两个不同分子量聚苯乙烯混合体系的玻璃化转变

On the Glass Transition of Binary Blends of Polystyrene with Different Molecular Weight

用差示扫描热量法测定了两个分子量不同的聚苯乙烯混合体系的玻璃化转变温度随组成的变化，并与Ｆｏｘ方程，Ｇｏｒｄｏｎ－Ｔａｙｌｏｒ方程和Ｃｏｕｃｈｍａｎ方程的预测结果进行了比较，以验证这些经验方程的适用性。

Blends of polystyrenel(Mw/Mn=1.15,Mw=8. 59 × l02 )and polystyrene-2(Mw/Mn=1.06,Mw=1. 29× 104)in weight ratio of 0,20,40,50,60,80 and 100%were preparedfrom benzene solution. The cast films of the blend were dried under vacuum at 35℃,40℃,55℃,65℃, 75℃ ,105℃,and 130℃ for 2 days, respectively. The dependence of the glasstransition temperatures on the composition of the blends have been studied by DSC tech-nique. It is found that the experiment results were not fitted with those obtained from theFox, Gordon-Taylor, and Couchman equations. It appears that the parameter k(or △Cp2/△Cp1)in the mentioned equations, which only refers to the difference in heat capacity of thepolymer before and after transition, is not reasonable.