Curing kinetics of HTPB/TDI/Al system by non-isothermal DSC

Curing processes of HTPB/TDI and Al/HTPB/TDI composites were measured by non-isothermal differential heating calorimetry at different scanning rates. Results show that the values of apparent activation energy, reaction order and frequency factor of HTPB/TDI system are 51.826 kJ · mol^-1, 0.926, 2.412 × 10³ min^-1 respectively. After adding aluminum powder, the peak temperature of the curing process is decreased. The values of apparent activation energy, reaction order and frequency factor are increased to be 76.402 kJ · mol^-1, 0.944, 2.53 × 10⁸ min^-1. respectively. The curing reaction mechanism of HTPB/TDI meets Avrami-Erofeev Equation G(α) =[-ln(1-α)]ⁿ. The addition of aluminum powder into HTPB/TDI curing system only makes little change on index n. The curing reaction of HTPB/TDI can be accelerated by aluminum powder for the initial 18% of reaction extent and aluminum powder slows down the curing reaction for the latter 82% of reaction extent.