Internal stresses in crystallizing polymer coatings

The effect of crystalline structure on the internal stresses in polyethylene coatings has been studied. An equation for the internal stresses in crystallizing polymer coatings has been derived. The important role of orientation processes is demonstrated.Leningrad Lensovet Technological Institute. Translated from Mekhanika Polimerov, Vol. 4, No. 6, pp. 992–996, November–December, 1968.     

Fractal analysis of thermally sprayed coatings

Functional performance of thermally sprayed coatings depends to a large degree on their surface topography. Surface topography of coatings was studied by analyzing numerically data sets aquired by contact profilometry. The effect of spraying method and powder composition was explored for a range of coatings. The effect of coating composition was studied for cermet coatings flame sprayed with mixtures of Ni-5%Al with ZrO₂-30%CaO. To characterize the coating surface topography, multifractal analysis was performed. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of internal stresses on the wear resistance of epoxy coatings

The results of wear tests on ED-5 epoxy coatings are used to derive a relation between internal stresses, modulus of elasticity, and wear resistance. During wear the internal tensile stresses diminish, the rate of decrease depending on the initial stress state, the material of the abrading body, and the test conditions. The thickness of the coating affects wear resistance up to a certain value; for ED-5 the limiting thickness is 500 microns.Mekhanika Polimerov, Vol. 1, No. 2, pp. 123–128, 1965     

Effect of fillers and solvents on the properties of polystyrene coatings

The mechanism of coating formation from solutions of atactic polystyrene in xylene and carbon tetrachloride has been investigated. It has been established that, as the filler content increases, in coatings formed from polystyrene solutions containing an evaporating solvent the growth of the internal stresses and the thermophysical characteristics is characterized by similarity of slope, as distinct from the case of coatings obtained from systems containing a polymerizing solvent. It is shown that the nature of the solvent has an important effect on the character of the interaction at the polymer—filler interface and on the structure and properties of the coatings.Kucherenko Central Scientific-Research Institute of Structural Design. Institute of Physical Chemistry, AS USSR, Moscow. Translated from Mekhanika Polimerov, Vol. 4, No. 6, pp. 1127–1129, November–December, 1968.     

A study of the effect of the nature and microstructure of fibers on internal stresses in unwoven materials

This investigation was concerned with the effect of the nature and microstructure of fibers on internal stresses produced during the fabrication of materials made by impregnating matted fibers (lavsan, nitron, polyvinylchloride, vinol) with polymer dispersions. It was shown that the rate of growth and relaxation of internal stresses depend on the nature of the fibers and the film-forming materials and on the concentration and composition of the coagulant solutions.Mekhanika Polimerov, Vol. 2, No. 6, pp. 808–812, 1966     

Stresses in various resins cured on glass films

By using Sanzharovskii's method for determining the stresses in lacquer coatings and employing as a model a layer of resin deposited on a glass film, it is possible to simulate the processes that take place in glass-reinforced plastics and determine the stresses that develop in different resins cured under various conditions. The method proposed makes it possible to estimate the effect on the stresses of the shrinkage of the resin, its elasticity, and the difference in the coefficients of thermal expansion of the resin and the glass. Such an investigation is desirable before selecting the composition of the resin, additional organic or mineral fillers and elasticizers, and the optimal curing regime for glass-reinforced plastics.All-Union Scientific-Research Institute of Aviation Materials, Moscow. Translated from Mekhanika Polimerov, No. 3, pp. 481–486, May–June, 1969.     

Investigation of the temperature residual stresses and strains in thick-walled wound reinforced plastic products

The kinetics of the temperature residual stresses and strains in thick-walled reinforced-plastic cylinders and rings have been experimentally investigated employing a special procedure for continuously monitoring the internal strains and stresses in the various zones of the semifinished product during the heat treatment stage. The effect of the resin polymerization (polycondensation) temperature and the mandrel material on the magnitude and distribution of the temperature stresses is considered. The total residual stresses have been determined by a nondestructive strain-gauge method with differentiation of the components.Translated from Mekhanika Polimerov, No. 6, pp. 1040–1046, November–December, 1971.     

Effect of the nature of the solvent on the mechanical and adhesion properties of atactic polystyrene

The effect of the supermolecular structure on the internal stresses and adhesion of coatings obtained from solutions of atactic polystyrene has been investigated. The structure of the coatings depends on the nature of the solvent and is nonuniform with respect to the morphology, size, distribution, and state of order of the structural elements. The greatest strength and adhesion correspond to fibrillar structures.Kucherenko Central Scientific Research Institute of Building Structures, Moscow; Institute of Physical Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Mekhanika Polimerov, No. 5, pp. 793–797, September–October, 1969.     

Investigation of internal stresses in glass-reinforced plastics

The strength properties of and internal stresses in epoxy and epoxyphenol resins and GRPs based on them are investigated using an optical method of determining internal stresses. The GRPs had tape and fabric reinforcement. Compared with the internal stresses in unplasticized specimens, the stresses in pure resin films and in GRPs based on plasticized resins are found to be smaller. It is shown that the distribution of internal stresses in GRPs is anisotropic. The highest internal stresses are observed in tape-reinforced GRPs in a direction normal to the fibers. Glass reinforcement in two directions at right angles reduces the internal stresses in GRPs as compared with pure resin films. In both reinforced and unreinforced films, the internal stresses depend on the curing conditions.Mekhanika polimerov, Vol. 1, No. 1, pp. 82–88, 1965     

A study of the life of alkyd coatings

The effect of the conditions of formation and aging on the life of alkyd coatings is studied. It is shown that the life of alkyd coatings aged under various conditions can be expressed by the general equation =Ae^–ax The relationship between the life of alkyd coatings and curing temperature is linear. It is observed that the conditions of aging have no effect on the rupture energy or ₀, but cause a substantial change in the distribution of the lines =f(1/T_f). Cross-linkage of alkyd coatings due to the action of heat, light, and moisture, under various conditions of aging, is accompanied by an increase in rupture energy with increase in the internal stresses.Mekhanika Polimerov, Vol. 1, No. 3, pp. 68–76, 1965