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The x-ray patterns of solid phase polymers are widely used to characterize the structures. They can be used, among others things, to calculate the degree of crystallinity, the crystalline particle size, and the lattice distortions. However, it is not perfectly clear how the characteristics of the structure effect the obtained diffractograms. The main aim of the present work is to explain what kind of diffraction patterns can be obtained from a hypothetical structure of a polymer. The effect of the following structural parameters were investigated: degree of crystallinity, crystalline particle size, lattice distortions of the first and second kind, and amorphous background. The changes of the diffraction patterns depending on these varied factors were followed. The light diffraction patterns were produced by a modified Schlieren 80 apparatus. The polymer segments were modelled by point-like scattering centers. From these, the models of an ideal crystal and the lattice distortion of the first and second kind were prepared. The crystalline particle size was varied by cutting the original mask. In the amorphous background the minimum distances of two scattering centers were altered. The light diffraction patterns were produced also by rotating the mask, and the x-ray diagram of the unoriented polycrystalline samples could be reproduced. The intensities of the obtained patterns were measured by a microdensitometer. With the help of the diagrams, both qualitative and quantitative conclusions can be obtained about the relation between the mask and its diffraction pattern.

In the thermal oxidation of low density polyethylene (PE) in the melt phase and isotactic polypropylene (PP) in the solid phase, the changes in molecular weight distribution (MWD), weight average molecular weights (Mω), and average number of chain scissions have been studied by gel permeation chromatography (GPC). It has been established that in the case of PP degradation, there is an increase in molecular weight during the induction period both at 80 and 760 torr with simultaneous scission of the macromolecules. In contrast, a similar tendency can be observed in the degradation of PE only at very low (20 torr) pressures, i.e., the degree of molecular weight increases proportional to the length of induction period. For both polymers at the temperature of investigations, considerable molecular weight decrease can be detected both at reduced and atmospheric pressures at the onset of measurable oxygen absorption. In the maximum rate oxidation of PE and PP, the increase of temperature, oxygen pressure, and degradation time each causes a shift of the MWD curves towards lower molecular weights. The average number of chain scissions against the amount of absorbed oxygen was also studied. It has been found that the average number of chain scissions per 1 mole absorbed oxygen is considerably higher for PE than for PP. Molecular weight studies performed in the kinetic range of thermal oxidation show that under given conditions, Intermolecular combination reactions and chain scissions may occur simultaneously.

A new method is proposed for determining the spreading factor h(v) in the Tung integral equation, based on moment analysis of original (uncorrected) and corrected, normal-flow chromatograms of calibration standards. The reliability of the new procedure has been verified on model and computer-generated chromatograms, and tested experimentally on standard GPC columns as well as on microcolumns used in high-speed gel-permeation chromatography; its accuracy has been compared with that of known methods. The proposed method is particularly suited to fast gel-permeation chromatography where, by trading the speed of analysis for efficiency, one can dispense with the knowledge of the molecular-weight averages of calibration standards. If a well-characterized sample having a broad molecular-weight distribution is available, the shape of the function h(v) can be determined with sufficient accuracy from a single chromatogram.

Nylon 6,6 cord is used as reinforcement in rubber products (e.g., tires, hoses, and belts). The problem of bonding rubber to textile cords is due to the big difference between the surface properties. To obtain a durable reinforced rubber product, it is necessary to produce a bond strong enough to resist the different conditions, for example, high temperature, cyclic tension, compression loads, and shock, depending on the applied rubber product. Choosing a suitable adhesive system and addition of an adhesion promoter into the rubber compound are factors which play a very important role. Many other factors are known to affect the bond strength obtained with resorcinol formaldehyde latex (RFL) adhesives. For example, method of RFL preparation, its composition, amount of adhesive applied to cords, its distribution on the cord, heat treatment conditions after dipping, method of storing dipped cord, composition of rubber compound, and vulcanization conditions are factors affecting the cord-to-rubber bo...

Homo- and copolymers of monomers having vinyl groups with large, rigid side chains were investigated by size-exclusion chromatography and small-angle X-ray diffractometry in the solid state. The distributions of the molecular dimensions in dilute solutions and the distributions of the inhomogeneities of electron density in solid materials showed many similarities, and on the basis of these finding some conclusions are drawn concerning the molecular structure in the solid state and in dilute solutions, and also on the nature of the separation mechanism in size-exclusion chromatography.

Oxidation of atactic polypropylene (PPH) has been used in the preparation and characterization of hydroperoxide PPOOH, from which radicals PPOO- were generated. Their interaction with 2,6-ditert-butyl-4-methylphenol (BHT) demonstrated transformations of the antioxidant, leading, on the one hand, to peroxycyclohexadienone, PPOO-CHD, in which the residue of reacted BHT is bound on PPOO and, on the other, to compounds resulting from the oxidative coupling of BHT; of these, 4,4′-ethylenebis (2,6-ditert-butylphenol) and 3,3′,5,5′-tetratert-butylstilbenequinone were identified. Further products of coupling are light- to deep- brown; some of them contain phenolic and quinomethinoidic functions. PPOO-CHD may take an active part in the atmospheric ageing of PPH arising from decomposition caused by heat, radiation or catalytic impurities.

Weight average molecular weights were calculated for several sets of polymer samples from GPC chromatograms using different evaluation methods. The results were compared with light scattering data in order to check the reliability of individual evaluation procedures: data obtained using the direct calibration were compared with those calculated via the Benoit universal calibration empolying (i) directly measured Kuhn-Mark-Houwink constants and (ii) Weiss-Cohn-Ginsberg iterative calculation. Gewichtsmittlere Molekulargewichte wurden fur eine Reihe von Polymerproben aus Gelchromatogrammen ermittelt, wobei verschiedene Auswertemethoden verwandt wurden. Die Ergebnisse wurden mit Lichtstreuungsmessungen verglichen, um die Zuverlassigkeit der einzelnen Auswertungen zu uberprufen. Erhaltene Daten uber die Direkt-Kalibrierung wurden mit solchen aus der Benoit-Universalkalibrierung einmal unter Anwendung der direkt gemessenen Kuhn-Mark-Houwink-Konstanten, zum anderen aus der Weiss-Cohn-Ginsberg-Naherungsmethode verglichen.

The solid-, cholesteric- and liquid-state polymerizations of cholesteryl-vinyl-succinate (CVS) are studied. Only one of the three polymorphic modifications of CVS oligomerizes in the solid state into oligomers of degree P = 2 to 6 in a homogeneous topochemical reaction. The rate of polymerization in the cholesteric state is lower than that in the liquid state at the same temperature. Kinetic constants were measured at 85° using benzoyl peroxide as initiator and the Banfield radical, giving Eoverall = 15.4, 36.4 kcal/mole−1; f = 0.52, 0.19; k p /k t 1 2 = 0.0167, 0.0192 , (1/mole sec) 1 2 , ( E p − 1 2 E t ) = 0.40, 21.4 kcal mole−1. The values refer to the liquid- and the cholesteric-state reactions, respectively. The average degree of polymerization is low in both cases ( P = 20 and 22 ). It was concluded that the molecular weights are controlled by chain transfer and that the initiation reaction is mostly dependent on the phase where the reaction takes place.

Polymers were prepared from the phenyl and p-alkoxy-phenyl esters of p-acryloyloxy benzoic acid. These polymers resulted in anisotropic systems during the cooling of their melt or on concentrating their solutions. The anisotropic polymers had a Schlieren texture. On the basis of small- and wide-angle X-ray scattering the polymers are identified as non-crystalline, the diffuse reflections are related to their molecular dimensions. By GPC in sym-trichloro benzene a broad distribution of molecular dimensions was observed where the number average molecular dimension corresponded to that measured in bulk. The average degree of polymerization is about the same for the five polymers. The polymer molecules are cylinders of 8–10 nm length and 2.5-3.9 nm diameter, which form the anisotropic state by close packing. The polymer molecule cylinders are made up of aperiodic helices, therefore the nematic state becomes glassy on cooling without formation of any crystalline polymer.

The steric factors σ of homopolymers of ethyl, n-butyl, and n-octyl methacrylate, of equimolar random and alternating copolymers of these monomers with styrene, and of polystyrene, were determined by measuring intrinsic viscosities in a good solvent (butanone, 25°C) and extrapolating the data thus obtained to zero molecular weight of the polymer. For all comonomeric pairs under investigation, the σ2 of an equimolar random copolymer and, particularly, of an alternating copolymer, is higher than the arithmetic mean (σ + σ)/2 of the σ2 values of the parent homopolymers. The positive deviation from the linear dependence of σ2 on the copolymer composition, expressed as an increment of σ2, is proportional to the mole fraction of alternating dyads in the copolymer chain with in the limits of experimental error. The effect of copolymer microstructure on the unperturbed dimensions of the chains has been compared for equimolar copolymers of styrene with methyl, ethyl, n-butyl, and n-octyl methacrylate by using a relative increment ξ defined as the ratio of σ2 of the alternating copolymer to (σ + σ)/2. The dependence of ξ on the number of carbon atoms in the alcohol substituent of the methacrylate component of the copolymer seems to exhibit a maximum for ethyl methacrylate.

Methods are proposed to transform GPG chromatograms into molecular mass distributions /MMD/ using the universal calibration and the intrinsic viscosity of the material measured at GPC circumstances, and in conditions, for which KMHS-constants are known. The results of the calculation are the MMD and the interrelation between the Kuhn-Mark-Houwink-Sakurada constans, K and a for GPC circumstances. It is also shown, that as a simplification a-values available for any condition can be used for the calculation using the experimentally measured intrinsic viscosities in GPC circumstances and within circumstances, for wich KMHS-constants are known.