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Certain styrene/maleic anhydride copolymers (SMA) are completely miscible with poly(methyl methacrylate) (PMMA). This paper explores the solubilization of SMA copolymers in the grafted PMMA shell layer of emulsion-made core-shell impact modifiers by examining glass transition behaviour and morphology of SMA/core-shell modifier blends. There appears to be a single, composition-dependent hard phase...
Electron beam initiated crosslinking of ethylene vinyl acetate (EVA), containing 12% vinyl acetate with trimethylolpropane trimethacrylate (TMPTMA), has been carried out over a range of radiation doses (2-20 Mrad) and concentrations of TMPTMA (0.5 to 5 parts by weight). The residual concentration of carbonyl groups due to oxidation and incorporation of TMPTMA into the crosslinked EVA, as determined...
The present study reveals that the observed variation of thermal conductivity λ with temperature, for any non-conducting linear amorphous polymer can be explained by considering phonons as chief heat carriers. It is proposed that in the temperature region below the glass transition temperature, T g , structure scattering and chain-defect scattering are the predominant phonon scattering processes,...
Drawn polypropylene fibres were produced from as-spun fibres with a paracrystalline structure of low orientation. Drawing was carried out at 60 o C in order to prevent the transformation of the paracrystalline form into the monoclinic structure. The internal texture of the as-spun fibre and of a series of drawn fibres has been investigated by electron microscopy following permanganic etching...
Polystyrene microspheres ranging in diameter from 3 to 10 μm were prepared in alcoholic media by dispersion polymerization of styrene in the presence of a methacrylic acid/ethyl acrylate 1:1 statistical copolymer (Eudragit) as the stabilizer precursor. The effects of the initial Eudragit and free radical initiator concentrations on the microsphere dimensions, the microsphere size distribution and...
Nylon 66 copolymers were prepared by melt polycondensation of nylon 66 salt with 10-30 mol% (in feed) of 1,3-propanediol and 2,2-dialkyl-1,3-propanediols, where the alkyl groups are dimethyl, diethyl and butyl-ethyl. Reduced specific viscosity was decreased by the copolymerization. Comonomer contents in copolymers were considerably smaller than those in the feed. Crystallinities and densities of...
Poly(2-vinylpyridine-g-styrene)s were prepared by successive coupling reactions of polystyryl anion and poly-2-vinylpyridinyl anion prepared by anionic polymerizations, with trifunctional coupling agent, tris-bromomethylbenzene. Five samples were prepared and characterized. Their volume fractions of polystyrene graft, o s , were determined to be 0.24, 0.34, 0.45, 0.58 and 0.67, respectively...
The self-diffusion coefficient distribution, obtained from an inverse Laplace transform of the pulsed-gradient spin-echo nuclear magnetic resonance attenuation function, has been studied as a function of both associative polymer and surfactant concentration. Compared to the parent homopolymer, the associative polymer exhibited a much wider distribution of self-diffusion coefficients, which narrows...
The 13 C nuclear magnetic resonance (n.m.r.) spectra were found to provide a means for direct observation of the structures formed along the glycolide/lactide copolymer chain upon transesterification. Nevertheless 1 H n.m.r. spectroscopy appeared to be more convenient and useful in the analysis of chain microstructure. The glycolide methylene group region of the proton spectra...
Plasma polymerization reactions and plasma polymers of xylene/air, xylene/argon, xylene/air/argon, toluene/air/argon, dioxane and allyl cyanide were compared with respect to discharge power (between 50 and 500 W), where all other plasma operational parameters were kept constant. In plasma polymerization, the glow characteristics are known to play an important role depending on the factor W/F, where...
An unsaturated polyester resin was cured with different catalyst contents. The crosslinking process was followed by static and dynamic viscosimetry and by differential scanning calorimetry (d.s.c.). Activation energies were determined from the gel times obtained by viscosimetry and from the variation in the maximum exotherm temperature obtained by d.s.c. at different heating rates. The existence...
A thermoplastic elastomer (TPE) prepared by mechanical blending of nitrile rubber (NBR) and poly(vinyl chloride) (PVC) was investigated by solid-state 13 C nuclear magnetic resonance (n.m.r.) spectroscopy with cross-polarization/magic-angle spinning (CP/MAS). The CP/MAS 13 C n.m.r. measurements of T 1H andT 1ρH relaxation times for the TPE...
A reflectance Fourier transform infra-red (FTi.r.)/differential scanning calorimetry (d.s.c.) microscopic system was used to investigate the reaction rate and reaction order of anhydride formation in Eudragit L-100 film by isothermal stability study. The accelerated stability testing was performed at 160, 180, 190 and 200 o C for 3 h. The changes in three-dimensional reflectance FTi.r. spectra...
Some new attempts to demonstrate the superiority of the GTTG - conformation of isotactic triads relative to other labile structures containing allylic or tertiary chlorine in inducing the thermal degradation of poly(vinyl chloride) (PVC) are presented. They concern: (i) the degradation of polymers after nucleophilic substitution in two types of solvent involving the removal of the GTTG ...
Butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene and 4-methyl-1,3-pentadiene have been polymerized with MAO/Cp'VCl 2 . 2PEt 3 and MAO/Cp 2 VCl (Cp' = C 5 H 4 Me, Cp = C 5 H 5 ). Polymers, predominantlycis -1,4, have been obtained from butadiene and pentadiene, a polymer with a mixed cis/trans structure has been obtained from 2-methyl-1,3-pentadiene,...
In the copolymerization of styrene-butadiene and styrene-isoprene, a novel rare earth catalyst system (CF 3 CO 2 ) 3 Ln/R 3-n AlH n /(CH 3 ) 3 CCH 2 Br (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; R = Me-, Et-, i-Bu-, and Oct-; n = 0 and 1) has been studied. The 1,4 unit contents in the copolymers obtained...
The gas transport properties for H 2 , O 2 and N 2 in five random copolymers of polypyrrolone and polyphenylquinoxaline and the two homopolymers have been determined at 30 o C and 1 atm. The polypyrrolone exhibits higher selectivity with lower permeability, whereas polyphenylquinoxaline shows lower selectivity with higher permeability. The permeability of the copolymers...
The oxidative polymerization of aniline gives rise to polyaniline which exists in a variety of forms, differing in electrical conductivity and in colour. A scheme of interrelated structures which accounts for all the spectroscopic and conductometric observations, is proposed, together with a set of equations summarizing the chemical transformations involved.
A new method has been developed that uses model u.v./visible absorption spectra to determine the relative resonance enhancement factors and the ranges of polyene lengths that contribute to a particular resonance Raman spectrum from a thermally degraded poly(urethane) foam-backed poly(vinyl chloride) sheet. Resonance Raman spectra were recorded using Microline Focus instrumentation with 514.5, 488...
The copolymerization of dimethyl itaconate and methyl methacrylate with 2,2'-azobisisobutyronitrile was investigated kinetically at 50 o C in benzene. The copolymer composition conforms to the terminal model within experimental error, but the variation of the copolymerization rate shows a penultimate effect on the propagation reaction. Homopolymerization kinetic coefficients for dimethyl...
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