THE MOLECULAR STRUCTURE OF IMIDAZOLE DERIVATIVES ON COPPER (EPOXY RESIN)

The molecular structure of imidazoles on copper and copper oxide, thermal stability of imidazoles on copper, and the chemical reaction of epoxy resin with imidazole-treated copper are studied in order to understand molecular mechanism of anticorrosion and adhesion promotion. Fourier-transform infrared reflection-absorption spectroscopy is used to observe the structural change of imidazole films on substrates. Imidazoles show flat orientation on gold and random orientation on copper. The imidazole rings cleave and the alkyl substituents are eliminated upon heating in air on copper. Different carbonyl groups are produced followed by the appearance of the nitrile group in the final oxidation stage. The difference in morphology and orientation of 2-undecylimidazole on oxide is mainly due to the reactivity of the imidazole and the substrate surface. The degration is catalysed by two types of copper, copper in the film and from the substrate. The rate determining step of the degradation is the reactivity of the carboxylic acid produced in the intermediate step of the degradation and the surface oxide. The inner layer of the deposited film on the slightly preoxidized copper showed a semi-crystalline structure as revealed by chemical depth profile. At elevated temperatures in the range of 150-180(DEGREES)C, production of 4(5H) undecylimidazolone was postulated near the substrate/imidazole interface as initial oxidation compounds. Alkylimidazole copper (II) complexes are synthesized to model the complexes on copper. The difference in oxidation between imidazoles on copper and synthesized imidazole complexes are due to the catalytic effect of the copper ion migrating from the copper substrate and different morphological structure. An epoxy resin shows an appreciable amount of polymerization on the imidazole complex/copper at 100(DEGREES)C. The thickness of the epoxy coating is increased while the imidazole complex dissolved into the bulk resin above this temperature. However, only a small amount of epoxy resin remains on the copper at elevated temperatures.