Lowering the burning rate temperature coefficient of composite propellant by compensating its burning surface through thermal expansion and contraction in microstructure

How to reduce or eliminate the influence of initial ambient temperature on the interior ballistic of solid propellant (SP) has always been a technical bottleneck, and little progress has been made in recent years. The research of solid propellants with low burning rate temperature coefficient (delta p) mainly focuses on the use of temperature insensitive oxidants, but rarely from microstructure. In this work, cellulose acetate (CA), dioctyl adipate (DOA) and paraffin wax (PW) with high coefficient of linear thermal expansion were coupled with solid propellant energetic mesoparticle (SPP)-ammonium perchlorate (AP)/Al/CoWO4-reduced graphene oxide (rGO)/nitrocellulose(NC) through electrospray granulation method to form thermal expansion and contraction solid propellant mesoparticles (ECSPPs): CA-SPP, DOA-SPP and PW-SPP, followed by being used in solid propellants (SPs): SP-Co, SP-CA, SP-DOA and SP-PW. It suggests that recrystallized nano-AP is tightly packaged with efficient catalyst CoWO4-rGO, significantly improving the decomposition efficiency of AP and reaction efficiency of Al-AP to reduce the temperature-sensitivity of AP. For ECSPPs, PW significantly reduces the temperature sensitivity of AP which decrease the delta p of PW-SPP by 68.5 % at -40 - 0 degrees C. Compared with SP-Co, the delta p of SPDOA and SP-PW at 3 MPa and -30 - 0 degrees C are reduced by 20.7 % and 77.1 %, and the delta p of SP-CA, SP-DOA, SPPW at 5 MPa and -30 - 0 degrees C are reduced by 36.9 %, 35.3 %, 80.9 %. Thus, PW exhibits the optimal reduction effect on temperature sensitivity of AP, as a consequence of ECSPPs compensating for the burning surface through morphological changes in the microstructure with initial temperature. This study provides a novel strategy for reducing the delta p structurally through compensation for the burning surface.