Effect of curative in hydroxyl-terminated polybutadiene-based binder system on characteristic properties and kinetics of polymer-based energetic composite

A series of polymer-based energetic composites (PEC) comprising 90% (by wt.) of crystalline octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) filler and 10% (by wt.) of hydroxyl-terminated polybutadiene (HTPB)-based binder system cured with different curing agents were prepared by cast cured technique. The effects of HTPB-based binder cured with different curing agents on the characteristic properties were investigated through different analytical and instrument techniques. The chemical stability was studied through vacuum stability tester apparatus at 100°C for 40 h. The results show that all energetic composites are chemically stable and compatible with each other. The results indicate that there is considerable variation in the impact and friction sensitivity with varying of the curing agents in the HTPB-based binder system. Thermogravimetric (TG) and differential scanning calorimetry measurements show that the thermal stability does not depend on the curing agents used. The detonation study outcomes show that the detonation performance of the composites is quite different, depending on the types of the curing agents used. The kinetic parameters for thermal decomposition were studied through the TGA methods at multiple heating rates by using the kinetic Ozawa, Kissinger, and Kissinger–Akahira–Sunose (KAS) methods. The PEC/TDI, PEC/IPDI, PEC/MDI, and PEC/TMDI samples showed average activation energies of 236.5, 208.7, 192.8, and 250.3 kJ/mol, respectively. These values are consistent and comparable to those obtained from other kinetic methods. However, the activation energy varies with varying the curing agent used in HTPB-based binder system.