The effectiveness of thermal treatment for development of conductive metalized aramid fiber using supercritical fluid carbon dioxide—Fiber-metal adhesive strength improvement

The effect of thermal treatment to improve the metal adhesion into poly-(p-phenylene terephthalamide) (PPTA), e.g. aramid fiber, has been investigated. After palladium(II)-hexafluoroacetylacetonate metal complex, Pd(hfac)₂, seeding into the fiber using supercritical fluid carbon dioxide, scCO₂, a post-thermal treatment was conducted. As a result, after carrying out electroless copper plating, the adhesive strength between polymer substrate and copper layer greatly increased. Also, in order to have a better comprehension on decomposition reactions of Pd(hfac)₂ under supercritical conditions, remains of metal complex were analyzed using electron ionization mass spectrometry technique (EI-MS). EI-MS mass spectra derived from Pd(hfac)₂ gave us useful information about its dissociation reactions and reaction temperature under supercritical conditions. Additionally, to verify the Pd particles seeding in the fiber surface, X-ray photoelectron spectrometry (XPS) analyses were performed. The results confirmed that post-thermal treatment induced Pd particles diffusion and deeper penetration of Pd complex and its fragments into the fiber.