The effect of a novel of hyperbranched cross-linking agent on the mechanical of hydroxyl-terminated polybutadiene based solid propellant

Hyperbranched glycidol (HPG) was synthesized from trimethylolpropane (TMP) and glycidol through anionic ring-opening polymerization via one-pot method. Then, toluene di-isocyanate (TDI), 1,4-butanediol (BDO), TMP, and synthetic HPG were used as cross-linking agents to react with Hydroxyl-terminated polybutadiene (HTPB) to prepare polyurethane elastomers (PUs). The structure characteristic of HPG was systematically confirmed by Fourier Transform Infrared Spectroscopy, 1H NMR, and Gel-Permeation Chromatograph. Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), X-ray Diffractograms Analysis, Scanning Electronic Microscopy, and tensile tests were, respectively, carried out to evaluate the properties of various PUs. The results showed that the tensile strength and elongation at break of PUs were greatly improved with the introduction of the cross-linking agent. Compared with pure PUs (none HPG as blank sample), the tensile strength and elongation at break reach 1.23 MPa and 107.24% on the HPG-based PUs, respectively. The TGA and DSC curves indicated that the HPG-based PUs had hardly affected the thermal stability and slightly reduce the glass transition temperature (Tg). The results showed that the introduction of HPG as a cross-linking agent could effectively improved the mechanical properties and lowed temperature resistance of Hydroxyl-terminated polybutadiene (HTPB) based solid propellant.