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

ABSTRACT 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.