TLCP/PEI共混体系的流变特性与结构关系的研究

研究了VectraA950/PEI共混体系多层次结构与共混体系动态流变特性的关系.在研究液晶高分子的动态流变特性时,引入Palierne模型对动态实验结果进行预测.结果表明,TLCP分散相在高频时偏离了球形,导致Palierne模型拟合的结果与TLCP/PEI共混体系的实验结果在高频时不吻合.这与VectraA950/PEI共混体系中多层次结构在动态流场中的流变响应有关:在频率偏高时,液晶高分子取向不能完全松弛,易于形成各向异性结构,在流场作用下,易产生大形变;由于液晶高分子液滴的回缩过程很慢,在频率偏高时,产生的大形变不易回复,所以保留了纤维结构.

Relationship Between Rheology Behavior of TLCP/PEI Blend System and Its Multi-scales of Structur

Structural rheology of multi-scales of Vectra A950/PEI blend was studied. The prediction of the dynamic rheological behavior of Vectra A950/PEI blend according to Palierne model is consistent with the experiment results during the period of low frequency, while at high frequency, the prediction is deviated from the experiment results. The cause is that dispersed phase is deviated from sphere at a high frequency, which is related to rheological response of multi-scales of structure. The explanations are: (1) at the higher frequency, molecules orientation of Vectra A950 is hard to relax completely, and global anisotropy appears, so that the dispersed TLCP particles are easy to be deformed; (2) the relaxation process of dispersed phase droplet is slow, therefore, the deformed dispersed TLCP droplets are not able to retract at the high frequency. Affected by the two factors metioned above, Vectra A950 droplets in Vectra A950/PEI blend are deviated from sphere, resulting in different structural rheology properties from flexible polymer blends.