Showing papers in "Polymer in 1973"

TL;DR: In this article, the molecular and crystal structure of naturally occurring optically active poly(β-hydroxy-butyrate) was analyzed by X-ray diffraction and it was shown that the racemic polymer has an isotactic configuration and consists of two kinds of crystallites.

TL;DR: In this paper, the dynamic-mechanical and thermal scanning behavior of a series of specially synthesized linear segmented polyurethanes is presented, and the results are explained in terms of hard segment domain perfection.

TL;DR: In this article, it was found that fibrous crystallization of polyethylene melt appeared to occur preferentially along this axis, implying that longitudinal velocity gradients played an important part in the production of this fibrous material.

TL;DR: In this article, the shape of the primary craze at the tip of a crack has been studied by optical microscopy for two grades of poly(methyl methacrylate).

TL;DR: The impact strength and modulus of polystyrene-graft copolymer blends could be made comparable to those of commercial rubber-modified impact polystyrenes by adjusting the fraction of copolymers in the blend as mentioned in this paper.

TL;DR: In this paper, the preparation and characterizations of several monomeric vinylimidazolium salts are presented from the quaternizations of 1-vinylimidine with n-alkyl iodides and with dimethyl sulphate.

TL;DR: In this paper, the compatibility of butadiene-acrylonitrile copolymers with polyvinyl chloride was investigated by phase contrast microscopy, differential scanning calorimetry and torsion pendulum analysis.

TL;DR: In this article, the translational diffusion coefficient for polystyrene in cyclohexane under theta conditions has been found to be concentration dependent, describable by an equation of the form: D ( c ) = D 0 (1 + k D c + …), in which k D is related to the weight-average molecular weight as k D = (4·1 ± 0·3) × 10 −4 M w d dl / g with with d = 0·48 ± 0.04

TL;DR: In this article, the authors used the Jacobson and Stockmayer theory to measure the molar cyclization equilibrium constants Kx for cyclics (CO.C6H4.CO.CH2.O) with x=3-9 in the undiluted polymer at 543K and in solution in 1-methyl naphthalene at 523K.

TL;DR: Differential scanning calorimetry was used to study the cure of several bisphenol-A epoxide/dicy (dicyandiamide, cyanoguanidine) systems in the temperature range 170-220°C.

TL;DR: In this article, the lattice parameters of the polymers from 2,4,6-octatriyne-1,8-diol, 1,8,diol-bis (phenyl urethane) were determined and based on these data and considering the mechanical properties and dichroism of the polymer crystals, it was concluded that polymerization proceeds according to a 1 4-addition to the triple bond system of the monomers.

TL;DR: In this article, an X-ray method is discussed for the formal characterization of three phases of fibres: the crystalline, intermediate and amorphous phase, and deviations from the regression line are discussed by using specially drawn non-crystalline templates with different densities.

TL;DR: In this paper, the experimental determination of bound rubber and the many factors affecting the value, in the case of the organic rubber/carbon black and silicone rubber/silica systems, are reviewed.

TL;DR: In this article, the effect of metal halides other than AlCl 3 into a TiCl 3 catalyst, by the reduction of TiCl 4 with various metal alkyls is examined.

TL;DR: The glass transition temperatures of fifteen poly(dimethyl siloxane) polymers and oligomers have been measured by differential scanning calorimetry as mentioned in this paper, and the thermomechanical behavior has also been examined using a torsional braid analyser and this has served to confirm the chain length dependence of Tg.

TL;DR: In this paper, a quantitative description of molecular orientation in one-way drawn poly(ethylene terephthalate) films is described using a combination of nuclear magnetic resonance (nmr), optical and X-ray diffraction measurements.

TL;DR: In this article, the transesterification of DMT with EG was investigated in the presence of various catalysts at 197°C, and the reaction was followed by the measurement of the quantity of methanol which distilled from the reaction vessel.

TL;DR: The die swell of the elastic liquid increased with shear rate and seemed to be asymptotic to the Newtonian die swell at low shear rates as mentioned in this paper, and the Reynolds number was about 10 −8.

TL;DR: In this article, high-resolution low-angle meridional and near-meridional X-ray diffraction data have been collected from specimens of α-keratin and various heavy-atom derivatives of α -keratin, and the observed reciprocal spacings of the layer lines satisfy the selection rule Z=m/h+n/P+s/P d where h = 67.1 A, P = 220 A, P d = 235 A and m, n and s are integers.

TL;DR: In this paper, the polycondensation of bis(2-hydroxyethyl) terephthalate (BHET) was kinetically investigated in the presence of zinc acetate as a catalyst at 283°C.

TL;DR: In this article, high impact cast sheets of poly(methyl methacrylate) (PMMA) were prepared by the interstitial polymerization of the monomer in a polyurethane (PU) gel which had been prepared in a state of dilution in the polyomer.

TL;DR: In this paper, a detailed study of light absorption characteristics, reaction rates, and molecular weights in radical polymerization of methyl methacrylate photoinitiated by Benzoin and benzoin methyl ether is presented.

TL;DR: In this article, semi-pinacol radicals were shown to act as terminating species in free radical polymerization of methyl methacrylate (MMA) at 30° and 70°C.

TL;DR: In this paper, the diffusion of linear polystyrene under non-theta conditions in butan-2-one has been studied by Rayleigh light scattered linewidth measurements for the molecular weight range of 2.08 × 106 to 8.7 × 106 and as a function of concentration.

TL;DR: The morphology and loss properties of polymeric composites of poly(methyl methacrylate) (PMMA) and polyurethane (PU) prepared according to an interstitial method have been studied as discussed by the authors.

TL;DR: The stress-strain behavior of ABS containing up to 33.5vol% of 10-40μm glass beads as filler was measured at one strain rate at room temperature as discussed by the authors.

TL;DR: In this paper, a commercial thermoelastic three block copolymer (styrene-isoprene-styrene) has been characterized with regard to its molecular weight, block length and original morphology.