An apparent double glass transition of polyphenylene sulfide in blends with polyarylate

Summary Injection molded blends of polyphenylene sulfide (PPS) and polyarylate (PAR) are phase separated as evidenced by transmission electron microscopy (TEM) micrographs and the existence of glass transition temperatures (T_g's) near 100 °C (PPS) and 190 °C (PAR). Upon annealing, blends that contain 15% to 40% by weight PPS exhibited unusual double glass transition temperatures (aside from PAR's T_g at 190 °C) at ca. 88 °C and 110 °C. These transitions coincide, respectively, with the T_g's of amorphous and crystalline PPS homopolymer. PPS crystallinity and average domain size distribution were found to be larger in the skin region than in the core region. It is believed that the double T_g's are brought about by different PPS domains with two types of amorphous material.