【摘要】 首先以聚己内酯多元醇(PCL)、4,4′-二苯基甲烷二异氰酸酯(MDI)、液化MDI和MDI-50为原料合成聚氨酯(PU)预聚体,再用混合扩链剂制备聚氨酯弹性体。讨论了预聚体异氰酸酯基(NCO)含量、异氰酸酯类型、1,3-丁二醇(1,3-BDO)含量、聚酯软段相对分子质量对聚氨酯弹性体力学性能的影响。结果表明:提高预聚体NCO基含量可使弹性体的硬度、300%定伸应力、拉伸强度和撕裂强度明显提高,拉断伸长率和冲击弹性则下降;纯MDI弹性体综合力学性能最好,液化MDI次之,MDI-50最差;提高1,3-BDO含量可使弹性体的硬度、撕裂强度和冲击弹性明显下降;软段相对分子质量为1 000的聚氨酯弹性体的硬度、300%定伸应力、拉伸强度和撕裂强度较高,软段相对分子质量为2 000的聚氨酯弹性体的拉断伸长率和冲击弹性较高。更多还原

【Abstract】 Polyurethane prepolymer was synthesized by using 4,4′-diphenylmethane diisoyanate(MDI),liquidated-MDI,MDI-50 and poly-ε-caprolactone glycol(PCL) as raw materials.Polyurethane elastomers were prepared by using blend chain extenders.The influences of mass fraction of —NCO in prepolymer,types of isocyanate,the mass fraction of 1,3-butanediol and molecular weight of soft segment on the mechanical properties of polyurethane elastomer were investigated.The results showed that the hardness,300% modulus and tear strength were enhanced rapidly when percentage of NCO in prepolymer was increased,but elongation and impact elasticity decreased.The MDI / PU had the best mechanical property,liquidated-MDI/PU lower,MDI-50/PU was lowest.The hardness,tear strength and impact elasticity decreased rapidly when the mass fraction of 1,3-butanediol was increased.The PU made from Mn=1 000 soft segment had higher hardness,300% modulus,tensile strength and tear strength;the PU had higher elongation and impact elasticity when molecular weight of soft segment was Mn=2 000.更多还原