Effects of crystalline and orientational memory phenomena on the isothermal bulk crystallization and subsequent melting behavior of poly(trimethylene terephthalate)

The effects of crystalline and orientational memory phenomena on the subsequent isothermal crystallization and subsequent melting behavior of poly(trimethylene terephthalate) (PTT) were investigated by studying the effect of prior melt‐annealing temperature, T f , on the subsequent isothermal crystallization kinetics, crystalline structure and subsequent melting behavior of neat and sheared PTT samples. On partial melting, choices of the T f used to melt the samples played an important role in determining their bulk crystallization rates, in which the bulk crystallization rate parameters studied were all found to decrease monotonically with increasing T f . The decrease in the values of these rate parameters with T f continued up to a critical T f value (ie ca 275 °C for neat PTT samples and ca 280 °C for PTT samples which were sheared at shear rates of 92.1 and 245.6 s −1 ). Choices of the T f used to melt neat PTT samples had no effect on the crystal structure formed. The subsequent melting behavior suggested that the T f used to melt both neat and sheared samples had no effect on the peak positions of the melting endotherms observed and that the observed peak values of these endotherms for all sample types studied were almost identical. Copyright © 2004 Society of Chemical Industry