Design, Synthesis, and Performance of Photocurable Polyether Binders for Solid Propellants

To develop a binder system suitable for photocurable additive manufacturing of solid propellants, this study utilizes ethylene oxide-tetrahydrofuran copolyether (PET), a commonly employed binder in solid propellants, as foundational material. By modifying terminal groups, two photocurable binders are synthesized: allyl-terminated polyether (AUPET) and acrylate-terminated polyether (PUA). The exothermic behavior of photopolymerization and the mechanical properties of these binders are comprehensively investigated. PUA exhibits a significantly faster photopolymerization rate than AUPET, enabling rapid photocuring and molding. Both binders demonstrate photocuring capability in the presence of thiols. Mechanical property testing indicates PUA forms brittle films under self-curing conditions, with a tensile strength of 1.18 MPa and an elongation at break of 81.07%, whereas AUPET, upon curing in the presence of thiol, exhibits enhanced flexibility, showing a tensile strength of 0.37 MPa and an elongation at break of 587.49%. Additionally, incorporating a triazine ring structure significantly enhances the tensile strength of PUA and AUPET films, the presence of thiols improves their elongation at break.