USE OF THE INVERTED-BLISTER TEST TO STUDY THE ADHESION OF PHOTOPOLYMERS

The adhesion of photopolymers to glass fibre-reinforced plastic (GFRP) circuit-board materials has been evaluated using an 'inverted-blister' test method. This test method is a development of the conventional blister test and modifications were found to be necessary to prevent cohesive failure of the thin photopolymer film prior to delamination from the GFRP substrate. In the 'inverted-blister' test method the relatively delicate photopolymer film is firmly bonded to a rigid support and the GFRP substrate is pressurized to form the blister. This overcomes the problem of cohesive failure of the photopolymer film prior to interfacial delamination. The data obtained have been analysed using a fracture mechanics approach, although it was found necessary to use an analysis which also modelled the residual stresses present in the photopolymer/GFRP laminate. It is shown that the determination of the adhesive fracture energy, Ga, does indeed provide a geometry-independent measure of the delamination resistance of the photopolymer/GFRP interface. © 1990.