(a-4467)ATMOSPHERIC PRESURE PLASMA TREATMENT OF ORGANIC MATRIX COMPOSITES FOR STRUCTURAL ADHESIVE BONDING

摘要

The effect of surface preparation method and adhesive type on the bond strength of carbon-fiber-reinforced bismaleimide composites has been examined. The surface preparation methods included peel ply removal, hand sanding, and atmospheric pressure plasma activation. Bond performance after aging 96 hours and after contamination with A-9 cutting fluid has been studied as well. The adhesive choice has a strong impact on bond performance. For example, the fracture toughness (G_(1C)), as measured by the double cantilever beam method (ASTM D 5528), is 7.2±0.8 psi-in for Cytec FM 300K film adhesive, compared to 10.2±0.4 psi-in for 3M AF 191K film adhesive. Aging decreased the G1C values by about 15 % in both cases. Conversely, the cutting fluid caused the fracture toughness to fall to 4.6±0.4 psi-in for Cytec FM 300K, but had no effect on the joint strength for 3M AF 191K. In all cases, plasma activation after peel ply removal, or peel ply removal and sanding, improved bond performance. This was observed primarily as an increase in cohesive failure mode from about 78 % to 90 % for both adhesives. Plasma activation was also helpful in ameliorating the impact of contamination on fracture toughness.