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

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.