ADHESIVE BONDING OF FIBER-REINFORCED COMPOSITES

The applicability of test methods for adhesive-bonded metal adherends to fibre-reinforced composites is considered Bond strengths obtained by methods chosen as suitable are compared The most critical factor in metal joints is the pretreatment of the adherend before bonding, as this controls the structure and chemistry of the oxide surface and hence durability in hot-humid conditions, often with little effect on initial strengths. For fibre-reinforced epoxy resin adherends, the critical factor is the initial bond. Initial bond strength, measured by any method, is related to the presence of contaminants on the adherend surface. Loss of strength in hot-humid conditions is related to water absorption by adhesive and matrix and not to reduced adhesion. Thermoplastic-matrix composites require pretreatments which increase their surface energy and wettability by adhesives.