INFLUENCE OF FIBER REINFORCEMENT ON THE MECHANICAL ANISOTROPY OF LIQUID-CRYSTAL POLYMERS

An evaluation of stiffness, toughness and strength has been performed on four materials based on thermotropic liquid crystalline polymers. These were of two different chemistries, with and without 27 wt% of short glass fibre. The change in chemistry had little effect on the stiffness properties, but the addition of glass fibre reduced the in-plane stiffness anisotropy. Laminate modelling was performed in an attempt to reproduce this. Fracture toughness also showed considerable anisotropy, both with and without glass, in the nature of the fracture surface and values obtained. Under long-term loading, the unreinforced material delaminated more severely than the glass fibre reinforced system, and also showed a transition in behaviour on dynamic loading.