EFFECT OF FIBER CONDITIONING ON THE INTERFACIAL SHEAR-STRENGTH OF GLASS-FIBER COMPOSITES

A study of the interaction of water-sized E glass fibres, supplied with and without an aminopropylsilane coupling agent, with vinyl and epoxy resins is reported. Interfacial shear strength measurements, made by means of the multifragmentation technique, have demonstrated that molecularly thin layers are effective adhesion promoters, as indicated by (a) the silane contamination on the nominally non-coupled fibres and (b) the aqueous extraction of the coupled fibres. Epoxy resins adhere through amino coupling reactions, but for the vinyl ester resin the maximum adhesion probably occurs through aluminium hydroxide sites exposed through extractive hydrolysis, and acidic residues in the resin.