Filament winding of bicomponent fibers consisting of polypropylene and a liquid crystalline polymer

This paper is concerned with novel wholly thermoplastic composite materials suitable for use in filament winding. Bicomponent fibers consisting of a s heath of polypropylene (PP) of lower melting point and a core of a thermotr opic liquid crystalline polymer (TLCP) of higher melting point were produce d in a ratio of 30/70(w/w) using a modification of a standard bicomponent s pinning process. The modifications were required to handle the necessity of melting the TLCP at a temperature in the range of 320 degreesC while not r aising the temperature of PP above 300 degreesC which would lead to signifi cant degradation of PP. The tensile modulus and strength of the fibers were 38.7 GPa and 465 MPa, respectively, A methodology was developed for establ ishing the conditions for filament winding these bicomponent composite fibe rs, which would allow adequate consolidation without disrupting the molecul ar orientation within the TLCP component and hence reinforcing properties. Cylinders and rings were generated with winding angles of 90 and 80 degrees C under conditions in which the PP was melted but the TLCP retained its pro perties. The degree of consolidation was evaluated using the interlaminar s hear strength test and optical microscopy. Because of the uniform distribut ion of the reinforcing component there was no failure observed in this test . The void content was determined to be 5.2%. The tubes generated from thes e materials have the potential for transport liquid oxygen and corrosive fl uids. (C) 2001 Elsevier Science Ltd. All rights reserved.