Glass fibre coatings based on polyimide–silica hybrids for use in epoxy matrix composites

Despite the advantages that composites have over monolithic materials, their use has been restricted by some deficiencies in their properties. The goal of this study was to overcome deficiencies of unidirectional glass fibre epoxy resin composites by coating the fibres with a "tailored" interlayer. Polyimide–silica hybrids, also known as ceramers, based on hydrolysed tetraethoxysilane and a polyamic acid solution mixture were used to coat glass fibres for epoxy composites. The silica part of these hybrids appears to be present either as dispersed discrete particles or as continuous nano-sized domains trapped within the polyimide matrix. The structure of hybrids determines the final properties. In this study both types of morphologies for the interlayers were utilised to obtain different mechanical, thermal and thermomechanical properties. [Continues.]