SURFACE PRETREATMENT OF GLASS-FIBER-REINFORCED LIQUID-CRYSTALLINE POLYMER COMPOSITES BY EXCIMER-LASER FOR ADHESIVE BONDING

This paper reports the results of using a new laser surface pretreatme nt technique to improve the strength of adhesive joints. A high power KrF excimer laser at 248 nm output was used to surface-treat a glass f iber-reinforced liquid crystalline polymer (LCP) composite. With optim um process parameters, the polymer matrix at the surface was etched aw ay efficiently and the bare fibers anchored on the matrix were left da ngling and undamaged. The surface morphology produced by this new tech nique resulted in high quality adhesive joints. Both lap-joint and but t-joint configurations were investigated. A 350% improvement in the bu tt-joint strength was achieved by this new pretreatment technique as c ompared with that of the untreated one.