Effect of an aminosilane on the cathodic delamination of adhesive bonds between neoprene and steel

Cathodic delamination of adhesive bonds between neoprene and steel during immersion in 3.5% artificial sea water (ASW) at a potential of -1.42 V vs. SCE was investigated. Joints prepared using a commercial adhesive and primer delaminated at a much faster rate than those prepared using the same adhesive but with γ-aminopropyltriethoxysilane (γ-APS) added to the primer. X-ray photoelectron spectroscopy (XPS) was used to examine the failure surfaces and it was determined that failure was always near the primer/oxide interface. Zinc was detected on the failure surfaces of joints prepared using the commercial primer but not on those of joints prepared with the modified primer. Nitrogen was detected on the failure and fracture surfaces of joints prepared using the modified primer but not on those of joints prepared using the commercial primer. The nitrogen was present as both free amine and protonated amine formed by reaction of γ-APS with the hydrochloric acid evolved from chlorinated rubber in the primer duri...