Complex formation and degradation in poly(acrylonitrile-co-vinyl acetate) containing metal nitrates

Polymers containing metal-nitrates have been proposed as advantageous precursors for high temperature superconductors such as yttrium-barium-copper-oxide (YBCO). The advantage lies in using conventional polymer processing such as fiber spinning or microlithography before pyrolysis. This research investigated complex formation and degradation in poly(acrylonitrile-co-vinyl acetate) (P(AN-VA)) containing either yttrium nitrate (YN) or barium nitrate (BaN) and follows a similar investigation for copper nitrate. Complex formation was observed in P(AN-VA)/YN but not in P(AN-VA)/BaN. The exothermic nitrate degradation below the P(AN-VA)) cyclization temperature involved the release of NO3, a reaction with the nitrile group that disrupted cyclization, and, for BaN, P(AN-VA) degradation. For a P(AN-VA)/nitrate ratio of 2/1 there was no cyclization and the degradation temperature was reduced by about 200 °C. The pyrolysis of P(AN-VA)/BaN yielded largely BaCO3, which is likely to impede the formation of YBCO.