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在常压、惰性气体保护下,利用二步法合成甲苯-2,4-二异氰酸酯(TDI)-聚丙二醇(PPG)预聚体,再用少量聚四氢呋喃醚二醇(PTMG)与三羟甲基丙烷(TMP)进行混合扩链交联,制备聚氨酯树脂(PU)固化产物并进行性能研究。采用FTIR对预聚体以及固化产物的分子结构进行表征,用万能试验机测试PU的力学性能。研究结果表明,少量PTMG的加入能降低反应的活性并改善PU固化产物的韧性。当TDI-PPG预聚体中—NCO的质量分数为24.0wt%,扩链交联剂中PTMG的含量为5wt%,异氰酸酯指数(R)介于1.01~1.05之间,PU固化产物具有良好的力学性能,拉伸强度能达到83.0~87.4MPa,弯曲强度达到104~106MPa,拉伸模量达到3.51~3.60GPa,弯曲模量达到3.20~3.28GPa,断裂伸长率达到4.45%~4.83%。
Toluene-2,4-diisocyanate (TDI) -polypropylene glycol (PPG) prepolymer was synthesized by a two-step method under atmospheric pressure and inert gas protection. A small amount of polytetrahydrofuran ether glycol (PTMG) (TMP) were mixed and extended chain cross-linked to prepare polyurethane resin (PU) cured products and performance studies. FTIR was used to characterize the molecular structure of the prepolymer and the cured product. The mechanical properties of the PU were tested with a universal testing machine. The results show that the addition of a small amount of PTMG can reduce the reaction activity and improve the toughness of the PU cured product. When the mass fraction of -NCO in TDI-PPG prepolymer is 24.0wt%, the content of PTMG in the chain-extending cross-linking agent is 5wt% and the isocyanate index (R) is between 1.01 ~ 1.05, the PU cured product has good The tensile strength can reach 83.0 ~ 87.4MPa, the flexural strength reach 104 ~ 106MPa, the tensile modulus reach 3.51 ~ 3.60GPa, the flexural modulus reach 3.20 ~ 3.28GPa and the elongation at break reach 4.45% ~ 4.83%.