Crystallization kinetics of poly( p-phenylene sulphide): effect of molecular weight

Abstract

The crystallization behaviour of poly( p-phenylene sulphide) (PPS) has been studied in terms of linear crystal growth rates and overall rates of bulk crystallization as functions of molecular weight and temperature. In addition, nucleation densities were estimated for PPS crystallized from the melt. The overall rate of bulk crystallization was described by the Avrami equation. In the range of molecular weights studied (24 000–63 000), crystal growth rates and overall rates of bulk crystallization decreased as the molecular weight increased. However, the effect was not particularly large. The estimated nucleation densities indicated a decrease by a factor of 32 as the molecular weight decreased. The linear crystal growth rate data were analysed in terms of several proposed models. The data seemed to conform very well to an ‘inverse’ logarithmic function of the number-average molecular weight recently proposed by Cheng and Wunderlich.