Insight into graphene-salen metal nanocomposites on combustion performance and mechanism of HMX-CMDB propellant

A series of novel graphene-salen metal nanocomposites with different active metals and molecular structures were designed, synthesized and characterized using SEM, EDS, FTIR, XPS and RAMAN instruments. Effects of the as-synthesized graphene-salen metal nanocomposites on the combustion performance and mechanism of HMX-CMDB propellant were studied. Among the nanocomposites considered, S-792-Ni has the best effect on the combustion performance of HMX-CMDB propellant, which makes the propellant possess high burning rate, low pressure index and good combustion stability. The excellent combustion performance of HMX-CMDB propellant containing S-792-Ni is closely related to the formation of filamentous clusters, the decrease of dark zone thickness and the increase of gas phase temperature gradient. In addition, the formation of flocculent network carbon skeleton and the decrease of metal aggregations in the quenched sample also contribute to the improvement of combustion performance. Additionally, the interaction mechanisms of efficient catalyst S-792-Ni with energetic components HMX and NC/NG were revealed by the in-situ solid FTIR and gas-phase MS-FTIR methods. The results show that S-792-Ni can obviously promotes the fracture of C–C bonds and C-N bonds of NC/NG and HMX respectively, and significantly increases the decomposition heat of HMX and NC/NG. The increased decomposition heat are beneficial to the rapid reactions beneath the combustion surface and the heat feedback between combustion surface and gas region, so as to improve the burning rate of HMX-CMDB propellant.