Abstract:
PBT polyether polyurethanes with different active hydrogen components were prepared by a two-step method using 3, 3-diazymoxy-tetrahydrofuran copolymer (PBT) as the soft segment of polyether polyurethanes, toluene diisocyanate (TDI) as the curing agent, diethylene glycol (DEG) as the chain extender and trimethylol propane (TMP) as the crosslinking agent. The curing reaction kinetics and mechanical properties of PBT/TDI, PBT/TDI/DEG, PBT/TDI/TMP and PBT/TDI/DEG/TMP systems were studied by Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimeter (DSC), electronic universal testing machine and swelling ratio test. The results show that the curing reactions of PBT/TDI, PBT/TDI/DEG, PBT/TDI/TMP/ and PBT/TDI/DEG/TMP systems are second-order reactions, and the activation energies of these systems are 135.984, 165.573, 164.933 and 164.292 kJ/mol, respectively. The addition of DEG can significantly increase breaking elongation of the adhesive matrix, but the tensile strength decreases; The addition of TMP can improve the tensile strength of the adhesive matrix and reduce breaking elongation; when DEG and TMP exist simultaneously, the tensile strength of the adhesive matrix increases and the elongation at break decreases. DEG and TMP can both improve the crosslinking density of the curing systems.