聚甲基丙烯酸甲酯/聚(苯乙烯-丙烯腈)共混体系相分离的特征动态流变响应

Characteristic Dynamic Rheological Response to Phase Separation for Poly(methyl methacrylate)/Poly(styrene-co-acrylonitrile) Blends

采用动态流变学方法，结合小角激光光散射（SALLS）测定，对聚甲基丙烯酸甲酯（PMMA）／聚（苯乙烯－丙烯腈）（SAN）共混体系的动态流变行为与相分离的关系进行了研究．发现在低频区域，时温叠加失效与共混物体系发生相分离有关，时温叠加失效温度Tb 与用SALLS测定的浊点温度Tc一致，用低频区域动态储能模量G’与频率 的关系[1gG’～lg（ αT）] 偏离线性粘弹模型或时温叠加失效温度表征PMMA／SAN共混体系的相分离是有效的．

Abstract On the basis of phase separation temperatures (Tc) for poly (methyl methacrylate )/poly-(styrene-co-acrylonitrile) (PMMA/SAN) blends with different compositions, measured by small angle laser light scattering (SALLS), we have studied the dynamic rheological behavior of these blends at various temperatures below, near and above Tc. The results showed that the time-temperature superposition principle could be applied and the linear viscoelastic response emerged in the terminal region at temperatures below Tc. However, it was found that the breakdown of time-temperature superposition principle appeared, and viscoelastic response was deviated from the linear behavior in the terminal region at temperatures near and above Tc.