Polymer
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Near u.v. light induced graft copolymerizations of water-soluble monomers such as acrylamide, acrylic acid, the sodium salt of 4-styrenesulfonic acid and N,N-dimethylaminoethyl methacrylate onto pristine and Ar plasma pretreated film surfaces of high-density polyethylene, poly(ethylene terephthalate) and polystyrene were carried out. Using angle-resolved X-ray photoelectron spectroscopy (XPS), the...
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The miscibility of poly(p-vinylphenol) (PVPh) with several poly(dialkyl itaconate)s and poly(methoxy-carbonylmethyl methacrylate) (PMOCMA) was studied by d.s.c. and Fourier transform infra-red (FTi.r.) spectroscopy. Poly(dimethyl itaconate) and a low molecular weight poly(diethyl itaconate) are miscible with four PVPh samples with molecular weights ranging from 1.7 to 30 kg mol −1 . A high...
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End-functionalized hydroxyethyl methacrylate macromonomers of poly(l-lactide) (HEMA-PLA) were synthesized by the ring-opening polymerization of l-lactide (LA), using mono- and trihydroxyethyl methacrylate-aluminium alkoxides as initiators. The polymerization carried out in toluene at high vacuum and 60°C presented a living character, giving rise to the formation of a linear polymer without cyclization...
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Acrylic monomers were grafted on the surface of commercial polyamide membranes using plasma polymerization and ultraviolet irradiation techniques. Graft reaction was confirmed by X-ray photoelectron spectra. Grafting yield increased with plasma and ultraviolet exposure time. Permeation of riboflavin through graft membranes was investigated. Poly(acrylic acid-g-amide) membranes showed a decrease in...
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To study the plastic deformation of polymer crystals, the structure and molecular motion in surface-constrained polymethylene crystals containing 192 C 50 H 100 chains were followed using molecular dynamics simulations. Total energy, temperature and density were evaluated as a function of time up to 100 ps. Structure changes, longitudinal and transverse mass transport, changes in setting...
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The phase-separation process of a rubber-modified epoxy system during curing was described in terms of a nucleation-growth mechanism. It was derived from morphological observations that spherical domains were developed during polymerization in a continuous matrix. The morphological changes were recorded in real time by means of optical microscopy. We have applied a model to predict the amount and...
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The formation of a reversible gel by complexation of borate ions with poly(vinyl alcohol) is described. The complexation induces electrostatic charges on the polymeric chains. We focus on the behaviour of the system when the charges are partially screened by a passive salt. In such a case, ‘re-entrant phases’ can be observed; they result from a delicate balance between the electrostatic repulsions...
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Phenylphosphine oxide-containing poly(arylene ether imide)s, poly(arylene ether quinoxaline)s, poly(arylene ether benzoxazole)s and poly(arylene ether benzothiazole)s were prepared by reacting the appropriate difluoro heterocyclic compound with bis(4-hydroxyphenoxy-4′-phenyl)phenylphosphine oxide. The polymers exhibited glass transition temperatures from 209 to 255°C and inherent viscosities from...
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The synthesis of a polyamide entirely based on naturally occuring compounds has been carried out by polycondensation of N,N-bis(trimethylsilyl) l-lysine ethyl ester and bis(pentachlorophenyl) di-O-methyl-l-tartrate in a chloroform solution. The new polytartaramide has a molecular weight of ∼6000, displays high optical activity and is soluble in water. The regioregularity of the polymer has been examined...
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Morphological features of melt crystallized cis-1,4-polybutadiene were examined by means of polarized light microscopy. Samples similar in branching characteristics but different in molecular weight (MW) were studied. High MW samples exhibited features of dwarf spherulites. Samples of lower MW formed spherulites of radial texture at low crystallization temperatures (T c ), spherulites of banded...
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A thermoset/thermoplastic blend, triglycidyl p-aminophenol (epoxy)/poly(ether sulfone) (PES) was cured using the curing agent 4,4′-diaminodiphenylsulfone, and the structure formation during cure was investigated by time-resolved light scattering. After a certain time lag, the scattering peak appeared and its intensity increased with cure time, suggesting the development of reaction-induced spinodal...
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13 C n.m.r. spectroscopy was used to differentiate between block and statistical copolymers of hydroxy-methylthiirane and methylthiirane. Block copolymers could be exclusively obtained if hydroxymethylthiirane constituted the first sequence; however, if the first sequence consisted of methylthiirane, the synthesis of block copolymers failed because of a termination reaction. We demonstrate that...
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Low-molecular-weight di-end-functional (telechelic) telomers were prepared by radical addition-substitution-fragmentation transfer reactions on ethyl 2-[1-(1-methoxy-1-cyclohexylperoxy)ethyl]propenoate (EMCPEP), used as a new chain-transfer regulator in the free-radical polymerization of methyl methacrylate (MMA), styrene (St) and butyl acrylate (BA). The chain-transfer constant obtained in MMA polymerization...
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The structure and morphology of nylon 8 chain-folded lamellar crystals have been studied using transmission electron microscopy including selected area electron diffraction. Solution grown lamellar crystals are lathe-like in appearance. Two types of diffraction pattern have been indentified, indicating two crystal forms. The normal room temperature form is monoclinic with a = 0.964nm, b = 0.803nm,...
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Structurally altered high density polyethylene pipes were produced by flow-forming, a point rotary cold rolling process. The process was performed by using three rollers on a conventional lathe machine. The variation of mechanical and pressure rupture properties (tensile strength, yield strain, toughness and hoop stress) with percentage reduction was studied. The stress-strain behaviour of the flow-formed...
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Poly(2-methoxy-5-(2-(4-nitrophenyl)ethenyl)-1,4-phenylenevinylene) (PMNEPV) and a series of copolymers (poly(MNEPV-co-PV)) containing varying amounts of 1,4-phenylenevinylene (PV) units have been synthesized via soluble precursor polyelectrolytes. These polymers possess a unique structural feature in which the electron-donating methoxy groups are located on the phenylene rings along the main chain...
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The steady shear viscosities of two microphase-separated triblock copolymers, a polystyrene-block-polybutadiene-block-polystyrene copolymer (Kraton 1102) and a polystyrene-block-polyisoprene-block-polystyrene copolymer (Kraton 1107), were measured at various temperatures, using a cone-and-plate rheometer at low shear rates (ca. 0.01–10s −1 ) and a capillary rheometer at high shear rates (ca...
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Pullulan was selectively functionalized at its reducing terminus via reductive amination of the terminal aldehyde with 2-(4-nitrophenyl)ethylamine. The nitro group serves as a precursor for an amino group which can be converted into a reactive isothiocyanate group. The latter can be coupled with amines.
