The melting behaviour of polyphenylene sulfide (PPS ) and its blends with bisphenol A polysulfone (PSF ) and polyetherketone with cardo side groups (PEK-C ) are investigated with DSC technique. It is found that with a rise in melt temperature

Tmelt

and melt time

tmelt

the lower temperature melting peaks increase while the upper ones decrease and disappear in some cases

which can be attributed to the obstructive effect of branching or crosslinking of PPS on the crystallization of PPS at higher temperature. As annealing crystallization tempera-ture increases

not only the peak temperature of the lower melting peaks shifts to higher temperature

but also their intensity increases. PSF and PEK-C have noeffect on the lower melting peaks of PPS but are unfavorable to the crystallization of the higher melting species Tmelt and tmelt exert greater influence on the double melting behaviour of PPS in the blends in comparison with neat PPS.