Microstructure formation in polyblends containing liquid crystalline polymers

摘要

The performances of multiphase polyblends are greatly affected by their microstructure, while the formation of this microstructure strongly depends on the processing conditions. Being called in-situ composites, polyblends containing thermotropic liquid crystalline polymers (TLCP) have attracted more attention in recent years. On this subject, almost all aspects involved, e.g. rheology, morphology, crystallization, thermal stability, compatibility and mechanical properties of these blends have been studied. Among them, of importance is the formation of fine fibrils having large aspect ratios, which can play the role of reinforcement in the resultant products. However, as shown by the results in literature up to now, not all the combinations of LCP and isotropic polymers can be extruded to form a microstructure in which LCP has the form of long fibrils. It should be known how LCP fibrils are generated in the molten matrix, and what are the conditions for LCP fibril formation. As one part" of our systematic study on the morphology formation of polyblends containing LCPs, this paper will describe the processes involved in the microstructure formation during extrusion and discuss their contribution to the final structure of the extrudate as well.