Showing papers in "Polymer in 1981"

TL;DR: The degradation mechanism of polyglycolic/polylactic acid (PGA/PLA), homo and copolymers synthesized as in Part 11, has been studied in vitro as mentioned in this paper.

TL;DR: In this paper, Farnham et al. showed that copolytherketones and copolyaryletherketone-sulphones can be obtained by polycondensation of bis-4-halogenophenyl ketones with the potassium salt of 4-fluorophenyl 4-hydroxyphenyl ketone using certain diaryl sulphones as solvents for the reactions.

TL;DR: A formal solution to this problem is given using the replica formalism and the contribution of an entanglement to the free energy of shear is given by 12kT∑iλi 2(1+η)1 + ηλi2 + kT∩log(1-ηλ i2) where λi are the Cartesian extension ratios and η is a measure of the freedom of a link to slide compared with the freedom with thefreedom

TL;DR: In this paper, it was shown that the species dependence and the concentration dependence are related, and that to a first approximation both are manifestations of a universal law relating a mechanical interaction density, measured by G 0 N kT to the length of uncrossable chain contour per unit volume.

TL;DR: In this paper, the case II diffusion of penetrants in polymer sheet is associated with constrained swelling of the material and the generation of internal stresses, and it is shown that the specimen shape change, as the fronts meet, is also accompanied by an increase in the degree of solvent uptake as the hydrostatic stress component on the swollen layers is relaxed.

TL;DR: In this paper, the effects of mutual interactions between the chains of a molecular network are taken into account by a van der Waals approach for an ideal conformational gas, and the utility of the new equations of state can be judged by their ability to describe the results of a set of different known experiments.

TL;DR: In this paper, annealing-induced ordering in segmented elastomers has been studied and shown to be an intradomain phenomenon not associated with the interphase between domains, or necessarily dependent on the chain architecture of segmented Elastomers.

TL;DR: In this paper, a general formalism is developed to calculate the scattering intensity and is applied to special cases: diblock and triblock chains, and it is shown that even a small chemical polydispersity leads to important long-range fluctuations and modifies the scattering spectrum substantially.

TL;DR: Blends of poly(vinyl chloride), PVC, with the polyesters poly(butylene adipate), poly(hexamethylene sebacate, poly(2,2-dimethyl,1,3-propylene succinate) and poly(1,4-cyclohexanedimethanol succinate), were found to exhibit a single, composition dependent glass transition as mentioned in this paper.

TL;DR: In this paper, a structural mechanism describing the mode of deformation is proposed which is based on the initial formation of kink-bands, consistent with an observed loss in tensile strength after compression.

TL;DR: In this article, the creep and recovery behavior of ultra high modulus polyethylene has been studied over the temperature range 20 −70°C and four types of material were examined; low molecular weight and intermediate molecular weight homopolymer, an ethylene hexene-1 copolymer, and a sample prepared by γ-irradiation of isotropic low molecular-weight polymer prior to drawing.

TL;DR: In this article, an earlier relation describing swelling equilibria in polyelectrolyte networks is analyzed from the viewpoint of the effect of electrostatic interactions on the existence of phase transition in polyacrylamide gels.

TL;DR: In this paper, low density polyethylene was fluorinated in a glow discharge generated from a dilute mixture of fluorine in helium and the effects of pressure, flow rate, power and time of treatment have been examined.

TL;DR: In this article, the degradation mechanism of poly(ethylene oxide)/poly (ethylene terephthalate) (PEO/PET) copolymers, synthesized as described in Part 11, has been studied in vitro.

TL;DR: In this article, the local conformational structure of atactic PMMA has been derived from WAXS, and the underlying conformation is near to the all-trans energy minimum proposed by Sundararajan and Flory.

TL;DR: In this paper, it was shown that for a simple cubic lattice, the ratio of number of loops to the number of bridges in the amorphous run of a semicrystalline polymer is 2 3.

TL;DR: In this article, an electron diffraction pattern from polytetrafluoroethylene in Phase II was analyzed to determine a chain conformation of 2.1598 CF2 units per turn of the helix.

TL;DR: In this paper, Fourier transform infra-red (FT i.r.) studies of binary polymer blends containing polyvinyl chloride (PVC) and the polyesters, poly(α-methyl-α-n-propyl-β-propiolactone) and poly(δ-valerolactone), are presented.

TL;DR: In this article, two types of difunctional organolithium initiators have been prepared by addition of sec or tert-butyl lithium on two families of non-polymerizable precursors having two nonconjugated double bonds.

TL;DR: In this paper, cyclic and linear poly(dimethyl siloxanes) were heated under vacuum in the temperature range 623-693K for periods of hours or days in the absence of catalysts.

TL;DR: A series of poly(n-alkyl itaconic acid esters) with side chain lengths from 7 to 20 carbon atoms have been prepared and two glass transition temperatures have been detected as discussed by the authors.

TL;DR: In this article, a simple method for computing magnetic resonance line shapes by superposition of a relatively small number of subspectra, which can in turn be calculated analytically, is described.

TL;DR: Lower critical solubility temperatures (LCST) of linear polyethylene (PE), isotactic polypropylene (PP), and of five random EP copolymers of different composition have been measured in (i) five linear alkanes (n-C5 to n-C9); (ii) sixteen branched alkanes and (iii) four cycloalkanes as discussed by the authors.