Complex formation and degradation in poly (acrylonitrile-co-vinyl acetate) containing copper nitrate

The pyrolysis of polymers containing metal nitrates may provide a relatively simple, rapid, and advantageous method of producing high-temperature superconductors (HTSCs). The advantage lies in the ability to use conventional polymer processing or microlithographic patterning before pyrolysis. A copolymer of acrylonitrile and vinyl acetate [P(AN-VA)], a well-known fiber-forming polymer, was investigated as a potential HTSC precursor. Complex formation with the highly polar acrylonitrile groups was expected to enhance atomic-level mixing and hinder nitrate recrystallization. The metal nitrates were found to have a profound effect on P(AN-VA) pyrolysis. P(AN-VA) containing copper nitrate (CuN) exhibited complex formation and an exothermic decomposition that began at about 170degreesC (reaction 1-CuN). Reaction 1-CuN had a heat of about 3.5 kJ/g(NO3) and a mass loss of about 0.99 g/g(NO3). As reaction 1-CuN also involved the nitrile groups, it disrupted the nitrile cyclization reaction at about 290degreesC. For a P(AN-VA)/CuN ratio of 2/1, there was no nitrile cyclization, and the thermooxidative degradation temperature was reduced by approximately 200degreesC. (C) 2004 Wiley Periodicals, Inc.