序列结构对苯乙烯/丁二烯共聚物热释电流峰的影响

本文研究聚合方式对苯乙烯/丁二烯共聚物热释电流峰(TSC)的影响。共聚物试样有三个电流峰(β、α和ρ峰)。实验结果表明:聚合方式对β峰(丁二烯局部运动)基本没有影响,但对α峰(丁二烯相的T_g转变)的位置有明显的影响,而且两步法试样有两个α峰;嵌段共聚物试样在高温还有一肩部(苯乙烯相的T_g转变),无规共聚试样没有肩部。由共聚物的序列结构能圆满解释TSC结果,而序列结构决定于聚合方式。因此,本工作将苯乙烯/丁二烯共聚物的序列结构与性能联系起来。

EFFECT OF SEQUENCE STRUCTURE ON THERMALLY STIMULATED CURRENT PEAKS OF STYRENE/ BUTADIENE COPOLYMER

The thermally stimulated current method (TSC) has been used to study the relaxation behavior of styrene/butadiene copolymers. All copolymers exhibit three current peaks which are labeled designated as β, α and p peak in the order of increasing temperature. The experimental results show that polymerization method markedly influences the position of the peak resulting from glass transition of polybutediene phase.Moreover, the specimen obtained from two-step polymerization exhibits two a peaks. In addition, there is a shoulder for the segmented copolymer, while there is no shoulder for the random copolymer. The TSC result can be explained with the sequence structure which depends on the polymerization method.