A comparative study of the kinetic theories of the glass transition phenomenon in high polymers

Abstract

AbstractThe effect of thermal history on the glass transition temperature (Tg) of poly(vinyl chloride) was studied. The parameters like the hole energy (Eh), the activation energy for the disappearance of holes (Ej), the activation enthalpy for the structural relaxation (Δh1* and Δh2*) and the activation energy for the glass transition process (E) were calculated. The increase of Eh value with the increase in Tg value shows that there exists a holesize distribution. The Ej (26.9 ± 0.5 kcal/mol) value calculated according to Wunderlich's treatment, the Δh1* (27.8 ± 0.6 kcal/mol) value obtained by Moynihan's procedure and the E (35.3 kcal/mol) value from Barton‐Critchley's method agree well with one another in the poly(vinyl chloride) system. The Δh2* quantity, obtained through Moynihan's formulations, increase as the rate of heating was increased, a result similar to the variation of Eh value with the rate of heating.