Although there are many studies on the multiple melting behavior of polyphenylene sulfide (PPS) homopolymer, similar investigations on PPS component in PPS blends with thermoplastics are relatively rare. In the present paper, the multiple melting behavior of PPS blends with polyamide 6 (PA6) have been investigated by differential scanning calorimetry (DSC). The double melting peaks are also observed for PPS in the blends. Although the annealing temperature and time as well as the heating rate of DSC scanning are different, the lower melting peak temperature of PPS in the blend is higher than that of pure PPS and the higher melting peak temperature is lower than that of pure PPS. It is suggested that PA6 can accelerate the cold‐crystallization of amorphous PPS due to the possible presence of interfacial interaction between the component polymers to induce the heterogeneous nucleation, and increase the perfection of PPS crystals. The multiple melting behavior of PPS in the blends are explained by recrystallization. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1579–1585, 2000

A systematic study of the effect of physical ageing and cooling rate on a-relaxation peak are carried out in PVC. It was said that a-peak and Tg are not the same concept. Both are closely connected with amorphous state, but show different behaviours in the same pre-treatment conditions: varying physical ageing time in sub- Tg or changing cooling rate from Tg + 20℃ to room temperature . Some interesting results were obtained as follows:When Tg lowers with increacing ageing time or decreacing cooling rate, a-peak temperature (Tα) keeps constant. On the other hand, the intensity of the a-peak decreases. This behaviour shows that a- relaxation peak is not a typical linear anelastic internal friction peak, as there is a quenching peak added on it.A detail discussion will be given in this paper.