聚苯醚／聚苯乙烯混合体系玻璃化转变行为的分子量效应

EFFECTS OF MOLECULAR WEIGHT ON GLASS TRANSITION BEHAVIOR OF POLY ( 2 , 6-DIMETHYL-P-PHENYLENE OXIDE)/POLYSTYRENE BLENDS

采用差示扫描量热仪（ＤＳＣ），对不同分子量的聚苯乙烯与聚苯醚的混合体系的玻璃化转变行为进行了较细致的研究。并将实验结果与一些著名的经验和理论方程预示的结果进行了比较（如Ｆｏｘ方程、Ｃｏｒｄｏｎ－Ｔａｙｌｏｒ方程、Ｃｏｕｃｈｍａｎ方程等），从中发现，ＰＳ分子量较高时，混合体系的玻璃化转变温度随混合物组成的变化关系与Ｆｏｘ方程和Ｃｏｒｄｏｎ－Ｔａｙｌｏｒ方程预示的结果相当吻合；当ＰＳ分子量相当低时，玻璃化转变温度随组成的变化关系才与Ｃｏｕｃｈｍａｎ方程的结果接近。

Blends of Poly (2, 6-dimethyl-p-phenylene oxide)and polystyrene of different molecular weight ( (1)NPSL-2 ,(2)NPS-2.(4)NPS-6,(5)NPS-9, in weight ratio of 0 %, 20% . 4v%,50% , 60%, 80% and 100% were prepared from chloroform solution (5 mg/mL) .The solvent was naturally removed in air. The cast films of the blends were dried under vacuum at 85 ± 2℃ for 3 days.For removing all solvent, the films were treated under vacuum at 20￣ 30℃higher than the glass transition temperature of blends for 36 h, respectively. The dependence of the glass transition temperature on the composition of the blends have been studied by DSC technique. It is found that the experiment results w.ere fitted with those obtained from Couchman equation , GordonTaylor equation and Fox equation at different molecular weight, respectively. When the interations.between components are not quite strong, the results of Gordon-Taylor equation are identical with those obtained from Lu-Weisa equation the whole.