In situ composites: Effect of elongational flow velocity on thermotropic liquid crystalline co-polyester fibrillation in thermoplastic/TLCP systems

This study focuses on the TLCP fibrillation process in a thermoplastic (PP) matrix during melt blending. The process of blending includes a single extrusion process in a twin-screw extruder with compatiblization and injection moulding of the extrudates. The TLCP, VA950 in situ fibrillation, compatiblization with PP and retainment of fibrils in the injection-moulded samples has already been achieved in our earlier study. However, the fibrillation process remains a complex issue. There are many factors like viscosity ratio, capillary number, composition, and flow speed which will affect the fibrillation. The elongational flow seems to be a more important factor affecting the TLCP fibrillation. The present study aims to identify the important factors which influence the TLCP fibrillation at their near-critical conditions. The morphological features and mechanical properties show that the compatiblization and elongational flow speed are very important for effective fibrillation. © 2001 Elsevier Science Ltd. All rights reserved.