A polyurethane binder with excellent mechanical properties based on copolymerization and dynamic bond crosslinking

Abstract

Hydroxyl-terminated polybutadiene (HTPB) based polymer binder is expected to possess exceptional mechanical performances, as the matrix of composite solid propellant. In this study, HTPB and hydroxyl-terminated polyether (HTPE) were copolymerized by isocyanate (IPDI) to form HTPB-HTPE, and then ZnCl2 was added to prepare a polyurethane binder (HTPB-HTPE-Zn) with excellent mechanical performances. The thermal properties and dynamic mechanical characteristics of the synthesized polyurethane were characterized by a differential scanning calorimeter, dynamic thermomechanical analyser, and Instron universal testing machine. The experimental results show that HTPB-HTPE-Zn exhibits significantly enhanced elongation at break (1122.52%) and basically unchanged tensile strength (0.37 MPa), compared with pure HTPB (503.42%/0.38 MPa). This work provides a method for preparing binders with high mechanical properties and broadens the application field of HTPB-based polyurethane.