Showing papers in "Polymer in 1983"

TL;DR: The morphology and related properties for the aromatic thermoplastic poly(aryl-ether-etherketone) (PEEK) [C6H4O C6H 4 O OC 6H4-CO]n were described in this article, including crystallinity, crystallization and melting behaviour, Iamellar thickness and spherulitic structure.

TL;DR: In this article, the microstructure and fracture behavior of an unmodified and a rubber-modified epoxy have been studied and the mechanisms for this increased toughness have been considered and a mechanism that accounts for all the observed characteristics has been proposed.

TL;DR: In this article, the authors extended the kinetic nucleation theory of chain folding, including the effects of reptation, to predict the increase in crystal growth rate G that is implied by measurements on PE and POM at moderately large undercoolings.

TL;DR: In this paper, the phase separation of dissolved polyethersulphone (PES) from trifunctional and tetrafunctional epoxy resins during curing was studied using electron microscopy and dynamic mechanical spectroscopy.

TL;DR: In this article, the morphology and crystal growth of poly( l -lactic acid), PLLA have been studied from the melt as a function of undercooling and molecular weight using hot stage microscopy.

TL;DR: In this article, a qualitative mechanism involving cavitation, shear yielding and plastic flow was proposed to calculate values of the crack opening displacement and the correlations established between stress intensity factor, KIc, yield stress and type of crack growth suggest that the extent of crack tip blunting largely governs the relative toughness of the epoxy materials.

TL;DR: In this article, the structural, chemical and polymeric properties of gelatin are discussed with respect to the structural transformations, physico-mechanical and chemical properties, internal stress and relaxation properties.

TL;DR: In this article, the effects of uniaxial drawing or poling on the structural changes involved in the ferroelectric-to-paraelectric phase transition in copolymers of vinylidene fluoride and trifluoroethylene were examined and compared to the behaviour of as-crystallized films.

TL;DR: In this paper, the 13C{1H} n.m. spectra of a series of poly(lactic acid) stereocopolymers obtained by different means, i.e., ring-opening polymerization of l -, rac- and meso-lactides initiated by powdered Zn, or copolymerization of L - and rac- lactides in different proportions, or condensation polymerisation of rac lactic acid.

TL;DR: In this article, the role of amorphous entangled tie molecules in preventing slow crack-type fracture in polyethylene pipe is described, and relative resistance to slow crack brittle failure is explained in terms of this model for various materials tested.

TL;DR: In this paper, two exothermic peaks of crystallization of water sorbed on polyhydroxystyrene were observed, one was a sharp peak (Peak I) observed at about 255 K in a d.s.c. curve; the other was a small broad peak (peak II) observed by using differential scanning calorimetry.

TL;DR: In this paper, an efficient synthetic route to pure, high molecular weight poly(p-hydroxystyrene) is reported, which involves synthesis of a new monomer, p-tert-butoxycarbonyloxystyrene, polymerization by radical initiation or by cationic initiation in liquid SO2, followed by thermolysis or acidolysis of the tertbutoxy carbonyl protecting group.

TL;DR: In this paper, differential scanning calorimetry (d.s.c.) data on non-isothermal crystallization of isotactic polypropylene and high-density polyethylene from the melt at different cooling rates were treated in terms of the Ozawa equation.

TL;DR: In this article, the formation, melting and phase transition of isotactic polybutene-1 under high hydrostatic pressures were studied by high-pressure d.t.a. and X-ray diffraction up to 5 kbar.

TL;DR: In this paper, the authors investigated the phenomenon of slow stable crack growth in polyethylene using notched specimens subject to constant load and the concepts of fracture mechanics and demonstrated that Kc is the controlling stress parameter for crack growth under suitable conditions.

TL;DR: In this paper, Fourier transform infra-red (FTi.r) studies of the polymer blend system poly(hydroxy ether of bisphenol A) (phenoxy)-poly(e-caprolactone) (PCL) are presented.

TL;DR: In this article, the effect of γ-irradiation on poly(lactic acid), PLA, synthesized by the solution polymerization of lactic acid in air and N2 atmosphere, was studied.

TL;DR: Functionalized polymers have continued to find increasing use as supports for reagents, catalysts and protecting groups as mentioned in this paper, along with the use of polymeric species in metal ion separations, in racemate resolutions, as specific adsorbents, in organic synthesis (notably in asymmetric reactions) and in the trapping and identification of reactive intermediates.

TL;DR: In this article, the influence of thermal history on the structure of gelatin gels has been investigated by measuring the specific optical rotation [α ] λ at λ = 436 nm, and the helix content χ in the gels was derived by reference to the native collagen.

TL;DR: In this paper, a series of random copolymers were produced containing epoxy co-units on the main chain of a cis 1,4 polyisoprene polyamide.

TL;DR: In this paper, the structure of liquid crystalline copolyesters prepared from 4-hydroxybenzoic acid (HBA) and 2hydroxy-6-naphthoic acid(HNA) was investigated using X-ray data.

TL;DR: In this paper, the growth faces of polyethylene are analysed in terms of a roughness which, on the {110} faces, increases progressively over a temperature range of about 100°C.

TL;DR: In this paper, drawn fibres and shear-oriented thin films of four thermotropic liquid crystalline polymers have been examined using polarized light optical microscopy and transmission electron microscopy.

TL;DR: In this paper, a positive charge-injecting electrode for an electroluminescent device based on films of polyvinyl carbazole was proposed. But the results of the reaction produced a very different cation yield from that obtained by use of a carbazoles dimer and reasons for this, associated with dimerization of the monocarbazole groups, are suggested.

TL;DR: In this paper, self-diffusion coefficients were found to be proportional to M−2.0±0.1w above and below the critical molecular weight Mc. The influence of internal field gradients, which have previously been reported for polyethylene melts, is demonstrated and discussed.

TL;DR: In this article, branch structures were determined in fractions of a commercial suspension of PVC and experimental PVC samples obtained at subsaturation conditions (U-PVC) with 13 C n.m. spectroscopy at 50.31 MHz after reductive dehalogenation with tributyltinhydride.

TL;DR: In this article, the effect of high relative humidity on the efficiency of electrical discharge treatment for rendering polypropylene film printable has been re-examined and a consistent explanation of both effects based on the degree of surface coverage by physically adsorbed water is put forward, supported by X-ray photoelectron spectroscopy analysis of treated film surfaces.

TL;DR: The difference in swelling of polyacrylamide gels of various polymer concentrations and the nuclear magnetic resonance self-diffusion measurements of water in these gels suggest that inherent inhomogeneities in dilute gels play an important role in the thermodynamic and transport properties as discussed by the authors.

TL;DR: A series of random thermotropic poly(4-oxybenzoate-co-ethylene terephthalate), P(OB/ET), and poly(3-chloro-4-oxide-poly(poly(COB/ET)) copolymers were prepared and their thermal properties were determined.

TL;DR: In this article, the mesophases of the homologous series of polymers prepared from p,p′-bibenzoic acid and the tetra-, hexa-, octa-, and decamethylene glycols were studied.