An investigation of the effects of pre-polymer functionality on the curing behavior and mechanical properties of HTPB-based polyurethane

In this study, the effective functionalities obtained from gel point, dynamic mechanical thermal analysis (DMTA) and tensile tests were compared. Three types of hydroxyl-terminated polybutadiene (HTPB) resins with different functionalities were cured with different curing agents. Results revealed that the functionalities obtained from gel point test were not the same as those obtained from tensile test. Also, the HTPB with the lowest effective functionality resulted in the elastomer with the lowest cross-linking density and stress at break. However, the HTPB with the highest effective functionality did not cause the greatest cross-linking density and stress at break.