Adsorbed metal ions as stabilizers for the thermal degradation of polyacrylamide

Abstract

The thermal degradation of polyacrylamide has been studied in the presence of various metal ions using thermogravimetry. The thermal decomposition of the polymer in general occurs at higher temperatures in the presence of metal ions than with the pure polymer. Empirical measures of the stabilizing effect of the metal ions have been made by determining the temperatures of 12% and 50% decomposition, and the integral procedural decomposition temperature (IPDT). For main group metal ions, the stabilizing effect, as measured by the difference in ipdt between polymer-metal complex and copolymer, was inversely proportional to the radius of the metal ion, suggesting that the strength of the complex between the ion and polymer is important in determining stability. Transition metal ions, in contrast, showed no simple dependence of stabilizing effect on ionic radius, but showed, instead, a dependence upon the ligand field stabilization energy.