Isophasic transitions in polytrifluorochloroethylene

Abstract

AbstractThrough determination of dynamic mechanical properties (sound velocity and damping factor) over the temperature range from −160 to 200°C. and frequency range from 4 to 16 kcycles/sec. evidence is found for the existence of two isophasic transition temperatures in polytrifluorochloroethylene: one at −58°C. and the other at 50°C. Both transitions are associated with motion in the main chain of the polymer, which is first excited at −58°C. for the molecular segments which are more freely rotating (because they are located near network defects) and at 50°C. for the majority of the chain elements in the amorphous regions. The transition point at −58°C. is regarded as the glass transition temperature for polytrifluorochloroethylene. The experimental results are discussed on the basis of the structure of the polymer examined, and a comparison is made between dynamic mechanical data and data obtained by measurements of specific volume, nuclear magnetic resonance, and dielectric losses.