PLASTIC-DEFORMATION KINETICS FOR GLASSY-POLYMERS AND BLENDS

Measurements of the plastic deformation kinetics for several glassy (PS, PC, PI-polyimide, PET, epoxy-amine network), semi crystalline polymers (PBT, PET) and blends (ABS, PC:ABS, PC: PBT) were performed for the unidirectional compression loading conditions by using constant temperature deformation calorimetry. The experiments have permitted us to follow the changes of the mechanical work (A), the heat of deformation (Q) and differences between these quantities, i.e., internal energy (DELTA-U) stored in samples during their loading and unloading. Experiments have shown that the large portion (45-85%) of the mechanical work of deformation (A) is converted to heat (Q). The rest of A is converted to internal energy (DELTA-U) stored in deformed samples. DELTA-U is quite high as compared with metals [1,2]. After complete unloading of plastically deformed samples, i.e., samples carrying irrversible at T(def)plastic deformation (epsilon-irr), some amount DELTA-(DELTA-U) of stored energy disappeared. The amount of (DELTA-U) and DELTA(DELTA-U) are different for different polymers. All data are analyzed in the framework of the model proposed in [3,4]. The experiments support the deformation model where the plasticity of glassy polymers is the process of nucleation and development of so-called PDs-plastic local shear defects of nonconformational and nondilatational nature.