Thermal decomposition and kinetics studies on the poly (2,2-dinitropropyl acrylate) and 2,2-dinitropropyl acrylate–2,2-dinitrobutyl acrylate copolymer

Abstract

Thermal stability and decomposition kinetics of two energetic binders: poly (2,2-dinitropropyl acrylate) (PDNPA) and 2,2-dinitropropyl acrylate–2,2-dinitrobutyl acrylate copolymer (DNPA/DNBA) were investigated by thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques under nitrogen atmosphere. The results of TG analysis revealed that the mass loss about 60 % of two energetic binders occurs in the temperature ranges of 200–280 °C. Meanwhile, the decomposition temperature of PDNPA and DNPA/DNBA started at 183 and 198 °C, respectively. The decomposition kinetics of two energetic binders were studied by non-isothermal DSC under various heating rates (2.5, 5, 7.5, 10 and 12.5 °C min−1). The kinetic parameters for thermal decomposition of the both binders, such as activation energy and frequency factor, were obtained by ASTM E698, Kissinger–Akahira–Sunose (KAS) and Starink methods. The activation energy values obtained by KAS and Starink methods increase with the degree of conversion (α). The activation energy of thermal decomposition at α = 0.1 obtained by Starink and KAS methods for the PDNPA and DNPA/DNBA are 123.23 ± 0.13 and 127.71 ± 0.12 kJ mol−1, respectively. The rate constants for thermal decomposition calculated from the activation parameters showed the structural dependency. The relative thermal stability of two polymers under 50 °C was in this order: DNPA/DNBA > PDNPA.