紫外老化对聚醚-MDI型聚氨酯弹性体性能的影响

Effect of Ultrav iolet Aging on Properties of Polyether-MDI Polyurethane Elastomer

采用紫外老化加速方法模拟高分子材料自然老化现象,探究聚氨酯材料老化前后性能差异,为聚氨酯制品工业化生产参数的选定提供参考。选择聚醚-二苯基甲烷二异氰酸酯(MDI)预聚物为研究对象,一步法合成了聚醚-MDI型聚氨酯弹性体试样,对试样的力学等性能进行了测试,同时对紫外加速老化120 h,240 h后的试样也做了同种性能测试。结果发现,紫外老化前后试样的拉伸强度由21.8 MPa提高至30.8 MPa,撕裂强度由93 kN/m上升到109 kN/m,氧指数由23.4%下降至21.4%,其他方面性能均无明显变化,分析可能是受到端基官能团和物料内部残留的少量扩链剂等因素影响,聚氨酯内部结构及柔顺性出现了微妙改变,导致其相关性能出现了不同程度的变化。

An accelerated ultraviolet aging method was used to simulate the natural aging of polyurethane materials,which was adopted to explore the differences of properties of polyurethane materials before and after aging,so as to provide reference for the selection of industrial production parameters of polyurethane products. Polyether-diphenylmethane diisocyanate (MDI) prepolymer was selected as research object and the samples were synthesized by one-step method. The mechanical and other properties of the samples were tested. At the same time,the samples after ultraviolet accelerated aging for 120 h and 240 h were also tested. According to the results,the tensile strength of samples before and after ultraviolet aging is increased from 21. 8 MPa to 30. 8 MPa,the tear strength is increased from 93 kN/m to 109 kN/m,the oxygen index is decreased from 23. 4to 21. 4,and there is no significant change of other properties of samples. The internal structure and flexibility of polyurethane are influenced slightly by the end-group functional groups and a small amount of chain extenders that may remain in the material,which lead the different degrees of changes for related performance.