Enhancing the thermal decomposition of composite modified double base propellant using Al/hematite and Al/hematite/graphene thermites

In this study, Al/hematite and Al/hematite/graphene-nanosheets (GNS) thermites are successfully prepared through a blending and sonication method. These thermites are then employed as catalysts to enhance the thermal decomposition of an ammonium perchlorate-based composite modified double base propellant (AP-CMDBP) prepared by blending double base propellant (DBP), polyurethane (PU) and ammonium perchlorate (AP). The catalytic effect of the synthesized thermites on the thermal decomposition of AP-CMDBP is investigated by relevant thermal characterization techniques (thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC)). The decomposition kinetic is also assessed in order to evaluate Arrhenius parameters for the studied systems (AP-CMDBP, AP-CMDBP-Al/hematite, and AP-CMDBP-Al/hematite/GNS). The DSC results indicated that both Al/hematite and Al/hematite/GNS thermites accelerate the thermal decomposition procedure and enhance the total heat released from AP-CMDBP. Compared to Al/hematite, Al/hematite/GNS highlights a significant decrease in AP-CMDBP exothermic decomposition peak temperatures (from 206.8 to 201.3 °C for the first peak and from 387.5 to 342.4 °C for the second one). Additionally, lower values of the activation energy (Ea) (159.15 and 96.71 kJ/mol) are obtained when Al/hematite/GNS thermite is added to the AP-CMDBP formulation. This demonstrates a higher catalytic effect of Al/hematite/GNs than the other thermite. Based on these findings, the combination of Al/hematite thermite and GNs showed a synergetic effect on the catalytic decomposition of AP-CMDBP, giving rise to a potential cost-effective combustion catalyst for AP-based composite modified double base propellants.