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Showing papers in "Polymer in 1970"


Journal ArticleDOI
01 May 1970-Polymer
TL;DR: The nucleating surfaces of polyolefins are rather low energy surfaces and the nucleating agents are insoluble in the polymer melt and are probably always crystalline substances as discussed by the authors.

174 citations


Journal ArticleDOI
01 Feb 1970-Polymer
TL;DR: In this article, the synthesis of polymers with tertiary amino groups as structural units is discussed. But the synthesis is restricted to polymeric compounds with enamines as monomers, and results of practical interest were obtained by copolymerizing enamines with acrylonitrile.

139 citations


Journal ArticleDOI
01 Jun 1970-Polymer
TL;DR: In this paper, it was shown that the nucleation density is highly dependent on the temperature of crystallization, and the density increases roughly by a factor of 10 at an increase in the degree of supercooling of 4°C.

133 citations


Journal ArticleDOI
G.A. Pogany1
01 Feb 1970-Polymer
TL;DR: In this article, a torsion pendulum has been employed to investigate the low temperature relaxation in epoxy resins and in certain related rigid polymers, such as polycarbonate, polysulfone, polyimide, polyphenylene oxide, Bakelite, and a Friedel-Crafts polymer.

96 citations



Journal ArticleDOI
01 Sep 1970-Polymer
TL;DR: In this paper, the molar cyclization equilibrium constants for cyclics [R(CH3)SiO]x have been measured in some undiluted and solution equilibrates with an accuracy of ±10%.

73 citations


Journal ArticleDOI
01 Feb 1970-Polymer
TL;DR: In this article, a method for predicting the glass transition temperature of polymers from the chemical structure was proposed, which uses increments for constitutional molecule groups and the found increments appear to correlate with the increments to the molar cohesion energy.

60 citations


Journal ArticleDOI
01 Mar 1970-Polymer
TL;DR: In this paper, a poly-N-vinyl carbazole, polymerized by free radical initiation, was fractionated and the fractions were characterized by gel permeation chromatography, viscometry, light scattering and osmometry.

52 citations


Journal ArticleDOI
01 Jan 1970-Polymer
TL;DR: In this article, the effect of substituent R on the thermal properties of three partially crystalline phosphazene polymers is investigated. But the results were limited to the case of CH 2 CF 3, C 6 H 4, and C 6H 5.

51 citations


Journal ArticleDOI
01 Jan 1970-Polymer
TL;DR: In this paper, the reaction between ammonium chloride and phosphorus pentachloride was found to give polymers of intrinsic viscosity ≤ 0.66 dl/g.

37 citations


Journal ArticleDOI
01 Sep 1970-Polymer
TL;DR: In this paper, natural rubber samples were vulcanized in the presence of n-decane, decalin and o-chlorobenzene and the diluents were then removed, and the force-extension characteristics of the samples studied over the range 1·1

Journal ArticleDOI
01 May 1970-Polymer
TL;DR: In this paper, a statistical treatment of phase separation in three-block copolymers (styrene-butadiene-styrene) is given; the formation of polystyrene islands is favored by surface energy terms and opposed by entropic terms.

Journal ArticleDOI
01 May 1970-Polymer
TL;DR: In this article, a simple treatment of chain entanglement based on probability theory leads to a more general equation of the form ν o =a o +a 1 M w +a 2 M w 3 +a 3 M w 5......

Journal ArticleDOI
01 Aug 1970-Polymer
TL;DR: In this article, the authors have shown that polyethylene is endothermic for all the gases except CO2 and in Nylon 11 for all except Ar and CO2.

Journal ArticleDOI
01 Jan 1970-Polymer
TL;DR: In this paper, an apparatus has been devised to measure the stress/temperature coefficients of elastomers in torsion, and the experiments carried out enable the temperature coefficient of the mean-square chain vector length r 0 2 to be derived.


Journal ArticleDOI
01 May 1970-Polymer
TL;DR: In this paper, the nuclear magnetic resonance peaks of the α-carbon protons of different synthetic polypeptide samples show differences in behaviour as the material is taken through a helix-coil transition; these differences have hitherto been ascribed to variations in helix coil interconversion rates.

Journal ArticleDOI
01 Dec 1970-Polymer
TL;DR: In this paper, the x-ray diffraction method of correlation crystallinity index was used to measure the relative crystallinity of fibres of cellulose triacetate yarn heat treated in the range 20-300°C.

Journal ArticleDOI
01 Sep 1970-Polymer
TL;DR: In this paper, the authors used rotational isomeric state models to describe the conformational statistics of the corresponding linear chains and calculated the equilibrium concentration of cyclic trimer in poly(ethylene terephthalate) (pet ) melts by the Jacobson and Stockmayer theory.

Journal ArticleDOI
01 Apr 1970-Polymer
TL;DR: In this article, a differential scanning calorimeter has been used to measure the heat capacities of nylon-6 samples, which had been subjected to different doses (0-1000 Mrads) of cobalt-60 gamma radiation at 298°K, over the temperature range 200-550°K.

Journal ArticleDOI
01 Dec 1970-Polymer
TL;DR: In this article, the peroxy radicals of polytetrafluoroethylene ( ptfe) were investigated in detail and the results were quantitatively analyzed based on Kneubuhl's theory on the line shape.

Journal ArticleDOI
01 Jul 1970-Polymer
TL;DR: In this article, a study of the thermodynamic properties of concentrated solutions of tactic poly(∝-olefins, prepared by means of Ziegler-Natta catalysts, and analyzed in terms of various theories of polymer solutions is presented.


Journal ArticleDOI
01 Aug 1970-Polymer
TL;DR: The transesterification reaction in the melt of 4,4-dihydroxy-diphenyl-2,2-propane with diphenyl carbonate proceeds in a homogenous system without anomalous phenomena above 230°C as mentioned in this paper.

Journal ArticleDOI
01 Mar 1970-Polymer
TL;DR: In this article, the properties of polyethylene are investigated as functions of annealing temperature, including density, tensile modulus, and solvent swelling, and the properties converge on those values appropriate to bulk polymer as the annesaling temperature approaches the melting point, but this convergence is not monotonic.

Journal ArticleDOI
01 Apr 1970-Polymer
TL;DR: In this article, a differential scanning calorimeter has been used to measure the heat capacities of polyethylene single crystals and melt crystallized samples of isotactic polypropylene, which had been subjected to different doses (0.1000 Mrads) of cobalt-60 gamma radiation at 298°K and 425°K, respectively.

Journal ArticleDOI
01 Jul 1970-Polymer
TL;DR: In this article, an apparatus for measuring the Doppler effect in the light scattered by solutions of macromolecules is described, and the spectral broadening is measured by means of an optical homodyne technique, the theory of which is discussed together with practical considerations involved in its application.

Journal ArticleDOI
01 Apr 1970-Polymer
TL;DR: In this article, the glass transition temperatures (Tg) of a series of high molecular weight aromatic polyimides were measured by differential scanning calorimetry at heating rates of 8-64°K/min on samples of controlled thermal history, and Tgs at a dilatometric heating rate (0.06°k/min) were estimated.

Journal ArticleDOI
01 Apr 1970-Polymer
TL;DR: The effects of small doses of gamma radiation on linear and branched poly(vinyl acetate) were investigated in this paper, where the linear polymer increases in molecular weight with dose as expected for a random cross-linking process.

Journal ArticleDOI
01 Nov 1970-Polymer
TL;DR: In this paper, the authors compared the stress/strain curves under biaxial tension with simple tension test results for cellulose nitrate and abs sheet and obtained an approximate correlation using criteria of true stress or maximum shear stress and maximum tensile strain.