Some hygrothermal effects on the mechanical behaviour and fractography of glass-epoxy composites with modified interface

Abstract

The mechanical behaviour of glass fibre-reinforced epoxy composites with introduced layers of materials and with fibre coating is studied. The role of aerosil powder as a filler material is investigated, and the fracture mode is analysed by scanning electron microscopy. The investigation shows a considerable drop in interlaminar shear stress for the higher fibre volume fraction, whereas the introduction of filler materials to the composite causes no change. Surface mat-reinforced samples show a marginal increase in shear stress. Exposure to moisture reduces the interlaminar shear stress value faster for the higher fibre volume fraction, thereby highlighting the role of the interfacial area. Impact values for coated and uncoated fibres show an identical trend with exposure to dry heat, the former always recording lower values. The impact value decreases faster with moisture absorption for the composite with the higher fibre content. Fractography reveals poor adhesion in the coated laminates. © 1991 Chapman & Hall.