SPECIFIC FEATURES OF DEFORMATION OF POLYM ERS PRODUCING LIQUID-CRYSTALLINE PHASE UNDER SHORT-TERM AND LONG-TERM LOADING

Mechanical properties of uniaxially oriented polyamides based on poly- n-benzamides prepared from lyotropic solutions and polyesters of hydro xybenzoic and hydroxyhaphthoic acids prepared from thermotropic melts were studied under tensile drawing, stress relaxation, and dynamic loa ding as a function of time and temperature. Tensile drawing was shown to be accompanied by the development of stable structures, which were characterized by constant current modulus, which was independent of te mperature. At elevated temperatures, the intensity of stress relaxatio n was found to decrease with increasing the draw ratio. Cyclic loading was shown to decrease polymer compliance. The stress-strain diagrams of tensile drawing of various polymers at different temperatures were summarized