Metallization of cross-linked epoxy resins by reduction of polymer-incorporated metal ions

The metallization behavior of the poly(ethylene glycol) diglycidyl ether films cured with 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride (DMCDA) by reduction of polymer-incorporated cobalt chloride or nickel chloride was investigated by means of infra-red spectroscopy, dynamic viscoelastic measurement, X-ray photoelectron spectroscopy, scanning electron microscopy and electron probe microanalysis. For the film containing the metal chloride cured at finally 200 °C for 5 h, the metal ion was homogeneously distributed in the inner part of the film, except that the film surface at the air side had a higher metal ion concentration because of the chelation of the metal ion with carboxylic acid group generated by the reaction of DMCDA with water in air. By the reduction treatment in aqueous sodium borohydride at 20–50 °C, the metal ion migrated to both sides of the film and then reduced to pure metal. The metal layer generated at the air side was thicker than the one at the side of a polypropylene plate used in the preparation of film. The X-ray diffraction analysis of the reduced films revealed that the generated cobalt and nickel were almost amorphous.