Reflection-absorption FT-IR studies of the specific interaction of amines and an epoxy adhesive with GPS treated aluminium surfaces

Aluminium surfaces were silanised with γ-glycidoxypropyltrimethoxysilane and the silane films were then further treated with different amines. Investigation before and after treatment, using reflection-absorption FT-IR spectroscopy, strongly indicated that a chemical reaction between the amines and the silane films took place, as observed in the intensity reduction of the epoxy band at 910 cm−1. Increased SiOSi crosslink density was also observed. Treatment with dicyandiamide also showed the appearance of a band which was assigned to the formation of a covalent bond between the curing agent and the epoxy ring of the silane. The results partly explains the improved durability of GPS treated aluminium surfaces after bonding with one-component epoxy adhesives.