Study on the Influence of Polyethylene Oxide on the Structure and Low-Temperature Mechanical Properties of Branched Glycidyl Azide Polymer Solid Propellant

To improve the low-temperature mechanical properties of branched glycidyl azide polymer (BGAP) propellants, a flexible chain polymer, polyethylene oxide (PAO), was introduced into the BGAP binder system, and a series of BGAP/PAO elastomers with different blending ratios were prepared. The study focused on investigating the microscopic interaction of PAO with the binder cross-linking network, as well as its macroscopic impact on the properties of the elastomers. The results indicated that the crystallization behavior of PAO can introduce physical cross-linking points in the binder system, leading to an approximately eight-fold increase in tensile strength at both room and low temperatures. Furthermore, PAO enhances the mobility of chain segments, which, in turn, reduces the glass transition temperature of the binder system and improves elongation at low temperatures. Building upon these findings, the study further investigated the influence of PAO on the interaction between the BGAP binder system and solid fillers. A comparison was made between the structural and performance variations of BGAP/PAO elastomers and BGAP/PAO-based solid propellants. Ultimately, the optimal formulation of the BGAP/PAO binder system for solid propellants was determined. The results revealed that PAO crystallization reduces the interaction between the binder system and propellant fillers, leading to severe dewetting. This emphasizes the need to precisely control the amount of PAO added to fine-tune the low-temperature performance of the propellant.