PET/LCP共混物的流变行为及其形态

就以不同刚性分子链热致液晶聚合物(LCP)为分散相的聚对苯二甲酸乙二酯(PET)共混物在加工温度范围内的流变性能,共混物熔体经过一系列流场发展起来的形态结构以及它们之间的关系进行了分析。研究表明,PET/LCP共混物为切力变稀的非牛顿流体,共混物熔体的粘度介于两种纯组分高聚物熔体之间,并且各组成的流动曲线于γ=600s～-1时相交;LCP熔体粘度对剪切速率的依赖性比PET熔体大;随着LCP含量增加,共混物的粘流活化能下降;LCP材料性质不同,对共混物流变性能将产生不同的影响。当分散相流体粘度大于基体高聚物的熔体粘度时,分散相很难变形;当分散相流体粘度小于基体时,则分散相的形态发展与加工条件有关。

Rheological Behavior and Morphology of PET/LCP Blends

The rheological behavior and the relationship between the Theological properties and morphology of the PET/ LCP blends are studied. From the flow curves of the blend melts, it is clearly seen that the PET/LCP blends exhibit non - Newtonian behavior and their viscosity values are intermediate between those of the parent LCP and PET. An intersection of the flow curves is at the shear rate of 600 s ~(-1) . Below this shear rate the viscosity of blends increases with the increasing LCP concentration and exhibits lower value than that of the pure LCP. Above 600 s_(-1) , the viscosity decreases with the increasing LCP content and assumes value above that of the LCP. In cases where the LCP is the minor component , the viscosity ratio of the LCP to that of the isotropic polymer is the decisive factor determining the deformation and structure development of the LCP phase. When the viscosity of the suspended phase is lower than that of the suspending one, it is easy for the LCP dispersed phase to develop a fibrillar morphology.