Showing papers in "Polymer in 1980"

TL;DR: In this paper, the effects of polymer concentration on chain dimensions in good solvents are discussed in order to define the boundary between the semi-dilute and concentrated regimes, and it appears that chain dimensions should approach their unperturbed values for many systems at polymer volume fractions in the range of 0.05-0.20, independent of molecular weight.

TL;DR: In this paper, a study has been made of the general crystallization behavior of poly(L-lactic acid), PLLA, and is intended to be the basis for further work on fibre formation processes.

TL;DR: In this article, the photochemical and thermal cis-trans isomerization of azo chromophores which were either dissolved, a pendant group or part of a crosslink in rubbery poly(ethyl acrylate) networks has been investigated.

TL;DR: In this paper, case II diffusion in glassy polymers is considered in terms of a deformation model, where the process is controlled by the mechanical response of the glass just ahead of the sharp front to an osmostic swelling stress.

TL;DR: In this article, the mechanism for crystal transformation in poly(vinylidene fluoride) by a tensile deformation at atmospheric pressure was investigated in the temperature range 25-150 °C.

TL;DR: In this paper, a discharge-treated polyethylene terephthalate (PET) film has been discharge-treated under controlled conditions and the resulting surface modifications analysed via Xps (ESCA), contact angle and surface energy measurements changes in surface properties have been followed as a function of ageing time.

TL;DR: In this paper, a new method has been proposed for the interpretation of the dynamic scattering experiments in terms of the initial slope,,Q, of In S(q, t).

TL;DR: In this paper, the tensile deformation of poly(p -phenylene terephthalamide) fibres has been investigated using a series model consisting of a linear arrangement of crystallites and the deformation is largely brought about by the elastic strain and irreversible rotation of the crystallites.

TL;DR: In this article, the influence of the temperature on the drawing behavior of gel-fibres, which were obtained by spinning of a 2% w/w solution of high molecular weight polyethylene (M w = 1.1 × 10 6 ) in decalin, was studied in the range from 70 to 143°C.

TL;DR: In this paper, the three principal refractive indices of poly(ethylene terephthalate) were found to be 1.645, 1.573, and 1.541.

TL;DR: In this article, the cohesive energy density of Nafion has been determined experimentally from swelling measurements using the method of Britow and Watson, and the results show that there are two distinct swelling envelopes corresponding to dual cohesive energy densities: one is ascribed to the organic part of the membrane, whereas the other is tentatively attributed to ion clusters in the material.

TL;DR: In this article, the authors considered the problem of the swelling and collapse of a polymer network in a good solvent and showed that the network can collapse in a discrete first order phase transition (if the network chains are stiff or if it is stretched along one or two axes), or as a continuous non-phase transition (located in a narrow temperature range).

TL;DR: In this article, a planar-flow cross-slot device was used for the retraction of the molecules from full extension through birefringence observations and the relaxation time associated with this process was found to be considerably larger than that for the extension from the coiled state found in Part 1.

TL;DR: In this article, it was found by analysis of the composition and n.m.r. behavior of low-conversion soluble copolymers of styrene (S) with 5-60 wt% of ethylene dimethacrylate (EDMA) that cyclization strongly predominates in crosslinking copolymerization.

TL;DR: In this paper, the authors show that poly(vinylidene fluoride) spherulites of the α-phase undergo a transformation to the higher-melting γ-form when crystallized at high temperatures.

TL;DR: In this paper, the absorption of liquids by polymers which contain liquid-soluble inclusions is described, and it is shown that the equilibrium uptake of liquid can be calculated if several properties of the inclusion such as solubility as well as the modulus of the polymer are known.

TL;DR: In this article, the effect of high-dose radiation on the paraffinoid crystal lattice is investigated. But the main finding is not the occurrence of an orthorhombic-hexagonal phase transition on heating subsequent to irradiation at ambient temperature beyond a certain critical dose.

TL;DR: In this article, a series of polymethacrylates from poly(methyl methacrylate) to poly(n-hexyl methyl ketone) were found to be compatible with PVC.

TL;DR: In this article, the photocontractile effect observed on switching off the radiation is attributed to incomplete isomerization of a fraction of the azo residues in locations within the polymer matrix.

TL;DR: In this article, a study was carried out to investigate molecular orientation in injection moulded bars of short glass fibre reinforced polypropylene and polyethylene and found that the fibres do not appear to have any direct effect on the matrix orientation.

TL;DR: In this paper, a computerized infra-red study was carried out on blends of poly(vinylidene fluoride) (PVF2) with isotactic or syndiotactic poly(methyl methacrylate) (it- and st-PMMA) to investigate the effect of tacticity of PMMA on the interaction with PVF2.

TL;DR: In this article, the mechanism of physical aging in isotactic polypropylene was studied in the α-region (15-80°C) by thermally stimulated creep and by creep superposition.

TL;DR: In this article, the authors investigated the nature of chain extension of high-molecular weight atactic polystyrene in an elongational flow field and studied the sudden onset of high extension which, according to theory, is governed by the expression ϵ c τ = 1.

TL;DR: In this article, the rubber phase volume fraction (RPVF) was used as a variable in the synthesis of impact polystyrene and it was found that notched Izod impact strength increased linearly with RPVF, while tensile yield strength was inversely proportional.

TL;DR: In this article, the reactivity of low-molecular weight polybutadiene (1,2-PB) and n-butyllithium (1-4-PB), and the effect of epoxy groups formed on the polymer solution viscosity has been investigated.

TL;DR: The phase diagram of polytetrafluoroethylene is enlarged by differential scanning calorimetry to include the concentration of hexafluoropropylene comonomer units.