RELAXATION PHENOMENA IN POLYMER BLENDS BASED ON POLY(ETHYLENE-TEREPHTHALATE)

Amorphous blends of PET with additives based on polyvinylbutyral and segmented polyurethanes containing soft and hard blocks of different lengths and different concentrations of polar groups were studied by relaxation spectrometry. Computer resolution of maxima of dielectric and mechanical loss tangents, as well as of stress relaxation curves, was carried out, and the preferential character of the effect of additives on the mobility of kinetic units of different types was established. Experimental evidence was interpreted with account of possible structural heterogeneity in amorphous PET and polymer redistribution between microregions with different degrees of ordering as a result of plasticizing action of the additives.