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以聚四氢呋喃醚二醇(PTMG)、4,4′-二苯基甲烷二异氰酸酯(MDI)和1,4-丁二醇(BDO)为原料,通过预聚体法制得不同异氰酸酯(—NCO)基含量预聚体,用BDO作扩链剂合成浇注型聚氨酯(PU)弹性体。考察了预聚体中—NCO基含量对PU弹性体力学性能的影响,用X射线衍射仪、维卡软化点测定仪和热失重分析仪对材料进行分析表征。结果表明:PU弹性体随预聚体—NCO基含量的增加,硬度、拉伸强度、模量和撕裂强度增大,断裂伸长率和冲击弹性下降。当预聚体—NCO基含量为8.0%时,PU弹性体的综合力学性能最佳,拉伸强度和撕裂强度分别是39.4MPa和142.7kN/m;维卡软化温度达到127.5℃,具有较好的热性能。
Different isocyanates (-NCO) were prepared by prepolymer method using polytetrahydrofuran ether glycol (PTMG), 4,4’-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BDO) Based prepolymer, BDO as a chain extender synthetic cast polyurethane (PU) elastomer. The influence of the content of -NCO groups in the prepolymer on the mechanical properties of PU elastomer was investigated. The materials were characterized by X-ray diffraction, Vicat softening point and thermal gravimetric analyzer. The results show that with the increase of the content of prepolymer -NCO, the hardness, tensile strength, modulus and tear strength of PU elastomer increase, while the elongation at break and impact elasticity decrease. When the content of prepolymer -NCO is 8.0%, the mechanical properties of PU elastomer are the best, the tensile strength and tear strength are 39.4MPa and 142.7kN / m, Vicat softening temperature is 127.5 ℃, Good thermal performance.