Structure-sensitive liquid flowable compositions based on polyvinyl alcohol and silicotungstic acid

Conditions of the formation of structure-sensitive liquid flowable media based on 1.5 and 10% aqueous solutions of polyvinyl alcohol containing silicotungstic acid and water-soluble carboxy-methylcellulose in the form of its potassium salt (Na-CMC) are examined. Rheological, optical, and dielectric relaxation methods revealed the formation of several types of interpolymer complexes in the examined liquid flowable media. This leads to the formation of associates and an increase in the molecular mobility of the macromolecules and their fragments. The structure and properties of the complexes depend on the composition of the media as well as the method of introducing polyacids. It was found that it was possible to control the structure of such solutions by applying a mechanical of magnetic field. The compositions obtained can be used for producing anisotropic light-, electric-, and heat-sensitive film materials, as well as sensors of different types.Presented at the 10th International Conference on the Mechanics of Composite Materials (Riga, April 20–23, 1998).Institute of General and Inorganic Chemistry, Belarus Academy of Sciences, Minsk, Belarus. Translated from Mekhanika Kompozitnykh Materialov, Vol. 34, No. 3, pp. 413–424, May–June, 1998.     

Certain correlations between the physico-chemical properties and breaking characteristics of polyvinyl alcohol fibers

The experimental correlation between the structural orientation of polyvinyl alcohol fibers and their breaking characteristics is discussed and explained.Leningrad Branch, All-Union Scientific-Research Institute of Synthetic Fibers. Translated from Mekhanika Polimerov, Vol. 5, No. 2, pp. 349–351, March–April, 1969.     

Antifriction and mechanical properties of polymer compositions based on silicone adhesives

A comparative investigation has been made of the antifriction and mechanical properties of polymer compositions based on K-400 silicone adhesive and fillers in the form of finely dispersed powdered polymers (tetrafluoroethylene, Kapron, polyethylene), graphite, sawdust, B-83 babbitt, and a lubricant^–US-2 grease. The antifriction properties of these materials are not inferior to those of some common nonferrous metals (B-83 babbitt, TsAM9-1.5 zinc alloy, OTsS5-5-5 bronze). The rational range of application of the compositions investigated is indicated.Rostov-on-Don Institute of Railroad Transport Engineers. Translated from Mekhanika Polimerov, No. 5, pp. 937–940, September–October, 1969.     

Temperature dependence of the deformation properties of compositions based on polyethylene and polyisobutylene

The temperature dependence of the deformation properties (deformability and recoverability) of compositions based on low-density polyethylene and polyisobutylene has been investigated. For two-component polyethylene—polyisobutylene systems this dependence varies with the component ratio. Introducing a filler (talc) reduces the recoverability of the compositions owing to increases in both the delayed high-elastic deformation and the flowability. The deformation properties of compositions plasticized with paraffin change abruptly at the melting point of the latter.Moldavian Scientific-Research Institute of the Food Industry, Kishinev. Translated from Mekhanika Polimerov, No. 4, pp. 758–760, July–August, 1971.     

Structure and rheological properties of polymers

The viscoelastic properties of linear flexible-chain polymers with a narrow distribution, for which M > 5M_c (M_c corresponds to the formation of a three-dimensional entanglement network), their mixtures, and concentrated solutions are examined. It is established that under the influence of deformation the polymer may undergo a transition to the rubbery state, which thus defines the limit of its flow state; this transition is also observed in mixtures and concentrated solutions of high-molecular-weight polymers with a narrow distribution. The relative simplicity of the rheological properties of linear high-molecular-weight polymers and their mixtures is determined by the sharpness of the transition to the rubbery state. It has been found that in mixtures of high-molecular-weight polymers the apparent viscosity mechanism associated with a decrease in dissipative losses on transition of the high-molecular-weight components to the rubbery state is dominant; on a broad range of molecular weights (M > M_c), and moreover for polymer solutions, the decrease in entanglement network density under the influence of deformation acquires considerable importance. It is established that the separate effect of the high-molecular-weight components on the viscoelastic properties of their mixtures contradicts the idea of a random network of macromolecular chains. Attention is drawn to the temperature dependence of the viscosity of polymers with a narrow distribution and the dynamic properties of their mixtures. Problems of theoretical and practical interest associated with the particular rheological properties of polymer systems at high deformation rates are defined.     

Some properties of filled polyvinyl chloride

The effect of TiO₂, SiO₂, and carbon fillers on rigid, partly plasticized PVC has been investigated. Interaction in the polymer-filler system improves certain important properties — hardness, stiffness, wear resistance, etc., — the effect of the fillers being highly specific.M. V. Lomonosov Odessa Technological Institute. Translated from Mekhanika Polimerov, No. 1, pp 124–126, January–February, 1970.     

Thermomechanical properties of polyvinyl chloride macromolecules

The coefficient of thermoelasticity d ln h ² /dT, characterizing the mechanical properties of the investigated polymer, is computed. This coefficient is found to have a negative value, which indicates that the absolute value of the minimum of the potential energy U() corresponds to the trans isomer. The difference U of the minima of the potential energy for two rotational isomers is also calculated starting from the ratiof _e/f.Lodz Polytechnic Institute. Translated from Mekhanika Polimerov, No. 5, pp. 784–789, September–October, 1971.     

Relationship between internal stresses and rheological properties

It is shown that, under practically identical viscous-shear conditions, the correlation between orientation and relaxation processes taking place in an extruder die is different for different brands and batches of shock-resistant polystyrene. It has been found that the material with the the higher orientation tendency in the viscous-fluid state in the die is oriented more strongly at the same conditions in the Mackian elasticity state in the reception and pulling of the extruded polymer. It is shown that the thermal shrinkage of the sheets correlates reasonably well with the degree of swelling and the Mackian elasticity deformation of the polymer."Plastpolimer" Scientific-Industrical Association, Leningrad. Translated from Mekhanika Polimerov, No. 5, pp. 952–955, September–October, 1972.     

关于正整数有序分拆的一些恒等式和n-colour有序分拆的两个组合性质

研究了正整数的无序分拆与有序分拆的关系.给出了正整数的无序分拆与有序分拆的一些恒等式.并且利用菲波拉契数与正整数n分拆成不含分部量1的有序分拆数的关系给出了n-colour有序分拆的两个组合性质.     

Friction and rheological properties of resin-impregnated glass tape

The dependence of the dynamic coefficient of friction of resin-impregnated glass tape on the sliding speed over the mandrel surface and the viscosity of the resin is derived. The formulas obtained are confirmed by the results of experiments which indicate a linear dependence of the coefficient of friction on the sliding speed of the tape over a metal mandrel. Graphically, this dependence is expressed by straight lines with a common origin and a slope that increases with the viscosity of the resin. The coefficient of friction of glass tape sliding over a prewound layer at low speeds also has a linear dependence. At high speeds the dependence takes the form of a damped curve.Translated from Mekhanika Polimoerov, No. 1, pp. 166–170, January–February, 1976.     

Dynamic mechanical properties of multicomponent polymeric compositions

The mechanical relaxation processes in rubber-polymer compositions have been investigated by the forced nonresonance vibration method. A method of evaluating black-filled polymer mixtures with advantages over microscopic methods is proposed.Scientific-Research Institute of the Tire Industry, Moscow. V. I. Lenin Moscow State Pedagogical Institute, Laboratory of Problems in Polymer Physics. Translated from Mekhanika Polimerov, No. 1, pp. 138–141, January–February, 1970.     

Structure and properties of nanoparticles used in paper compositions

The structural characteristics of cellulose and chalk nanoparticles were studied by the methods of electronic microscopy, laser light scattering, X-ray diffraction, sorption, water retention, and some others. It is shown that nanocellulose consists of rodlike particles having an increased hydrophility. In contrast to the organic nanocellulose, the inorganic nanochalk contains ellipsoidal particles having a relatively low hydrohpility. Paper samples containing cellulose fibers and nanoparticles, as well as flocking and sizing agents, were made and their properties were tested. Testing the mechanical properties of the paper samples showed that the introduction of the hydrophilic cellulose nanoparticles, having a developed surface, decreased the porosity and sharply increased the strength of the final paper. In contrast to this result, chalk nanoparticles did not improve the physicomechanical properties of paper, because of the low bonding between the inorganic particles and the organic cellulose fibrils.     

Effect of the structure of stereospecific rubbers on their rheological properties

The authors discuss the viscosity properties of stereospecific rubbers and the relationship of these properties to structure. The dynamic characteristics of rubbers have been mearured on a board frequency interval, and it is shown that the moduli of elasticity and loss tangents vary considerably with frequency. The relationship between the rheological characteristics and structure of these rubbers and certain of their technological properties is examined.Mekhanika Polimerov, Vol. 4, No. 3, pp. 387–393, 1968