Nitrate Plasticized Polyether Propellant With Low Burning Rate-Pressure Exponent Based on Branched Poly-(Ethylene Oxide)-Tetrahydrofuran and Dimeryl Diisocyanate

Because nitrate plasticized polyether (NEPE) propellant contains a lot of nitrate plasticizer and nitramine explosives, it generally has a high burning rate and burning rate-pressure exponent. It is found that dimeryl diisocyanate (DDI) can be used as a special “burning rate modifier” in hydroxyl-terminated polybutadiene propellant, while ensuring the energy properties and mechanical properties of the propellant. DDI is introduced into NEPE propellant to regulate the combustion properties, and branched poly-(ethylene oxide)-tetrahydrofuran (B-PET) copolymer is used as binder. The elongation at break, elastic modulus, and tensile strength of (B-PET)-DDI elastomer and propellant are higher than those of PET-N100 elastomer and propellant, which is related to the high cross-linking density and high hydrogen bond content of the (B-PET)-DDI system. Taking NEPE propellant with 42% cyclotrimethylene trinitramine (RDX) as an example, with the increase of pressure, the burning rate of (B-PET)-DDI propellant is gradually lower than that of PET-N100 propellant. After the burning rate-pressure exponent inflection point, the burning rate-pressure exponent of (B-PET)-DDI propellant is obviously lower than that of PET-N100 propellant, which may be closely related to the RDX decomposition in propellant. Compared with the commonly used PET-N100 system, the (B-PET)-DDI system can reduce the burning rate and burning rate-pressure exponent of NEPE propellant with different RDX contents and also has better mechanical properties.