Isophorone Diisocyanate and Trimethylolpropane in-situ Prepared Hydroxyl-Terminated Block Copolymer Binder with Excellent Mechanical Properties

A novel hydroxyl-terminated block copolymer (ITPP) binder was prepared through an in-situ preparation method. The new binder having similar block structure as HTPE binder, without complex synthesis process to prepare HTPE prepolymer intermediate, reduces cost and optimizes the preparation process. Thus, it is expected to be used as binder of insensitive propellant. Infrared spectroscopy, low-field nuclear magnetic resonance, and uniaxial tensile testing were used to investigate the curing networks and mechanical properties of the binder. The crosslink density V_e increased with the increase of TMP content and R value. The ultimate tensile strength σ_m of the in-situ-prepared ITPP binder is 20.50 MPa and the percentage of breaking elongation ε_b is 743.47%. Additionally, in order to study the pot life of the in-situ-prepared ITPP binder, the rheological properties of the curing reactions were also studied. Finally, compared to HTPE binder, the in-situ-prepared ITPP binder’s strength and elongation increase by 694 and 276%, respectively. Besides, the in-situ-prepared ITPP binder has better process performance. This exciting result greatly enhances that the in-situ-prepared ITPP binder has great potential for application in rocket propellant formulations.