Showing papers in "Polymer in 1990"

TL;DR: In this article, a general guide to polymer miscibility is presented, which is based on a simple balance between unfavourable physical forces, described in terms of non-hydrogen bonded solubility parameters, and favorable specific interactions.

TL;DR: In this paper, the diffraction pattern of a polymer with a high degree of crystalline order was fitted with easily resolvable crystalline peaks, and the intensity not attributable to the crystalline peak was regarded as amorphous scattering.

TL;DR: Aqueous solutions of quaternized poly(2-vinylpyridine were investigated by static (SLS) and dynamic (DLS) light scattering over a wide range of polyelectrolyte, c pe, and salt concentrations in this article.

TL;DR: In this article, the phase separation of aqueous solutions of poly-(N-isopropylacrylamide) (PNIPAM) was investigated by fluorescence experiments that probe transfer of electronic excitation between donor and acceptor chromophores attached to the same polymer chain.

TL;DR: In this article, the properties of polymer liquid crystals (PLCs) and their dielectric properties are discussed, including their properties related to present as well as potential applications of liquid-crystalline and rigid rod materials.

TL;DR: In this article, the authors measured dissolved oxygen permeability, water content, crystalline structure, crystallinity, and density of silk fibroin membrane as a function of immersion time of the membrane in 50 vol% aqueous methanol solution.

TL;DR: In this article, an improved formulation for the nucleation rate j of a generalized sequential process is presented, where activation energy for chain sliding diffusion within crystals is introduced, and the topological nature of linear chains is formulated by introducing activation energy.

TL;DR: In this article, the authors examined the properties of chitosan derivative membranes for aqueous ethanol solutions and found that the evapomeation method was better than the pervaporation method for the permeation and separation characteristics.

TL;DR: In this article, the authors examined the general validity and applicability of their newly proposed alternative interchain packing and unit cell for syndiotactic polypropylene, in relation to the long-standing original structural model.

TL;DR: In this article, a chemical polymerization of 4,4′-dialkyl-2,2′-bithiophenes is reported, where the resulting soluble polymers can be cast from their chloroform solutions to give thin layers and free-standing films, which can be doped by electrochemical and chemical methods.

TL;DR: Grafting of poly(methyl methacrylate) (PMMA) on microparticulate silica was achieved by initiating the polymerization of MMA by 4,4′-azobis(4-cyanopentanoic acid) that was covalently bound to the silica surface.

TL;DR: In this article, low-molecular weight copolymers of l -lactic acid (LA) and ǫ-caprolactone (CL) were synthesized by direct copolycondensation without catalysts at 200°C under a nitrogen atmosphere.

TL;DR: In this article, it was found that as high as 80% of pendant double bonds are consumed immediately on polymerization and are wasted in primary cyclization, which is responsible for the delay in the onset of gelation at low mole fractions of divinyl monomer.

TL;DR: In this article, residual stresses arising from the curing process in a 3D-constrained epoxy resin were determined experimentally by a strain-gauge method using the theory of incremental elasticity for an ageing, linear thermoelastic material subjected to dimensional constraints.

TL;DR: Radical concentration histories for the bulk free radical copolymerization of methyl methacrylate (MMA) and ethylene glycol dimethacrylated (EGDMA) initiated with 0.3 wt% 2,2'-azobis(2-methyl-propionitrile) (AIBN) at 70°C over the entire composition range were measured with an on-line electron spin resonance spectrometer as discussed by the authors.

TL;DR: In this article, the mechanical properties and the swelling behaviour of hydrogels based on sodium carmelcellulose and hydroxyethyl cellulose were investigated, and it was shown that the cellulosic gels are superior to the acrylic polyelectrolytes currently in use for superabsorbent products.

TL;DR: In this article, the authors describe the preparation of colloidal dispersions of polypyrrole in aqueous media via a dispersion polymerization route, where particle aggregation is prevented by a steric stabilization mechanism due to the adsorption of a tailor-made poly(2-vinyl pyridine-co-butyl methacrylate) (P2VP-BM) random copolymer onto the sub-micrometre poly pyrrole nuclei.

TL;DR: In this paper, a mean-field theory describing the detailed structure and properties of planar grafted layers, formed by chains of two molecular weights, is developed, and several conclusions are drawn on the structure of grafted layer with arbitrary character of polydispersity of molecular weight.

TL;DR: In this paper, the authors used model epoxy network glasses to study the physical ageing response at different magnitudes of applied load, for different duration times of the load application and at different temperatures.

TL;DR: In this paper, three polyarylenevinylenes, poly( p -phenylenevinylene), poly(2,5-dimethoxy-p-phenylene-vinylene) and poly( 2.5-thienylene-polyvinylene), were prepared through new precursor polymers that were soluble in organic solvents and were chemically stable in air below 100°C.

TL;DR: In this article, high-molecular-weight copolymers of l -lactide and glycolide have been synthesized and the influence of the glycolides content on the mechanical and thermal properties of the as-polymerized copolymer was studied.

TL;DR: In this article, the Flory-Huggins χ parameter for a series of crosslinked rubbers swollen in an excess of different solvents was calculated using the Freed and Pesci lattice model.

TL;DR: In this paper, it was shown that the glass transition temperature Tg of a completely polymerized system is considerably higher than the temperature of polymerization, the reaction usually stops before completion.

TL;DR: The pH-dependent change of the pore size of poly(acrylic acid)-grafted, straight pored polycarbonate membrane was investigated in this article, where peroxide groups were generated on the surface of the poly carbonate membrane by glow discharge, and the membrane was heated in aqueous solution of acrylic acid to initiate the graft copolymerization.

TL;DR: In this paper, a polypropylene-maleic anhydride (PP-MA) copolymer was prepared by the solid phase graft copolymersization process, and the grafted polymer was analyzed by Fourier transform infrared spectroscopy, wet chemical methods, solid state 13C n.m.r.

TL;DR: In this article, the 13 C nuclear magnetic resonance (n.m.r.) spectrum and size exclusion chromatogram of the degraded copolymers of ethylene with α-olefins was used to determine the probability of branch inclusion.

TL;DR: In this paper, the authors used dynamic mechanical analysis to detect the presence of interzones existing between the polybutylene terephthalate (PBT) matrix and the EPR random copolymer.

TL;DR: In this paper, N-vinyl-2-pyrrolidone with methyl methacrylate was copolymerized to high conversion in both the presence and absence of ethyleneglycol dimethacrylated.