PMMA/α-MSAN共混体系长时弛豫区域的时温叠加失效与相分离的关系

Relationship Between Breakdown of Timetemperature Superposition Principle and Phaseseparation for PMMA/MSAN Blends

通过考察聚甲基丙烯酸甲酯（ＰＭＭＡ）／聚（α－甲基苯乙烯丙烯腈）（α－ＭＳＡＮ）共混体系动态粘弹函数的时温叠加，发现在终端区域时温叠加失效与其相分离有关．相分离使得终端区域的动态储能模量Ｇ′（或动态损耗模量Ｇ″）与频率的关系［ｌｇＧ′（ｌｇＧ″）～ｌｇω］明显偏离经典粘弹模型．随组成的改变，时温叠加的失效呈现温度依赖性，其“失效温度”（Ｔｄ）可很好地表征ＬＣＳＴ类共混物的相分离，而且在用其表征相分离时。

By examining superposition of viscoelastic functions of poly(methyl methacrylate)(PMMA)/poly(methylstyrenecoacrylonitrile)(MSAN) blends, we found that breakdown of timetemperature superposition principle in the long time relaxation region(terminal region) is related to phaseseparation of this blends. Heterogeneity in the blends results in the relationship between dynamic storage modulus G(or dynamic loss modulus G) and frequency in the terminal region no longer obey the model of linear viscoelasticity. It is interesting that there exists temperature dependence of this breakdown. This breakdown temperature(Td) can be used as a criterion for phaseseparation of the blends and was considered superior to socalled critical temperature(Tb) obtained by plotting of lgG vs. lgG.