Model Epoxy/metal-oxide Chemical Interactions: Diethanolamine on Oxidized Copper and Aluminum

Diethanolamine (DEA), a model compound for an amine cured epoxy resin, was absorbed from dilute ethanol solutions onto air-oxidized Cu, air-oxidized Al and phosphoric acid-anodized Al. The adsorbate/substrate chemical interactions were probed by X-ray photoelectron spectroscopy (XPS). XPS monitoring of DEA coverage on air-oxidized Al as a function of temperature in ultrahigh vacuum shows that significant thermal desorption begins only above 500 K, demonstrating that specific chemical bonding interactions do occur between an amine-cured epoxy and a “real world” oxide surface. DEA desorption temperatures and N ls binding energies are consistent with N tone-pair coordination to acidic aluminum sites. © 1992