SURFACE AND INTERFACE PROPERTIES OF PLASMA-POLYMERIZED SILICA-LIKE FILMS: PRIMERS FOR STRUCTURAL BONDING

摘要

The results obtained here indicate that chemical reactions occurring at the adhesive/primer interface control the properties of lap joints prepared from aluminum substrates coated with plasma polymerized silica-like primer films. Thus, joints prepared from a 1-part. dicyandiamide-cured adhesive failed cohesively in the adhesive when either a high-hydroxyl or low-hydroxyl primer was used. By comparison, joints prepared from a 2-part adhesive always failed adhesively, near the adhesive/primer interface. These results do not necessarily indicate that hydroxyl content of the primer films is unimportant. Hydroxyl content may have a significant effect on the durability of adhesive joints since primers with high hydroxyl content have lower density and may-allow water to reach the primer/substrate interface more easily than primers with low hydroxyl content. Future work will include using the "stressed durability test" to investigate the durability of lap joints prepared using the same adhesives and primer films considered in this work.