Thermal degradation of poly(acrylic acid) containing copper nitrate

A high temperature superconductor (HTSC) precursor containing a polymer and metal nitrates may be processed with relative ease before pyrolysis. This article focuses on the thermal decomposition of poly(acrylic acid) (PAAc) containing copper nitrate (Cu-N) as a first step in the study of an HTSC precursor containing copper, barium and yttrium nitrates. The degradation of PAAc/Cu-N was found to be a complex multi-stage process that was not always directly related to the degradation of the individual components. Adding Cu-N to PAAc causes a dramatic decrease in thermal stability. While the degradation of PAAc in argon yields a carbonaceous residue, no such residue was found for the degradation of PAAc/Cu-N in air. The rate of PAAc/Cu-N degradation is significantly higher in air than in argon. The decomposition mechanisms include polymer chain scission catalysed by copper ions and the formation of terminal macroradicals that generate low molecular weight organic compounds. (C) 2004 Elsevier Ltd. All rights reserved.