Thermal decomposition and kinetics studies on the 2,2-dinitropropyl acrylate–styrene copolymer and 2,2-dinitropropyl acrylate–vinyl acetate copolymer

Abstract

In the present work, kinetics of thermal decomposition of 2,2-dinitropropyl acrylate–styrene copolymer (DNPA/St) and 2,2-dinitropropyl acrylate–vinyl acetate copolymer (DNPA/VAc) was investigated by differential scanning calorimetry (DSC). The influence of the heating rate (5, 10, 15, and 20 °C min−1) on the DSC behavior of the copolymer was verified. The results showed that, as the heating rate was increased, decomposition temperature of the copolymer was increased. Also, the kinetic parameters such as activation energy and frequency factor of the copolymer were obtained from the DSC data by the isoconversional methods proposed by Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO). Average activation energy obtained by KAS and FWO methods for the thermal decomposition reaction of DNPA/St and DNPA/VAc are 157.38 ± 0.27 and 147.67 ± 0.57 kJ mol−1, respectively. The rate constants for thermal decomposition calculated from the activation parameters showed the structural dependency. The relative stability of two copolymers under 50 °C was in this order: DNPA/St > DNPA/VAc. The results of thermogravimetry (TG) analysis revealed that the main mass changes for DNPA/St and DNPA/VAc occurred in the temperature ranges of 200–270 °C. The DSC-FTIR analysis of DNPA/St indicates that the band intensity of nitro and other groups increased haphazardly from 230 °C due to thermal decomposition.