Fiber distribution in oriented glass-reinforced plastics

The distribution of the fibers in the structure of a glass-reinforced plastic has been experimentally investigated. Data have been obtained on the distribution of interfiber distances, fiber diameters, and the angles between the lines of centers. Experimental histograms and distribution curves are constructed.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, Vol. 5, No. 2, pp. 282–287, March–April, 1969.     

Temperature dependence of the thermophysical properties of a Teflon — Bronze antifriction material

The effect of temperature and the concentration of the dispersed metallic filler on the thermophysical properties of a Teflon-based composition have been experimentally investigated. The results of the measurements of the thermophysical characteristics of the filled and unfilled Teflon are evaluated with allowance for the thermal conductivity of the components, their physicochemical interaction, and the change in the structure of the heterogeneous systems investigated.Deceased.A. M. Gor'kii Kiev State Pedagogical Institute; Institute of Colloidal Chemistry and the Chemistry of Water, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1053–1056, November–December, 1971.     

Spherulite boundaries and certain aspects of interspherulitic fracture

The morphology and properties of the interspherulitic boundaries in polyethylene specimens with ring-type spherulitic microstructure have been the subject of a microscopic and electron-microscopic investigation. It is shown that the structure and the strength of the boundaries depend on the orientation of the structural elements, of which the spherulites are composed. The strongest boundaries are those where the c axes of the crystals are oriented perpendicular to the interface. The parts of the boundaries where the crystals are in lateral contact serve as centers of brittle crack nucleation. The morphology of the interspherulitic boundaries is discussed with reference to the mechanism of spherulite formation. The possibility of controlling the boundary structure by regulating the supermolecular microstructure of the polymer is examined.Paton Institute of Electrowelding, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 3, pp. 391–395, May–June, 1969.     

Dependence of the properties of polycaproamide obtained in the presence of benzhydrazide on the symmetry type of the unit cell

The structure and properties of polycaproamide obtained in the presence of benzhydrazide have been studied. They are shown to depend on the duration of application of pressure in the mold. Under tensile deformation a transition from hexagonal to monoclinic polycaproamide takes place in the neck.Lugansk Machine-Building Institute. Institute of the Chemistry of High-Molecular Compounds, As UkrSSR, Kiev. Translated from Mekhanika Polimerov, Vol. 4, No. 6, pp. 1125–1127, November–December, 1968.     

Concerning the investigation of the supermolecular structure of polymers with a three-dimensional network

The results of an investigation of the structure and properties of a series of crosslinked polymers are presented. It is shown that the structure is determined by the chemical structure of the starting components and the method of synthesis.Institute of Chemistry of High-Molecular Compounds, Academy of Sciences of the Ukrainian SSR, Kiev. Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 5, pp. 934–936, September–October, 1970.     

Effect of liquid media on the deformation of the surface layers of a polymer-metal pair in sliding friction

The relation between the high-elastic component of polyurethane deformation and the deformation of the surface layers of metals has been investigated for sliding friction in various media. The surface layers of polymer and metal are plastically deformed. There is a certain correlation between the coefficient of friction and the amount of deformation.Kiev Institute of Civil Aviation Engineers. Translated from Mekhanika Polimerov, No. 1, pp. 147–149, January–February, 1970.     

Effect of liquid media on the weight,hardness, volume,and deformation of polyurethane

The resistance of polyurethane to aviation fluids and water has been investigated. The deformation of polyurethane directly exposed to these fluids has been determined. It is shown that polyurethane is insoluble in aviation fluids and sensitive to the action of acids and RDV liquid; it has good resistance to water and atmospheric conditions. The deformation that develops in the first hours of exposure subsequently shows little change.Kiev Institute of Civil Aviation Engineers. Translated from Mekhanika Polimerov, Vol. 5, No. 2, pp. 342–344, March–April, 1969.     

Effect of material structure on the stability of a laminated-plastic cylindrical shell

A compact equation is proposed for analyzing the stability of layered shells in relation to their structure. The case of a shell with split longitudinal-transverse winding subjected to hydrostatic pressure is investigated.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 1, pp. 147–150, January–February, 1971.     

Theory of filled polymers and the problem of modifying the structure and properties of polymers with fillers

An attempt is made to explain the effect of fillers on the structure and properties of polymers. The effect of fillers on the state of thermodynamic equilibrium and the stability of polymer structure and properties is also considered.Kiev Shevchenko State University. Translated from Mekhanika Polimerov, No. 6, pp. 1031–1041, November–December, 1970.     

Analogies and the modeling of composites

On the basis of the solution of a series of problems of the distribution of static and dynamic fields of various physical kinds in the microstructure of composite materials reinforced with dispersed particles or fibers analogies are established between the stress, displacement, temperature, electromagnetic, and other fields subject to certain similarity criteria imposed on the properties of the components.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1028–1037, November–December, 1969.     

Effect of fillers on the hardness and structural order of polymers

The effect of various finely dispersed filler particles differing in size, structure, and the chemical nature of the surface, on the hardness of one crystalline (polycaproamide) and two amorphous (polystyrene and polymethylmethacrylate) polymers has been experimentally investigated. The observed changes in hardness are related with a change in the structural order of the polymer under the influence of the filler and with the formation of structures of different strength by the fillers in the polymer.Kiev Shevchenko State University. Translated from Mekhanika Polimerov, Vol. 4, No. 6, pp. 1077–1081, November–December, 1968.     

Determination of the thickness of the surface layer on polymer blocks

A dependence of the thickness of the surface layer on the mechanical and wave characteristics of polymers has been obtained from joint solution of the equations of surface-wave motion and surface-layer equilibrium. From the dependence derived, the thicknesses of the surface layers have been calculated for four polymers. The dependence of surface-layer thickness on mechanical properties of the polymers and loading characteristics has been established.Institute of the Chemistry of High-Molecular-Weight Compounds, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 2, pp. 195–201, March–April, 1972.     

Effect of deformation on the supermolecular structure of PN-1 copolymer

It is shown that under the combined influence of temperature and tensile stresses the spherical structure of crosslinked PN-1 copolymer becomes ellipsoidal. The change of shape is associated with the zone of high-elastic deformation.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1129–1131, November–December, 1969.     

Determination of the main probabilistic characteristics of a process describing variations of the neuron membrane potential

A probabilistic model of the impulse activity of single neurons is constructed, assuming that the excitatory neural synapses receive Poisson streams of nervous impulses. Differential equations are derived for the distribution function of the process describing variations of the membrane potential. A Laplace-transformed solution is obtained. The distribution of the number of excitatory postsynaptic potentials arriving at the neuron between impulse generation instants is determined.Kiev University. Translated from Vychislitel'naya i Prikladnaya Matematika, No. 75, pp. 115–120, 1991.     

Effect of proton-electron irradiation on the strength of a glass-reinforced plastic and its components

The action of protons and electrons on the properties of glass strands under vacuum conditions has been experimentally investigated. The experimental procedure is described. The effects of irradiation, strain rate, and reduced temperature and pressure on the properties of glass reinforcement and glass-reinforced plastics are estimated.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev; Physicotechnical Institute of Low Temperatures, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 4, pp. 755–760, July–August, 1970.     

Theory of the elastic stability of compressible and incompressible composite media

The present article considers general problems of the theory of the elastic stability of composite media in the presence of finite and small precritical deformations with an arbitrary elastic-potential form. Our investigation was conducted for homogeneous and piecewise-homogeneous anisotropic media. Numerical results were obtained for laminar media. We have elucidated the case in which there is internal loss of stability (in the material structure) for compressible materials with small deformations (plane problem) and for incompressible materials with highly elastic deformations (plane and three-dimensional problems) for the Treloar and Mooney potentials.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 2, pp. 267–275, March–April, 1972.     

Investigation of the mechanical properties and internal stress field of directionally reinforced materials in transverse tension

The dependence of the transverse Young's modulus and Poisson's ration on the reinforcement ratio, type of structure, and internal fiber radius has been investigated. The microstress field in the structure of a composite in transverse tension is analyzed. Simple approximate expressions, which can be used to determine the corresponding mechanical characteristics without analyzing the state of stress, are obtained from the exact equations. A medium reinforced with doubly periodic groups is taken as a model. The exact solutions of the problem are obtained by means of elliptic functions.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 5, pp. 812–817, September–October, 1970.     

Thermal conductivity of reinforced media

On the basis of a model of an inhomogeneous body a solution is obtained for the problem of the temperature field and thermal conductivities of reinforced media, whose structure is formed by a doubly periodic system of n hollow cylinders of arbitrary diameter with the space between filled by a homogeneous medium. The thermophysical characteristics of the components are assumed given.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, Vol. 4, No. 4, pp. 749–751, July–August, 1968.     

Effect of ultrasound on the properties of a glass-reinforced plastic

It is shown that removing paraffin size from the glass strands by means of ultrasound has little effect on their strength, improves the structure of the material, and raises the mechanical strength of the GRP by 11–12%. An ultrasonic strand cleaner employing focusing piezoelectric ceramic transducers is described.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 3, pp. 546–548, May–June, 1969.     

Study of the strength and coefficients of friction of metal-containing polymers based on heteropolyacids

The strength and coefficients of friction of new heat-resistant composite materials consisting of metallopolymers of iron and cobalt based on molybdosilicic and tungstosilicic heteropolyacids have been studied. It has been established that the use of a lubricant in the frication of metallopolymers over steel brings about a sharper deerease in the coefficients of friction than in the case of the friction of the compact material; this is due to the ability of the metallopolymers to absorb the lubricant material.Kiev Automobile-Road Institute. Translated from Mekhanika Polimerov, No. 5, pp. 931–933, September–October, 1973.