Effect of Microstructure of Hydroxyl Terminated Polybutadiene (HTPB) on the Pot-Life of HTPB-Based Binder System: A Brief Review

The binder slurry based on hydroxyl terminated polybutadiene (HTPB) should have a good viscosity at the end of the mixing for easy casting. The time available for proper casting of the bonding system after the addition of the curing agent is called pot life. A brief review on the effect of HTPB microstructural parameters on the pot life of high feld HTPB-based composites is very important. HTPB microstructural parameters include average molecular weight (numerical and weight) and its distribution, hydroxyl content (value), high molecular weight fraction, functional group distribution and its type distribution, and relative concentration of microstructures (cis, trans, vinyl). In this paper, by introducing each of the HTPB microstructural parameters, the effect of each one on the pot life of high feld composite binder system is investigated and the possibility of controlling the life of this system by rearrangemet of the prepolymer microstructure without any decrease of mechanical properties is discussed. A review of the results showed that increasing the average molecular weight and the amount of hydroxyl of HTPB decreased the pot life and species with low functional group increased the pot life of the system.