Adhesion between aluminum and copolymers of ethylene and vinyltrimethoxysilane

Abstract The adhension between aluminum and poly(ethylene‐co‐vinyltrimethoxysilane) (EVS) and poly(ethylene‐co‐butylacrylate‐co‐vinyltrimethoxysilane) (EVSBA), respectively, have been studied. For comparison an ordinary low density polyethylene (LDPE), a poly(ethylene‐co‐butylacrylate) (EBA), and an ionomer regarded as a bonding polymer were studied as well. The peel strength of laminates obtained by pressing were measured by a T‐peel test. The structure of the fracture surfaces were investigated by reflection‐IR, ESCA, and SEM. The peel strength of the LDPE and the EBA samples were 100 and 700 N/m, respectively. Although the amount of vinylsilane was low, about 0.2–0.3 mol %, its presence had a pronounced influence on the adhesion: 1800 and 3000 N/m for EVS and EVSBA, respectively. This is even higher than the value observed for the ionomer, 1560 N/m. Although there was a marked difference in surface topology, the SEM and ESCA analysis showed that the fracture was cohesive for both EVS and EVSBA. Immersion in water at 85°C increased the peel strength even more, especially in the case of EVSBA (up to 9000 N/m), in contrast to what is normally observed with aluminum polyethylene laminates. The results suggest that strong and nonhydrolyzable bonds, e.g., covalent bonds, have been formed across the polymer‐metal interface for the ethylene copolymers containing vinylsilane.