Tribological properties of an antifriction polymer modified by severe plastic deformation

The possibility of applying severe plastic deformation technologies to improving the tribological characteristics of semicrystalline antifriction polymers was studied. By the example of Nylon 6 subjected to equal-channel multiple angular extrusion, it was shown that severe plastic deformation favors a significant (more than three orders of magnitude) increase in the wear resistance of polymer and a 15–20% decrease in its friction coefficient. There are also increases in the maximum allowable contact pressure and temperature in the friction zone, at which the wear and the friction coefficients are stable.     

Modification of polyamide-6 structure by combined methods of solid-phase extrusion

Potentialities of new combined deformation schemes, including the solid-state extrusion through conical die (ED) and equal-channel multiple angle extrusion (ECMAE) implemented in different sequences to modify the structure and properties of semicrystalline polymers, have been studied for polyamide-6 (PA-6) as an example. It is shown that deformation by the ED–ECMAE scheme gives the best complex of physical and mechanical properties. A significal improvement of elastic and strength properties of PA-6 with a conserved high level of plastic characteristics has been observed.     

Solid-phase extrusion of polyamide under simple shear

The advantages of new simple-shear methods of severe plastic deformation (equal-channel multiple angular extrusion, T-type extrusion, and twist extrusion) are examined for polyamides from the viewpoint of the structural modification of flexible-chain semicrystalline polymers. The effect of the deformation scheme and mode and the extrusion temperature and rate on the physicomechanical characteristics of the processed polymers are studied. The behavior of the material and its specific features are considered with respect to the conditions of solid-phase extrusion.     

Mechanisms for flow and forced high elasticity of cross-linked polymers

A quantitative model is proposed for flow and forced high elasticity of cross-linked polymers based on the cluster model of amorphous state structure. The flow process is seen as the loss of displacement stability by the clusters, while forced high elasticity is related to the mechanical devitrification of the softpack matrix. Fractal analysis was used to show a turbulent regime for the forced high elasticity of cross-linked polymers.Kabardino-Balkariya State University, Nal'chik. Russia. Donetsk Physics and Mechanical Sciences University. Ukraine. Branch of the Institute of Ecology. Kashkhatau, Kabardino-Balkariya. Russia. Center for Composite Materials, Moscow State Open University, Russia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 32, No. 2, pp. 270–278, March–April, 1996.     

Effect of Filler Aggregation on Properties of a Composite Based on Epoxy Polymer

The plasticity of a composite based on epoxy polymer was studied as influenced by the concentration of the filler, nanosized powders containing aggregates of strongly bound ZrO₂ particles.