to obtain diester (2). Oxidation of this product in the presence of hydrogen peroxide followed by basic hydrolysis led to corresponding sulfone diacid (4) in good yield. Six organic-soluble poly(ether-amide)s bearing sulfone groups were synthesized via direct polycondensation of diacid (4) with commercially available aromatic diamines in the presence of calcium chloride as dehydrating agent. The resulting polyamides had inherent viscosity ranging from 0.38 to 0.46 dLg -1 at concentration of 0.5 gdL -1 in N,N-dimethylacetamide at 30 °C. The glass transition temperatures of these polyamides were recorded between 276-327 °C in air atmosphere. These polymers were also characterized by IR, 1 H NMR and elemental analysis and their physical properties including viscosity, solubility properties, thermal stability and thermal behaviour were studied. These polyamides showed very good thermal stability and solubility in polar aprotic solvents.

Solid-state polymerization has been widely used to prepare high molecular weight poly(ethylene terephthalate). Solid-state polymerization is generally carried out by heating solid, melt-phase-polymerized polymer below its melting temperature but above its glass transition temperature. Solid-state polymerization of poly(trimethylene terephthalate)(PTT) is not an independent process but rather an additional process with respect to melt polymerization that is used when PTT of a higher molecular weight is required. Two kinds of commercial PTT chips were polymerized in the solid state to prepare high molecular weight PTT, which were characterized by end group contents, molecular weight, thermal analysis and X-ray diffraction. In the solid-state polymerization of PTT, the overall reaction rate was governed by the reaction temperature, reaction time and pellet size. The content of carboxyl end groups was decreased during the solid-state polymerization with increasing reaction time and temperature. The melting temperature and crystallinity of solid-state-polymerized PTT were higher at longer times and higher temperatures of polymerization. The activation energy for the solid-state polymerization of PTT was in the range of 24~25 kcal/mol for each chip. Through the solid-state polymerization of commercial PTT chips, we could get high molecular weight polymers up to an intrinsic viscosity value of 1.63 dl/g, which is equivalent to about a 117,000 weight-average molecular weight.

A series of oligomeric alkylpyridinium surfactants were prepared directly in aqueous media by atom transfer radical polymerization (ATRP) of a surfmer, 4- vinyl-N-dodecylpyridinium bromide, and their surface activities were examined in comparison with the surfmer. The resulting oligomers have narrow molecular weight distributions, with polydispersity indices in the range of 1.17-1.23. By using 2-morpholinoethyl 2-bromo-2-methylpropanoate as ATRP initiator, the molecular weight of oligomeric surfactants was characterized by 1 H NMR and the results were close to those obtained from GPC analysis. It was found that critical micelle concentration (CMC) of the oligomeric alkylpyridinium surfactants shifted to lower concentrations with increasing degree of polymerization (DP n ), and their γ-cmc values were smaller by about 4 to 8 mN/m than that of the corresponding surfmer. Among the series of surfactants, the oligomer with highest DP n showed the greatest efficiency in lowering the surface tension in aqueous solution.

A series of novel thermotropic liquid crystalline was synthesized from bi(p-hydroxyl benzoic acid)hydroquinone ester (PHQ), triethylene glycol and 2,4- toluenediisocyanate (2,4-TDI) by altering the molar ratio of PHQ and diol, and PHQ was prepared by using hydroquinone and p-hydroxybenzoic acid as raw materials. The thermotropic mesophase behavior, the melting point temperature (T m ) and the isotropization temperature (Ti) of the synthesized polyurethanes were characterized by FT-IR, DSC and POM. It showed that all of the polyurethane polymers exhibited nematic textures at temperature of 110~230 °C. The shift of the melting and isotropization temperature (T m , T i ) to lower temperature is discussed to be a consequence of the increasing amount of diol content.

A novel nylon 6/11/montmorillonite nanocomposite was prepared by in situ copolymerization of prepolymer of caprolactam with aminoundecanoic acid in the presence of organoclay, and characterized in terms of Fourier transform infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (WAXD), transmission electron micrograph (TEM), intrinsic viscosity as well as differential scanning calorimetry (DSC). It was found that the addition of organoclay had great influence on the intrinsic viscosity and melting behavior but not on the crystal transition of nylon 6/11 matrix. Intercalated/exfoliated and stacked silicates layers were observed for various nanocomposites.

Using a cubic-anvil high pressure apparatus, nylon 6 samples were annealed under 400 MPa to 1.5 GPa. The structure changes of nylon 6 are studied by the methods of wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and Raman spectra. Compared with sample prepared at ambient pressure, high pressure treatment makes the hydrogen-bonded sheets pack more closely and thus enhanced CH 2 vibration out of the hydrogen-bonded sheets. After high pressure treatment, it is observed that all changes of C-C related vibration modes in nylon 6 are similar with ones in nylon series when the CH 2 sequence number increased, from which it is deduced that high pressure treatment reduces the effects of amide group on the chain conformation of nylon 6.

In this work, the effects of two silane type external donors, Ph 2 Si(OCH 3 ) 2 (DPDMS) and dicyclopentyldimethoxysilane (DCPDMS) on propylene slurry polymerization in the presence of hydrogen with a MgCl 2 /TiCl 4 /DIBP - Al(C 2 H 5 ) 3 catalyst system were investigated, and the tacticity distribution and molecular weight distribution (MWD) of polypropylene (PP) were further regulated by using silane/ether (ROCH 3 , R = n-Bu, i-C 8 H 17 ) composite external donors. The tacticity distribution of PP, as revealed by successive self-nucleation and annealing (SSA) thermo analysis of the polymer, is markedly changed by the external donors. DCPDMS shows much stronger effects than DPDMS. Addition of the ether as an auxiliary external donor in MgCl 2 /TiCl 4 /DIBP-TEA/silane (DPDMS or DCPDMS) lead to further increase in catalytic activity and isotacticity of PP, and changes in tacticity distribution. By using the composite external donors, PP with both higher isotacticity index, lower molecular weight or narrower molecular weight distribution was prepared at high activity. Effects of the external donors on the active center distribution were discussed based on the results of deconvoluting the MWD curve with multiple Flory “most-probable” distributions, and possible mechanism of the external donor effects was proposed.

Hydrophilic copolymers based on acrylamide and diallyldimethylammonium chloride including those modified with montmorillonite have been synthesized, characterized by capillary viscometry and FTIR, and their flocculation efficiency has been tested. As an inorganic modifier sodium montmorillonite has been used. In situ copolymerization reactions were carried out as thin-layer processes in aqueous solutions. The results from numerous tests based on model water suspensions (talc and coal fine) confirm high flocculation efficiency of the investigated copolymers. The new type of acrylamide copolymers allow to ascertain that their synthesis in the presence of layered silicates can improve flocculation performance in comparison with unmodified copolymers. These copolymers may potentially compete with acrylamide copolymers in terms of price and flocculation effectiveness.

Experimentally, the fluorescent intensity of the pyrene-functionalized fluorescent film is reduced by introducing nitrobenzene. In order to fulfill the functional reason of this quenching effect, a molecular dynamics simulation is adopted in this paper. The simulation finds that the structural modification of the pyrene molecules in the film is the main reason for the quenching effects. Result reveals that, in the vacuum environment, the distance between a pair of pyrene ring centers distributes from about 4 Å to 10 Å, and a large number of distances populate at 5.3 Å, which is a suitable distance for excimer emission. The introduction of nitrobenzene results in a decrease of the population of pyrene molecules within that distance, indicating a decrease of excimer emission of the film. In addition, the pyrene molecule rings in the film prone to adopt quasi-coplanar structure in the vacuum, but less likely arrange into a coplanar structure when nitrobenzene is introduced. Study clearly indicates that the structural changes are all caused by the insertion of the incoming nitrobenzene molecules into the previously coplanar pyrene rings. Finally, length and orientation of chain are also analyzed. All the expectations from the simulation studies are basically consistent with the experimental observations.

Various polyacrylamide (PAAm) - Kappa Carrageenan (κC) composite gels were prepared from acrylamide (AAm), N,N- methylenebisacrylamide (BIS) and different κC contents by free radical crosslinking copolymerization in water. Pyranine (P) was introduced as a fluorescence probe, and scattered light, I sc , and fluorescence intensities, I, from these gels were monitored during drying at different temperature. The fluorescence intensity of pyranine increased as drying time is increased for all samples. The behavior of I was quantified using the Stern-Volmer equation with moving boundary diffusion model. Desorption coefficient, D increased as temperature was increased for a given κC content. Supporting gravimetrical and volumetric experiments were also carried out during drying of PAAm-κC composite gels. The energy, △E values were measured for the drying processes for each κC content gel by using fluorescence, gravimetrical and volumetric methods, respectively. It is understood that △E values increase by increasing κC content, indicating that energy needs for the drying of high κC content gel is larger than low κC content gel.

Poly(vinylidene fluoride)-silver nanoparticle (PVDF-Ag) composites were synthesized by in situ reduction of silver salt using dimethylformide (DMF) as both a solvent and a reductant. The crystalline properties (e.g., crystallinity and the types of crystals) of the composites were characterized. It was shown that PVDF in the composites had a higher melting temperature than pure PVDF, and the α phase crystal in the composites became more stable with an increase in the amount of silver nanoparticles. The mechanical properties and morphologies of the composites were also investigated. It was noted that the PVDF-Ag composites have better mechanical properties when silver nanoparticles were added. The increase in toughness could be attributed to the formation of continuous structure between PVDF and silver particles.

A novel type of protopropic tautomerism proceeds in macromolecules of binary copolymers of maleic anhydride (MA) with vinyl acetate (VA) and vinyl chloride (VC) giving rise to spontaneous formation of dynamic micro structural heterogeneity which consists of several tautomeric forms: succinic anhydride rings, VC and VA units along with unforeseen enol (en) and dienol (den) furan derivatives (33 mol%). The arising hydrogen bonds close the ring generating quasi-aromatic structures simultaneously. The en and den tautomers form charge-transfer complexes with O- and N- nucleophiles. Mechanism of MA radical copolymerization with VC including polyaddition of molecular monomer complexes both in the ground state and in their biradical resonance structures has been proposed. The investigations were carried out using infrared spectroscopy (IR-), electron, nuclear magnetic resonance spectroscopy ( 1 Н and 13 С NMR), differential thermo analysis, mathematical microstructure modelling etc.

Cross linking of the HDPE was performed with high energy electron beam. EPR spectroscopy was used to study the life time of unpaired electron in the irradiated samples. Dielectric constant and dielectric strength almost remained unchanged but, volume resistively and dissipation factor increased and decreased respectively, after irradiation. The results shows that the dissipation factor is going to be recovered slowly with the storing time at room temperature. It is believed that variation of some electrical properties during time after irradiation are due to the effects of free radical and charge trapping remained in the bulk of material.

Three novel sulfur-containing polyurethanes (PUs) as macrophotoinitiators, hydroxyl-terminated PUa and PUb, and amino-terminated PUc, were synthesized through polycondensation of a novel diamine 4,4’-bis[(4- amino)thiophenyl]benzophenone (BATPBP), isophorone diisocyanate (IPDI) and N-methyldiethanolamine (MDEA). The beznophenone and coinitiator amine structures were successfully introduced into the backbones of PUs. FT-IR, 1 H NMR, GPC and DSC analyses confirmed their structures and properties. UV-vis spectra indicate that the macromolecular structure nearly has no influence on their UV-vis absorptions. A trifunctional monomer of trimethylolpropane triacrylate (TMPTA), initiated by these macrophotoinitiators with a low-molecular-weight photoinitiator system (benzophenone/MDEA) as the reference, was studied through photo differential scanning calorimetry (photo-DSC). The results show PUa is the most efficient photoinitiator and the molar content of coinitiator amine in PUs has an important effect on their photoefficiency.

The paper reviews the modification and shaping of electron beam irradiation on carbon nanotubes (CNTs), as well as how this could be potentially useful for electron beam modification of nanotubes. The influence of irradiation on the mechanical property, electrical property and field effect of CNTs is discussed. Several examples are given with particular emphasis on the cutting, shaping and welding of CNTs by the electron beam in an electron microscope. It is shown that the change of incident electron energy and ambient temperature will lead to the different irradiation results. It is expected that electron irradiation studies will continue to play an important role in the research on CNTs.

Nylon 11 nanocomposites with different montmorillonite loadings were successfully prepared by melt compounding. XRD and TEM show the exfoliated nanocomposites are formed at low montmorillonite concentration (less than 2 wt%) and the intercalated nanocomposites are obtained at higher montmorillonite contents. TGA shows that the thermal stability of the nanocomposites is improved by 27 °C when the montmorillonite content is only 2wt%. At the same time, The crystallization behavior of nylon11/montmorillonite nanocomposites has been studied by means of XRD, DSC.The Avrami equation described well the isothermal crystallization behavior of nylon11 and nylon11/montmorillonite nanocomposites. The results showed that the montmorillonite acted as the nucleating agent and facilitated the crystal growth rate of nylon 11 matrix. The incorporation of montmorillonite did not change the crystal morphology of nylon 11 but increased the crystallization temperature and decreased the crystallization activation energy, which lead to a easy crystallization of nylon11. Mechanical testing shows that the Izod impact strength of all nanocomposites are higher than that of the neat nylon 11, but the tensile strength of the nanocomposites decrease at low nanofiller concentrations (less than 8wt%) and then increased, when the montmorillonite content is 10wt% ,the tensile strength of the nanocomposite is 5% improved than neat nylon 11. This is may be due to the strong interaction between the nylon 11 matrix and the montmorillonite interface.

In this work, the effect of different nanographite such as expandable graphite (EG) and exfoliated graphite nanoplatelets (xGnP) on the electrical and thermal properties of nanocomposite thermoplastic elastomer gels prepared from a poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) imbibed with an EBcompatible paraffin oil was investigated. The electrical properties have been studied as a function of variation of nanoparticles in the frequency range of 5 2 to 10 7 Hz. For all the nanoparticles studied, the dielectric constant increases as the volume content of the nanoparticles in the TPE gels increases. The increase in dielectric constant was fairly smooth with no clear dielectric singularity in the concentration range studied. However, the percolation threshold in the dielectric spectra was clearly seen. The incorporation of a small quantity of nanographite improved the thermal stability of the swollen midblock of TPEGS, since the particles dispersed in this region, thereby increasing the distinct region of oil degradation temperature but no improvement on SEBS matrix. The results showed that size, shape and agglomeration of the particles with high amount of oil in SEBS system played a role in the dielectric properties and thermal stability.

The wear and friction performance of GUR 1020 grade ultrahigh molecular weight polyethylene (UHMWPE) polymer was studied in distilled water, HASS (Hank’s balanced salt solution) and several protein lubrication environments. Wear tests were carried out using polymer pin -on AISI 304L stainless steel disc apparatus. Tests conditions were room temperature, 40N, 80N and 120N applied loads and 0.5 m/s sliding speed. For the range of load and speed value of this work, the coefficient of friction and wear rate for UHMWPE polymer decreases with the increase in applied load values. The coefficient of friction is highest and the specific wear rate values is lowest under HASS +HA solution lubricant. The average specific wear rate values for UHMWPE polymer under distilled water and HASS+HA (Hank’s balanced salt solution with Hyaluronic acid) lubrication conditions are in the order of 9x10 -15 m 2 /N and 3x10 -15 m 2 /N respectively. The wear mechanism includes abrasion and adhesive processes.

The copolymerization of acenaphthylene with methylmethacrylate, ethylmethacrylate, butylmethacrylete, iso-butylmethacrylate and cyclohexylmethacrylate has been carried out in tetrahydrofuran at 323 K and the composition of the copolymers has been determined by size exclusion chromatography using a double RI-UV detector system. Several methods have been applied to obtain the reactivity ratios of the copolymerization process. The glass transition temperature of the copolymers has been obtained by DSC and the thermal stability has been studied by thermogravimetry. Analysis of the degradation volatile products reveals that copolymers degrade mainly by depolymerization.

To determine the influence of particle size on the specific surface area of hypercrosslinked poly(styrene-co-divinylbenzene) (PS) microspheres, two methods were chosen for preparation of particles, suspension and dispersion polymerization. While the former method produced hundred micrometer-sized PS-S microspheres, the latter yielded PS-D particles of ca. 1-μm size. Dispersion copolymerization of styrene (St) and divinylbenzene (DVB) in ethanol was stabilized by (hydroxypropyl)cellulose (HPC) and initiated with dibenzoyl peroxide (BPO). Monodisperse 1.4-μm PS-D microspheres were prepared only in the presence of 3.6 wt% HPC. All microspheres were chloromethylated with chloromethyl methyl ether (CMME), chloromethyl ethyl ether (CMEE) or chloromethyl octyl ether (CMOE) to investigate the effect of the chloromethylation agent on the specific surface area of microspheres. Chloromethylated microspheres were hypercrosslinked in 1,2-dichloroethane (DCE) in the presence of a Lewis acid (SnCl4). The effects of the crosslinker (DVB) and DCE/microsphere ratio on properties of the product were studied. The specific surface area, pore volume and pore size distribution of the microspheres were analyzed by dynamic desorption of nitrogen, cyclohexane regain and mercury porosimetry.

A set of polyurethanes containing isosorbide units were synthesized by polymerization in solution from HDI and MDI diisocyanates and 1,4-butanediol (BD), isosorbide (Is) or diisosorbide diurethanes (Is 2 HDI and Is 2 MDI) as diols. The thermal properties and stability, and crystal structure of the polyurethane homopolymers and copolymers containing isosorbide were evaluated and compared with those of the polyurethane analogues entirely made of BD. Incorporation of isosorbide produced significant changes in T g , T m and T d but no noteworthy differences were found between copolymers made from Is or Is 2 monomers. Degradation assays revealed that incorporation of Is units increased slightly the hydrolysis rate.

Structurally well-defined core-shell particles were prepared by modifying the surface of silica with initiators for atom transfer radical polymerization (ATRP), and followed by using these initiator-modified particles as ATRP macro-initiators for methyl methacrylate. These particles were characterized with Fourier-transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA) and scanning electron microscopy (SEM). The tethered polymer chains on the grafted silica particles were cleaved with hydrofluoric acid and measured with gel permeation chromatography (GPC). The results showed that poly(methyl methacrylate) (PMMA) chains grew from the particle surfaces in form of individual particles comprising of a hard silica core and a well-defined, densely grafted outer polymer layer. Diglycidyl ether of bisphenol-A (DGEBA) based epoxy resin was toughened with various doses of the synthesized PMMA-grafted silica particles. Resulting composite materials were characterized by tensile testing, SEM, dynamic mechanical analysis (DMA) and TGA. The results indicated that the incorporation of the core-shell particles improved the toughness of the composites without any significant deterioration of its thermal properties.

In this work, nanocomposites of low density polyethylene (LDPE) / multiwall carbon nanotubes (MWCNTs) were prepared using melt blending. The effects of CNT aspect ratio, CNT loading, CNT chemical modification and the presence of a compatibilizer (maleated polyethylene) on morphology, mechanical and thermal properties of the CNT/LDPE composites were studied. Different MWCNTs were used: long CNT (LCNT); COOH modified CNT (MCNT) and short CNT (SCNT). FE-SEM images of produced nanocomposites show agglomeration of the MWCNTs. Addition of compatibilizer to both LCNT and MCNT nanocomposites improved their dispersion in the LDPE matrix. Yield strength and modulus increased with loading of various MWCNTs. However, ultimate strength, percent elongation and toughness reduced significantly for CNT loadings of 2% CNT and higher. The addition of maleated PE resulted in improvements of Young’s modulus, yield strength and ultimate strength but no impact on elongation at break or toughness. Addition of compatibilizer did not affect the crystallinity of the produced nanocomposites. In general, the use of CNT with high aspect ratio and the addition of compatibilizer and chemical modification improved the dispersion of MWCNTs and consequently improved most of the mechanical properties except elongation at break and toughness.

The present work describes the statistical process optimization of a lowcost production process of PLA using organometallic (stannous octoate) compounds. The process optimization for both lactide and polylactide, was developed by factorial design and response surface methodology. The influence of different experimental parameters such as reaction temperature, time, concentration of catalyst and co-initiator concentration on the yield of lactide and polylactide has been evaluated. There are many studies reported on the synthesis of polylactide but no earlier study exists for the application of statistical analysis in determining the interactions among the process variables for lactide and polylactide production. Central composite experimental design with multiple linear regression has been used to estimate the coefficients of the polynomial model equation for the yield(s) of both lactide and polylactide. The statistical significance of polynomial model equation was validated by F test (ANOVA). Determination coefficient (R 2 ) values found to be 0.913 and 0.958 for lactide and polylactide respectively, states that predicted values were in good agreement with the experimental values. Results of the statistical analysis showed that the model fits in all cases. Above synthesised polymer was characterized by FT-IR, 1 H-NMR, DSC and GPC to confirm the polymer structure and properties.

Waterborne siloxane-containing polyurethanes (WSPU) were prepared by polyaddition reaction using poly(tetramethylene oxide)glycol (PTMG), polyethylene glycol (PEG), and α,ω-aminopropyl polydimethylsiloxane (APDMS) as mixing soft segments; 2,2-di(hydroxymethyl)propionic acid, as a hydrophilic chain extender; 1,4-butanediol and isophorone diisocyanate as hard segment; triethylamine as a neutralization agent. The thermal properties of WSPU films were analyzed by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermal gravimetric analysis (TGA). The mechanical properties of WSPU film were also investigated. Water vapor permeability (WVP) was examined according to GB_T 12704-1991. The DSC and DMA results indicated that there is a micro-phase separation in the WSPU film. The incorporation of APDMS into PU made the thermal stability of hard segment worse while that of soft segment better. The elasticity of WSPU was improved when the APDMS content was not more than 10%, the vapor permeability of coated fabric increased firstly and then decreased as the APDMS content increased, which was resulted from the hydrophilicity change and microstructure change of membrane. When 10% APDMS was incorporated into the WSPU, the WVP of coated fabric was 2130.15 g/(m 2 ·24h), equal to one coated with a widely used solvent-based PU sample (UECCOAT), and the water resistance (WR) reached 30.0 KPa.

The novel poly(acrylic acid)/poly(ethylene oxide) (PAA/PEO) blend nanofibers at 100/0, 80/20, 50/50, 20/80 and 0/100 weight ratios were obtained via electrospinning process. Intermolecular interactions and compatibility of blend fibers were studied by Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC). It was found that the free-hydroxyl groups, the bonded hydrogen hydroxyl groups and the carbonyl groups absorption bands in the electrospun PAA/PEO fibers shifted with the increase in PEO percentage in the blend. DSC measurements showed the melting point, the glass transition temperature, the melting enthalpy and the crystallinity percentage of pure polymer nanofibers were different compared with blend nanofibers. The results suggested that intermolecular interactions occurred in the electrospun PAA/PEO nanofibers. These interactions made PAA/PEO blends miscible at above-mentioned weight ratios. Additionally, the morphology and the average fiber diameter were investigated using scanning electron microscope (SEM) analysis, which indicated beadless fibers with diameter range of 110 to 280 nm. It was observed that the uniform fibers with the smaller average diameter were obtained in PAA/PEO blends containing PAA dominant content. Finally, the SEM results suggested that the formation of pure PAA nanofibers with concentration of 5 Wt. % would not occur. Whereas, in the same concentration, pure PEO and PAA/PEO blend nanofibers with no bead defects were obtained.

New acid-base polymer blends based on sulfonated poly(phenylene oxide) (SPPO) as the proton-conducting component and poly(ether imide) (PEI) as the basic component were considered for use as proton-exchange membranes (PEM). The obtained blend membranes had a higher thermal stability and a higher glass transition temperature (T g ) than the pure SPPO, as revealed by TGA and DSC. The morphology of blend membranes indicated that PEI was highly compatible with SPPO polymers because of the formation of hydrogen bonds between the sulfonated acid and PEI. Although the blend membranes exhibited a lower water uptake and lower proton conductivity than the pure SPPO membrane, the PEI component improved the dimensional stability, mechanic properties, and especially inhibited methanol permeation. The methanol permeability coefficient of the blend membrane with 30 wt.% PEI content was 9.68×10 -8 cm 2 /s, which is lower than that of the pure SPPO and just one tenth of that of Nafion ® 112. This considerable reduction in methanol crossover revealed the feasibility of the blend membranes as promising electrolytes for direct methanol fuel cells.

Polylactic-acid (PLA) and PLA-clay fibres have been produced from solution of 1,1,1,3,3,3-hexafluoro-2-propanol by electrospinning. Nanoclays having different aspect ratio, namely a montmorillonite and a sepiolite, have been added and dispersed within the polymer matrix in order to enhance the thermal stability and air permeability of PLA. The influence of the polymer molecular weight, the solution viscosity and conductivity on the morphology of the fibres has been investigated. Electron microscopy has shown that fibre diameter and the presence of beads defects in the fibres depend on the type of clay added to the polymer matrix. The thermal stability in nitrogen and in air has been drastically enhanced for the presence of the clays as compared with neat polymer. Finally, permeability tests performed on the electrospun condensed fibres pointed out that PLA-clay fibres exhibit a lower permeability to air (up to 90%) with respect to neat PLA fibres.

Present study describes the preparation and characterization of crystal violet modified-montmorillonite clay nanocomposites by latex blending technique. Coagulation of the latex-clay slurry produced nanocomposites master batch. The master batch was compounded with Styrene Butadiene rubber (SBR). WAXD and TEM provided the evidences of formation of nanocomposite. Remarkable improvements in the mechanical properties were found by addition of small amount of modified clay.

Experimentally, the fluorescent intensity of the pyrene-functionalized fluorescent film is reduced by introducing nitrobenzene. In order to fulfill the functional reason of this quenching effect, a molecular dynamics simulation is adopted in this paper. The simulation finds that the structural changes of the pyrene molecules in the film are the main reason for the quenching effects. Result reveals that, in the vacuum environment, the distance between a pair of pyrene ring centers distributes from about 4 Å to 10 Å, and a large number of distances populate at 5.3 Å, which is a suitable distance for excimer emission. The introduction of nitrobenzene leads to a decrease of the population of pyrene molecules within that distance, indicating a decrease of excimer emission of the film. In addition, the pyrene molecule rings in the film prone to adopt a quasicoplanar structure in the vacuum, but less likely arrange into a coplanar structure when nitrobenzene is introduced. Study clearly indicates that the structural changes are all caused by the insertion of the incoming nitrobenzene molecules into the previously coplanar pyrene rings. Analysis of structure factor and X-ray scattering also indicates that the structural modification of the pyrene molecules surely reduces the fluorescent intensity of the pyrene-functionalized film in the nitrobenzene environment.

Carbon nanofibers were fabricated by electrospinning with various concentrations of MnO 2 , carbonization and activation processing for supercapacitor applications. Microstructure and electrochemical properties were characterized by scanning electron microscopy (SEM), the 4-point probe method, and a battery cycler system. It was observed that 8-20 wt.% MnO 2 /PAN nanofibers had 190- 260 nm diameters. The diameter decreased with increasing MnO 2 concentration, but it increased for concentrations greater than 16 wt.%. The 16 wt.% MnO 2 solution produced the nanofibers with the smallest diameter. The nanofibers showed capacitor characteristics when fabricated into electrodes, and their electrical conductivity and capacitance increased with increasing MnO 2 concentration. The 20 wt.% MnO 2 /PAN carbon nanofibers showed the highest electrical conductivity value (2.82×10 -3 S/cm) and the highest capacitance value (186.28 F/g), which indicates their potential for development of supercapacitor electrodes.

The short glass fiber (SGF)/polypropylene (PP) and ethylene-1-octene copolymer (POE)/SGF/PP foam composites were prepared by extrusion and subsequent post-foaming process in designed dies. The compatilizers, maleic anhydride grafted PP (PP-g-MAH) and maleic anhydride grafted POE (POE-g- MAH), were employed to improve the performance of the foam composites, respectively, and their influences on the cellular structures, interfacial morphologies and mechanical properties of PP foam composites were investigated. It was found that the compatilizers resulted in modified PP foam composites characterized by uniform cell size distribution, reduced cell size and increased cell density except POE/SGF/PP with POE-g-MAH. The obvious enhanced SGF-matrix interfacial bonding was observed from the SEM examination, and POE-g-MAH also facilitated the compatibility between elastomeric particles and matrix. Testing results indicated that, by the introduction of PP-g-MAH or POE-g-MAH, the mechanical properties of PP foam composites were significantly improved, and it seemed that the PP-g-MAH was more effective in strengthening the flexural and compressive strength while POE-g-MAH greatly increased the impact toughness.

On the basis of commercially available trimethylolpropane (TMP) three six-membered ring carbonates were prepared, substituted with reactive side groups: a chloroformate (2a), an imidazolyl carbamate (2b) and a phenyl carbonate (2c). Their synthesis and characterizations are described and compared to known ring carbonates with reactive side groups. Starting from 2a-c orthogonal couplers 3a and 3b were synthesized for conversion under mild reaction conditions. In a model reaction 2-azidoethyl 2-N-acetylamino-2-deoxy- -D-glucopyranose and tertbutyl- N-(3-aminopropyl) carbamate were linked with coupler 3a via a 1,3-dipolar cycloaddition and a nucleophilic ring-opening reaction. This coupling principle can be used for the preparation of multifunctional polymers or surface coatings at ambient conditions.

Drawn composite thin film based on thermotropic liquid crystalline polymer (TLCP) and polypropylene (PP) was annealed at 130 °C at different times. The influence of annealing time on microstructural and mechanical properties of the composite film has been studied. The correlation in mechanical properties and their microstructural parameters has also been investigated. X-Ray diffraction results reveal that the smectic mesophase transforms progressively into the monoclinic phase as annealing time is increased. Consequently, the true crystallinity (X c ), crystal thickness (L) as well as relative level of molecular orientation of PP crystalline phase in the annealed TLCP/PP films are increased significantly. Also, the TLCP fibrils have no influence on the microstructure of PP crystalline phase. The apparent crystallinity (X c,a ) of PP phase evaluated by DSC also increase significantly with annealing time. As a result, the increases of these microstructural parameters coupled with the reinforcement of TLCP fibrils could be contributed directly to the remarkable enhancement of mechanical properties of the annealed TLCP/PP film in both machine (MD) and transverse (TD) directions. The correlation of moduli with microstructural parameters (X c , X c,a and L) exhibits nonlinear relations. However, the relative level of molecular orientation is a more suitable parameter to correlate with the improvement of mechanical properties of the annealed TLCP/PP film. Finally, this work presents that the mechanical properties of the TLCP in situ reinforced thermoplastics can be significantly enhanced via a simple thermal treatment.

Poly(ε-caprolactone) (PCL) grafted on silicon wafer with different thickness (10 to 100 nm) were prepared by surface-initiated ring-opening polymerization (ROP). The morphologies, crystallinity, and crystallization rate of different thickness thin films have been investigated by atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). The nascent morphology of the as polymerized 15 nm film was found to be nodular structure form. As the film thickness increased, the nodular structures gradually aggregated to form flat-on lamellae. When the film thickness reached 100 nm, the surface of silicon wafer was covered with a whole layer of flat-on lamellae. The isothermal crystallization study on 100 nm film had shown that the tethered PCL chains could only crystallize in the form of flat-on lamellae. FTIR study had showed that the crystallinity decreased significantly with the film thickness decreasing, while the half-crystallization time increased as the film became thicker. The halfcrystallization time increase of thicker film was supposed to relate with the degree of chain entanglement in the tethered brushes.

Combining the microemulsion polymerization with UV direct initiation, an efficient method for polymerization of AM with high polymerization rate and conversion, low polymerization temperature, high purity of product and simple radiation equipment was developed. In the absence of initiator and under UV radiation, the polymerizations of AM inverse microemulsion system with high monomer content and low emulsifier content were successfully accomplished at low temperature (24~30 °C) and PAM with high purity and high limiting viscosity [η] was obtained. The polymerization rate was fast and the conversion reached to higher than 85% in 30 minutes. Based on the abundant experimental results, the reasonable polymerization mechanisms were proposed as follows: the AM participated in the initiation reaction and the main initiation locus was the emulsifier layer. Rp and [η] were weakly influenced by temperature due to the low apparent activation energy of the reaction (Ea = 12.98 kJ/mol). The polymerization kinetics of Rp was expressed as the following: Rp = [IUV] 0.4972 [M] 1.5048 [E ]-0.5731. The Rp order with respect to [M] is equal 1.5048 which confirms the conclusion that the monomer participated in the initiation reaction.

The ring-opening polymerization of ethylene carbonate was examined using ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF 4 ) and 1-butyl-3-methylimidazolium chlorozincate ([bmim]Cl-(ZnCl 2 ) x ), as polymerization catalysts. It was shown that the polymerization was accompanied with decarboxylation and chain cleavage reaction. As the reaction time increased, the monomer conversion increased and the content of ethylene carbonate units in the resultant polymer decreased, while the polymer molecular weight increased at first, reached a maximum and then decreased. It was also found that not only the polymerizing activity of the [bmim]Cl-(ZnCl 2 )x but also its performance for suppressing the decarboxylation and chain cleavage increased with the molar fraction of ZnCl 2 . It was deduced that the catalytic performance of ionic liquids mainly depended on their inorganic anions and that the larger the amount of these anions in the reaction system, the better the catalytic performance. The polymerizing activity of ionic liquids was much higher than conventional catalysts often used for the polymerization of ethylene carbonate.

A novel all-polymeric material with high dielectric constant (k) has been developed by blending poly(vinylidene fluoride) (PVDF) with polyacrylamide (PAM). The dependence of the dielectric constant on frequency and polymer volume fraction was investigated. When the weight fraction of PAM is 1wt%, the dielectric constant of the blend could be up to 24, and the dielectric loss tanδ can be lowered to 0.06. The SEM investigations suggest that the enhanced dielectric behavior originates from significant interfacial interactions of polymer-polymer. XRD and FTIR demonstrate that blending PAM with PVDF affects the crystalline behavior of each component. Our finding suggests that the created high-k polymeric blends represent a novel type of material that are flexible and easy to process, and is of relatively high dielectric constant and high breakdown strength; moreover find applications as flexible electronics.

Polymer organic-inorganic hybrid nanofibers constitute a new class of materials in which the polymeric nanofibers are reinforced by uniformly dispersed inorganic particles having at least one dimension in nanometer-scale. In the present study, nanofibrous mats of neat and nanocomposite polyacrylonitrile (PAN) were fabricated by electrospinning process. Electrospun PAN and PAN/Na-MMT fibrous mats with the respective mean fiber diameter of about 220 and 160 nm were prepared. The influence of the clay-montmorillonite on the morphology and diameter of nanofibers was investigated by means of scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. The microscope techniques results suggested that the PAN/Na-MMT composite nanofibers showed the lower mean fiber diameter than the neat PAN nanofibers. Besides, the difference in nanoclay-content has a slight effect on the distribution of fibers diameter. Thermogravimetric analysis (TGA) results suggested that the introduction of clay-nanomaterials improve the decomposition onset and residual weight percentage of mats at about 31°C and 13 %, respectively. The results of X-ray diffraction (XRD) confirmed that the clay-montmorillonite layers were exfoliated in the polymer matrix. The exfoliation of clay layers was further supported by transition electron microscope (TEM) observations.

MgCO 3 and 2ZnCO 3 ·3ZnO·4H 2 O (AZC) as flame-retardants and smoke suppressants for flexible poly(vinyl chloride) (PVC) was evaluated using limiting oxygen index (LOI), smoke density rating (SDR) tests, scanning electron microscopy (SEM) and thermogravimetry analysis (TGA). The activation energy (E a ) of the original and flame retardant PVCs’ degradation processes was calculated by the Vyazovkin method. The results showed that the AZC can be used as a synergistic agent for MgCO 3 as flame retardants agent of flexible PVC. The composites of MgCO 3 and AZC cannot only decrease the initial decomposition temperature and increase the weight loss rate in the first stage, but also can promote the char formation in the second stage. The AZC decreased the Ea of the degradation reaction of PVC in the first stage and MgCO 3 increased the Ea in the second stage, which means that the AZC combined with MgCO 3 , catalyzed the dehydrochlorination, promoted the early crosslinking for the PVC compound and improve the stability of the char residue. The SEM results also show that the char residue of MgCO 3 /AZC treated sample has a continuous and denser structure, which can be used as a barrier for the PVC bulk.

A novel poly(amic acid) containing 1,10-phenanthroline (PPHPA) was first synthesized by the polycondensation of 4,4'-oxydiphthalic dianhydride (ODPA) with 5,6-diamine-1,10-phenanthroline (DAPH). Three polymeric complexes were first prepared by the reaction of polymer (PPHPA) with NiSO 4 , CuSO 4 , and NdCl 3 , respectively. The structures of the polymer and the complexes were characterized by IR, 1 H-NMR, and elemental analysis. The magnetic behaviors of these complexes were measured as a function of magnetic field strength (0-50 kOe) at 5 K and as a function of temperature (5-300 K) at a magnetic field strength of 30 kOe. The results show that PPHPA-Ni 2+ and PPHPA-Nd 3+ were soft ferromagnets, whereas PPHPA-Cu 2+ exhibited the features of an antiferromagnet.

Reaction products of Oxalamide (OD) with a 8- and 12-molar excess of ethylene carbonate (EC) and propylene carbonate (PC), characterized by an enhanced thermal stability due to the presence of Oxalamide arrangement, were used as polyol components for obtaining foamed polyurethane plastics. As an isocyanate agent diphenylmethane-4,4’-diisocyanate was used. The obtained new foamed polyurethane plastics are characterized by a slight water uptake, good stability of dimensions and an enhanced thermal stability.

Silk fibroin (SF) microspheres containing a model drug were prepared by a simple water-in-oil emulsification-diffusion method. Aqueous SF solution and ethyl acetate were used as water and oil phases, respectively. Methylene Blue was used as a water-soluble model drug. Effect of drug content on microsphere characteristics, drug loading efficiency and drug release behavior was determined. Scanning electron microscopy revealed that drug-loaded SF microspheres were spherical in shape with a smooth surface. The SF microspheres showed predominant random coil SF conformation. All drug loading efficiencies were approximately 50%. An increase in drug/SF ratio could lead to an increase in %drug release and surface erosion after the drug release test. Drug release from SF microspheres is due to SF matrix swelling and surface erosion processes.

Acrylic acid (AA) was grafted firstly onto high density polyethylene (HDPE) by in-situ chlorinating graft copolymerization (ISCGC), so a graft copolymer composed of chlorinated polyethylene (CPE) as backbone and poly (acrylic acid) (PAA) as branched chains was synthesized. And subsequently the preparation of its carboxylated ionmers was studied. This work was focused on discussing the reaction process for grafting AA onto HDPE by ISCGC and the preparing of carboxylated ionmers of CPE. In this paper, the structure of graft copolymer and the ionomer were characterized mainly by FT-IR, gel permeation chromatography (GPC) and graft degree (GD). The influence factors which related to the main and side reactions, including the monomer concentration, chlorine contents of the product, and reaction temperature were investigated. Additionally, effects of these factors on reaction process controlling were described. The aim of above is to investigate how CPE-cg-PAA and its sodium-salt ionomer were prepared.

Based on the FTIR spectral changes, the miscibility of some nanocomposites based on starch, polyvinyl alcohol and treated multilayered silicate, was qualitatively estimated. The FTIR spectroscopy provide evident gross/small spectral changes as well as appreciable spectral shifts mainly in those spectral range that defines hydroxyl O-H vibrations (3600- 3000 cm -1 ), water absorbtion (1800 - 1500 cm -1 ) , the morphological order degree and the interaction with multilayered silicate and (1192 - 950 cm -1 ). Based on the observed spectral modifications it can be estimate that high miscibility do exist between the components of the studied nanocomposites.

The effect of surface modified fillers based on montmorillonite on rheological and mechanical properties and thermal stability of high-molar mass polydimethylsiloxane matrix was evaluated. Silicone rubber/clay composites were prepared via homogenisation on open two roll-mill followed by torque measurement at two different temperatures. At 30 °C and 100 °C the torque did not extremely differ excepting the mixtures containing Cloisite 15A where it achieved the maximum at 3 phr montmorillonite content, but the tensile strength reached the similar values in all mixtures. Thermogravimetric analysis was utilized to find out the differences in weight decay of composites in silicone rubber/montmorillonite mixtures and in unfilled silicone rubber. Synergism of fillers was also studied and led to tensile strength increase.

The cell wall material of Caragana sinica was fractionated by successive extractions with distilled water at 80 °C for 2 h, 70% ethanol, 70% ethanol containing 1% NaOH, 1 M KOH, 1 M NaOH, 3 M KOH, and 3 M NaOH at 75 °C for 3 h. The sequential treatments resulted in a total dissolution of 86.7% of the original hemicelluloses and 80.1% of the original lignin from dewaxed C. sinica. The current results showed that the four alkali-soluble hemicellulosic preparations, comprising almost 80% xylose of the total neutral sugars, were more linear and acidic, but lower molecular weights (Mw, 28420-55140 g/mol) than the other two organosolv-soluble hemicelluloses (Mw, 57930-96470 g/mol). The 1 M KOH-soluble hemicellulosic fraction was characterized by sugar analysis and 1D, 2D NMR spectroscopy and was found to be composed of a linear (1→4)-β-D-xylopyranosyl main chain with a 4 Omethylglucuronic acid substituting the C-2 position of approximately every eight xylose unit, which is typical of a hardwood acidic 4-O-methylglucuronoxylan (MGX).