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Thermal and mechanical properties of two kinds of hydroxyl-terminated polyether prepolymers and the corresponding polyurethane elastomers

In order to analyze the differences in performance between two kinds of hydroxyl-terminated polyether (HTPE) binders, the curing reaction kinetics of the prepolymers and polyfunctional isocyanate (N-100) molecules and the thermal properties of the prepolymers and the corresponding polyurethane (PU) elastomers were studied by non-isothermal differential scanning calorimetry. The mechanical properties of PU elastomers were also studied by uniaxial tensile tests. With these data, the binder type could be chosen more appropriately for its application in rocket propellant formulations. The results showed that the reactivity of hydroxyl-terminated block copolyether (TPEG) with an isocyanate group is higher than that of hydroxyl-terminated random copolyether (PET). The chain flexibility of TPEG was less than that of PET, but the stereoregularity and crystallization ability of the former were superior. Compared to the prepolymers, the chain flexibility of the corresponding PU elastomers was reduced, and the crystallization ability became weaker such that their onset of crystallization was delayed. After the prepolymers were reacted with N-100, the thermal properties of PU elastomers remained consistent with their respective prepolymers. In summary, it was concluded that the mechanical properties of TPEG/N-100 PU elastomer films were found to be superior to the PET/N-100 films.