Investigation of the Effect of Binary and Tertiary Curing Agents on Pot Life of Binder System Based on HTPB

The aim of this research was to investigate the effect of binary and tertiary curing agents on pot life of binder system based on HTPB using less reactive ones such as IPDI and HDI in combination with TDI. Polymerization rate in the presence of each of TDI, IPDI and HDI was individually studied using rheological method at 60 °C, where a two-step kinetic behavior (for TDI and IPDI) was observed. Measuring the pot life of binders using binary curing agent systems such as TDI:IPDI and TDI:HDI with 1:3 ratio, showed pot lives of 285 min (about 12% increase in comparison to single TDI system) and 195 min (about 24% decrease in comparison to single TDI system), respectively. The important point was abnormal decrease in pot life for binder system usnig TDI-IPDI binary curing agent, which can be related to catalytic role to HDI. In continuous, HDI was added to TDI-IPDI binary curing system (with pot life of 285 min). The pot life of TDI-IPDI-HDI tertiary curing system reached to 270 min (15 min decrease), which can emphasize again the catalytic role of HDI in the polymerization reaction.