Influence of γ-radiation on thermal destruction of a cross-linked acrylic polymer

Abstract

The effect of γ-radiation dosage on the thermal stability of the cross-linked acrylic polymer "Carbomer-140" (СRB) was investigated. The DTA, TGA, and DTG curves show multistage processes occurring in different temperature ranges on heating CRB from 25 °C to 500 °C. The rates of thermal decomposition of CRB were determined in the temperature ranges of 40–110 °C, 180–260 °C, 260–330 °C, and 330–500 °C. In combination with results of electronic structure calculations, potential thermal destruction reactions were proposed for the indicated temperature ranges. The main reactions for thermal decomposition of CRB are formation of ketones and cyclic anhydrides with formation of unsaturated bonds in the macromolecule due to elimination of H2O, CO2, and CO, respectively, from the polymer chain. An increase in the radiation dose applied to CRB leads to a decrease in the post-radiation thermal stability of the polymer. During radiolysis, double bonds are formed and accumulate in the polymer, contributing to the thermal destruction of CRB. As a result, the higher the radiation dose, the higher the rate of post-radiation thermal destruction.