EFFECT OF CHEMICAL-STRUCTURE OF AMORPHOUS POLYMERS ON HEAT-CAPACITY DIFFERENCE AT GLASS-TRANSITION TEMPERATURE

The heat capacity of 21 kinds of glassy polymers, mainly synthesized i n our laboratory, was measured by differential scanning calorimetry. G lass transition temperature (T-g) and the heat capacity difference bet ween the molten state and the glassy state (Delta C-p) at T-g were eva luated. A linear relationship was obtained between Delta C-p and T-g f or almost all glassy polymers including engineering plastics, in a tem perature range from 230 to 520 K, except for those having large side c hains and/or inter-molecular hydrogen bondings. It was suggested that configurational entropic factors must be taken into consideration for analyzing glass transition.