Polymer-matrix Composites for High-temperature Applications

Abstract

Over the last decade, applications of fibre-reinforced composites using polymer matrices have seen tremendous growth. In spite of the complexity of their behaviour and the unconventional
nature of fabrication and other aspects, the usage of such composites, even for primary loadbearing structures in military fighters and transport aircraft, and satellites and space vehicles has been beneficially realised. Most of such usage constituted structural applications (such as in airframe) where service temperatures are not expected to he beyond 120 'C. Attention is now focussed on expanding the usage of such composites to other areas where temperatures could be higher-in the range 200400 "C. The intended applications are structural and non-structural parts on or around the aero-engines and airframe components for supersonic or hypersonic aircraft. The development of polymer matrices-such as bismaleimides, polyimides, cyanates, and liquid crystalline polymers and others-has brought such applications within the realm of practicability. The associated problems have been in terms of suitable processing technologies and in balancing the requirements of the performance with those of the processing. This paper describes briefly such developments and reviews the potential application scenario.