Modifications of polyimides and polyimide–inorganic oxide hybrids with perfluoroether oligomers for use as matrices for carbon-fibre composites

The performance of a polyimide derived from a low molecular weight polyamic acid (Skybond 703) and the corresponding polyimide–silica hybrids, used as matrices for Carbon-fibre composites, was evaluated. The study involved the incorporation of telechelically modified perfluoroether oligomers into the resin systems. Telechelic modifications of the hydroxyl-terminated perfluoroether oligomer were carried out in order to achieve the required compatibility with the polyimide phase through grafting reactions with the polyamic acid precursor. In the case of hybrids, the compatibility requirements were extended also to the prehydrolysed alkoxysilane solution added to the polyamic acid mixtures. The latter was achieved with the incorporation of a silane coupling agent (γ-glycidyloxypropyltrimethoxysilane), which resulted in the formation of nano-scale silica domains in the polyimide. [Continues.]