Spectroscopic and mechanical evidence of the influence of the substrate on an anaerobic adhesive cure

The catalytic effect of different substrates-steel, aluminium and copper-on the curing reaction of a standard anaerobic adhesive is investigated by infrared microscopy in reflection mode. Thus, kinetics of the cure reaction, studied from the decrease of the carbon-carbon double bonds absorption peak, are quite different depending on the substrate under investigation. Among the studied metals, copper has been found as the most reactive surface. The assumed role of saccharine contained in the anaerobic adhesive which is able to oxidise metals into ions will be highlighted. Finally, an attempt will be made to correlate the kinetic results with the mechanical performances of the adhesive joint measured by a single lap shearing test. Thus, fast curing reaction of the anaerobic adhesive on a surface such as copper leads to poor maximal strain while lower surface reactivity may provide better mechanical performances of the adhesive joints. (C) 1997 Elsevier Science Ltd.