Burning Rate And Ignition Delay Times Of Ap/Htpb-Based Solid Rocket Propellants Containing Graphene

The purpose of additives in solid rocket propellants is to tailor the propellants’ properties, primarily the burning rate and strength. While the use of graphene and its analogs in liquid monopropellants and other fields has been widely studied, there are very few investigations as to its effects on solid rocket propellants. The purpose of this study therefore was to determine the effects of graphene, specifically edge-functionalized graphene oxide (EFGO), on the burning rate, ignition delay time, and tensile strength of AP/HTPB-based solid rocket propellants. Two types of propellants were created, an 80% monomodal and an 85% bimodal, with 1% EFGO by mass in each. The 85% bimodal propellants consisted of one batch with plasticizer and one without. The EFGO was mixed into the propellants in a dry powder form. The samples were tested between pressures of 3.4 and 15.5 MPa (500 and 2250 psi) in a constant-volume vessel pressurized with inert argon gas. Results showed a no significant change in burning rate for the 80% monomodal propellants and only 3.9 and 6.4% increases for the 85% bimodal propellants with and without plasticizer, respectively. A significant increase in ductility and corresponding decrease in elastic modulus were observed for the 85% bimodal propellants. The effects of the graphene on the tensile strength however varied for each propellant type. Results showed that the strength of the 80% monomodal propellants increased, whereas the strength of the 85% bimodal propellants decreased slightly with EFGO addition. With the addition of 1% EFGO, the results showed 30.5 and 81.4% increases in ignition delay times for the 80% monomodal and 85% bimodal propellants with plasticizer, respectively. The ignition delay times of the 85% bimodal propellants without plasticizer increased by 120% compared to the baseline with plasticizer