Theory of low-temperature elasticity of amorphous polymers: Deformation at a constant rate and relaxation of deforming stress.

The effect of temperature variations over a wide range on the rheological properties of amorphous polymers with high rubber-like elasticity (elastomers) is discussed. A theoretical study of the transition from the deformation state of a warm elastomer to the state of a frozen one, the effects of structural-strain glass transition and forced elasticity was done. Two types of mechanical testing of polymer samples are considered in detail: slow tensile deformation at a constant rate and relaxation of the deforming stress after deformation stops. The study was carried out on the basis of the previously proposed molecular-kinetic model of the processes of highly elastic deformation of amorphous polymers and the corresponding nonlinear rheological equation (V. D. Natsik and H. V. Rusakova, Fiz. Nizk. Temp.48, 281 (2022) [Low Temp. Phys. 48, 253 (2022)]). [ABSTRACT FROM AUTHOR]