Ca. Hieber, CORRELATIONS FOR THE QUIESCENT CRYSTALLIZATION KINETICS OF ISOTACTIC POLYPROPYLENE AND POLY(ETHYLENE-TEREPHTHALATE), Polymer, 36(7), 1995, pp. 1455-1467
The Nakamura equation is used to generate a direct relation (first-ord
er differential equation) between the Avrami and Ozawa crystallization
rate constants. As a result, it is possible to compare isothermal and
constant-cooling-rate crystallization data in a consistent manner. Th
is is done for isotactic polypropylene (i-PP) and poly(ethylene tereph
thalate), based upon data available from the literature. Resulting cor
relations are obtained for these two materials at atmospheric pressure
as well as for i-PP at elevated pressure. The results corroborate tha
t the maximum crystallization rate occurs approximately midway between
the glass-transition and melting temperatures. In addition, the resul
ts imply that there is no need to explicitly incorporate an induction
time when the modelling is based upon the Nakamura equation.