THE FIBER-MATRIX INTERPHASE AND THE ADHESION MECHANISM OF SURFACE-TREATED TWARON(R) ARAMID FIBER

In order to optimize the adhesion to an epoxy matrix, Twaron(R) aramid fibre requires a pretreatment with an epoxy/hardener solution. The ch emical composition of the pretreated fibre surface was analysed using X-ray photoelectron spectroscopy and static imaging secondary ion mass spectrometry. To this end model epoxy monomers were synthesized and u se was made of a fluorine-labelled hardener. The effects of processing steps such a's ageing of the pretreatment solution and curing of the epoxy/hardener at the fibre surface have been systematically analysed. Our results show that polar interactions between the aramid and epoxy molecules play a dominant role in the interfacial adhesion mechanism. There is evidence to suggest that the epoxy layer introduced onto the surface of the Twaron(R) filaments is inhomogeneous as a result of th e processing conditions.