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In this work, a three-phase model consisting of crystalline, mobile amorphous and rigid amorphous phases (RAP) was used to describe the structural formation of poly(trimethylene terephthalate) (PTT) at various crystallization conditions. The variation in thickness and fraction of each phase was studied on both crystallization temperature T c and crystallization time t c effects from...
Fourier transform infra-red spectroscopy was used to study the specific interactions between three aliphatic dicarboxylic acids, namely succinic acid (SCA), suberic acid (SBA) and dodecanedioic acid (DDA), and two proton-accepting polymers, poly(2-vinylpyridine) (P2VPy) and poly(N-vinyl-2-pyrrolidone) (PVP). P2VPy interacts with the acids through hydrogen-bonding interaction as well as ionic interaction,...
This paper reports on an efficient 'in-situ' one pot synthesis of an initiatior/ligand adduct, which can be used to initiate the anionic polymerization of methyl methacrylate in toluene at 0 o C. Predominantly syndiotactic PMMA is formed.
Semicrystalline ethylene/1-octene copolymers (P(E-co-O)) with a content of 1-octene comonomer, w O , between 7 and 24wt% and a crystallinity X c between 50 and 10% and a high-density polyethylene (HDPE, X c =70%) were studied in the temperature range between 115K and (300-350)K by positron annihilation lifetime spectroscopy (PALS) and dynamic mechanical analysis (DMA). The...
A computational method is developed to evaluate the relative amount of mesophase of polymer fibers from their two-dimensional (2D) wide-angle X-ray scattering (WAXS) patterns. This is achieved by first evaluating the percentage of oriented phases (POPs) from a 2D WAXS pattern. If there exists a crystalline phase, crystallinity is subtracted from the POPs to obtain the mesophase percentage. If no crystalline...
Small angle neutron scattering was used to in situ study the aggregated structures formed in the course of the polymerization of butadiene and isoprene in deuterated n-heptane. The samples were designed to have equal degrees of polymerization. These measurements showed, at low Q, that the start of the butadiene propagation event was accompanied by the presence of highly extended large-scale structures...
The effect of incorporating a small amount of alkali metal alkoxides into a diene polymerization catalyzed by n-butyllithium in the presence of a polar modifier was investigated. It was found that the addition of sodium alkoxide significantly enhanced the polymerization rate of the monomers (1,3-butadiene, isoprene and styrene) and increased the vinyl content of the resulting polymers. It was also...
The thermodynamic phase behaviour of blends composed of two random copolymers of polystyrene-co-methyl methacrylate (SMMA) and polystyrene-co-acrylonitrile (SAN) was studied using a modified Flory's equation of state (EOS) theory. Light scattering measurements indicated that SMMA and SAN are miscible within certain copolymer composition ranges and exhibit lower critical solution temperature behaviour...
A novel type of catalysts useful in the anionic polymerization processes is demonstrated. Alkali metal ion pairs, e.g. K + crown ether, K - discovered first by Dye and Edwards were modified and used as catalysts in the polymerization of isoprene. The reaction mechanism including two-electron transfer to monomer and formation of a carbanion is discussed. The novel type of anionic polymerization...
This paper describes the dispersion polymerization of glycidyl methacrylate (GMA) employing poly(dimethylsiloxane) monomethacrylate as the stabilizer in supercritical carbon dioxide. Under the optimized conditions fine free flowing powder of discrete and cross-linked micropolymer particles are produced with high monomer conversion during a very short reaction time (<4h). The application of a power...
Dielectric techniques, including thermally stimulated depolarization currents and isothermal discharging currents measurements in addition to classical dielectric relaxation spectroscopy, were employed to investigate molecular mobility in the poly(imide-amide)-poly(ethylene adipate) (PIA-PEA) hybrid materials with short (M n =1.300gmol -1 ) PEA crosslinks. The techniques used...
The nanometer morphology of a mixture of the electrically conductive polymer poly(3,4-ethylenedioxythiophene) and polystyrenesulfonic acid is studied by means of solid state 13 C-CP/MAS NMR relaxation experiments. Based on the T 1 H and T 1ρ H NMR relaxation decay times, determined via the chemical shift selective carbon resonances, it can be concluded that the mixture...
This article describes the surface properties of fluorinated oxetane polyol (F-Polyol) containing linear segmented polyurethane elastomers. A series of polyurethane elastomers derived from a soft segment based on 2300g/mol polyhexamethylene carbonate, and a hard segment composed of 4,4'-methylene diphenyl diisocyanate chain extended with 1,4-butanediol were modified with a 3285g/mol F-Polyol via either...
Diffusion between a liquid polystyrene and a glassy poly(phenylene oxide) matrix is experimentally studied over a wide range of temperatures and diffusion times, using confocal Raman microspectroscopy. A specially designed experimental setup allows precise direct following of time evolution of the chemical composition profiles along the diffusion path. A direct and precise quantification is made for...
Crystallization experiments after shear treatment were performed to study the effect of shear on the crystallization kinetics and morphology of polypropylene. Experiments performed with a polarized light microscope revealed an increase in the number of activated nuclei after shear treatment, and alignment of these nuclei along flow lines after long shearing times. A crystallization half time was defined...
The role of each blend component on blend morphology and melt rheological properties was investigated for multicomponent compatibilized blends of polyamide 6 (PA6) and acrylonitrile-butadiene-styrene terpolymer (ABS). Blends with PA6 content of 50wt% were prepared at similar processing conditions on a ZSK 30 twin screw extruder. PA6/styrene-acrylonitrile co-polymer (SAN) blends showed a dispersed...
Novel high molecular weight poly(ethylene oxide)-b-poly(alkylglycidyl ether) diblock copolymers have been synthesized by sequential anionic-coordination polymerization using a calcium amide-alkoxide initiating system. The hydrophobic blocks were formed by polymerization of alkylglycidyl ethers differing in the size of the hydrophobe and the length of the oxyethylene spacer between the terminal hydrophobes...
The curing of a homogeneous mixture of a nematic liquid crystal and an acrylate UV curable prepolymer was studied by small angle light scattering, varying temperature and UV intensity. For all the conditions except at elevated temperature, the phase separation occurs with a spinodal decomposition which phases can be more or less easily recognised. Whatever the temperature below the clearing point...
The melting crystallization behavior of narrow-disperse polyethylene sample prepared from alkane solutions was studied by using differential scanning calorimetry. Avrami analysis of isothermal crystallization of these samples indicates that the PE sample prepared from n-octadecane has significantly higher crystallization rate than that from n-octane.
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