Preparation and characterization of polymers with branched architecture

Abstract

Polymer binders make up the structural matrix of solid propellants. They play a role in determining the properties of the propellant. Currently, there are not many studies done on hyperbranched polyurethane (HBPU) for use as a polymer binder. In this project, HBPU synthesized through cationic ring-opening polymerization of 3-azidomethyl-3-hydroxylmethyl oxetane and cured with isocyanate was studied. This project aims to synthesize and characterize the mechanical properties of HBPU. The glass transition temperature, and thermal and viscoelastic properties of the material, were investigated. The results indicate that HB-TMP-GAP has a larger OB% as compared to that of BDO-GAP and shows a larger percentage of weight loss in TGA. This suggests that HB-TMP-GAP has better combustion capabilities than BDO-GAP. The addition of DBP plasticizer results in a decrease in elasticity of the HBPU. A decrease in the NCO/OH ratio and an increase in the weight percentage of plasticizer results in a decrease in the glass transition temperature of the HBPU. However, the Tg of the HBPU obtained from this project is too high for the application as a binder material.