Processing and properties of a fibre reinforced liquid crystalline polymer

The unique processing and rheological behaviour of filled LCPs are not fully understood, since they are highly sensitive to thermal and flow histories. In this work, extrusion and rheological studies of a thermotropic liquid crystalline polymer reinforced with short glass fibres were carried out using a capillary rheometer. Attempts have been made to correlate the processing conditions with the structure and properties of the extrudates. Microscopic analysis has shown that the glass fibres were mostly oriented in the direction of extrusion and the presence of voids is evident in the extrudates. Good-quality extrudates were generally obtained, although melt fracture occurred in some extrudate as revealed by scanning electron micrographs. The mechanical properties, in particular the fracture stress, strain and Young's modulus of the materials, were found to be related closely to the rheological histories and the processing conditions.