聚酯软段对聚氨酯弹性体力学性能影响的研究

Effect of Soft-segment of Polyester on Mechanical Properties of Polyurethane Elastomer

以不同结构聚酯多元醇(PEA、PEPA、PBA、PCL)为软段,4,4′-二苯基甲烷二异氰酸酯(MDI)和1,4-丁二醇(BDO)为硬段采用预聚法合成了聚氨酯(PU)弹性体。讨论了MDI/BDO体系中软段种类、相对分子质量、预聚体NCO含量及催化剂对PU弹性体力学性能的影响,并与TDI/MOCA体系进行比较。结果表明,当软段相对分子质量相同时,以PBA为原料合成的PU弹性体硬度最高,弹性体的拉伸强度、伸长率和冲击弹性均随软段相对分子质量的增加而增加;提高预聚体NCO含量可使PU弹性体的硬度、撕裂强度和300%模量增加;但加入催化剂的PU弹性体,其拉伸强度下降16.6%～20.1%;MDI/BDO体系PU弹性体的撕裂强度和冲击弹性较高,TDI/MOCA体系PU弹性体的拉伸强度较好、永久变形较低。

With the prepolymer method,a series of polyurethane（PU） elastomer were synthesized using poly- ester （ PBA, PEA, PEPA, PCL） as soft segment, 4,4′-diphenylmethane-diisoyanate （ MDI ） , and 1,4-butanediol （BDO） as hard segment. The influence of type and molecular weight of soft segment, NCO content in perpolymer and catalyst on the mechanical properties of the PU were discussed. The system of MDI/ BDO was in comparison with TDI/MOCA. The results showed that when molecular weight of soft segment of polyester were similar, the hard- ness of PBA-PU elastomer was the highest. The tension strength, elongation and impact elasticity of elastomer were increased with the molecular weight of the soft segment increase. The hardness, tear strength and modulus of PU were increased with the increase of the content of NCO in prepolymer. The tension strength of elastomer descend 16.6% - 20.1% with the catalyst adding. In the system of MDI/BDO/PU the tear strength and resilience were bet- ter,but in the system of TDI/MOCA/PU the tensile strength was higher,and permanent deformation was lower.