ABSTRACT
Twaron aramid fibres require a surface treatment process in order to optimize their adhesion to polymer matrix systems. In this process, a finish containing epoxy reaction products is applied to the fibre surface and subsequently heat treated. The resulting fibre surface yields improved interfacial adhesion to, for example, epoxy and rubber matrices. In order to assess the role of the chemically and topographically modified fibre surface, detailed analysis of the interphase is a prerequisite. Well-defined starting materials and model components combined with surface analysis techniques are used. The reaction products in the epoxy-based finish are determined using a model formulation. The reaction chemistry, referred to as ‘maturation’ of the finish, and its relationship to an important process parameter, the pH of the formulation, is established. Quantitative information on the dimensions and the chemical composition of the interphase, the presence of functional groups at the fibre surface and the correlation between the interphase structure and the measured adhesion level to an epoxy matrix is studied.
