聚氨酯弹性体软段对其力学性能的影响

Influence of polyurethane elastomer soft segment on its mechanical performance

先用4, 4'–二苯基甲烷二异氰酸酯(MDI)与不同相对分子质量不同种类低聚物多元醇合成预聚体,再以1, 4–丁二醇(BDO)为扩链剂制备聚氨酯弹性体,考察了软段对聚氨酯弹性体力学性能的影响。结果表明:当预聚体NCO含量相同时,聚酯型聚氨酯弹性体的力学性能整体优于聚醚型的,随低聚物多元醇相对分子质量的增加,聚氨酯弹性体的硬度、300%定伸应力、拉伸强度和撕裂强度降低,拉断伸长率增加,扩链系数为1.00时聚氨酯弹性体的力学性能最好;随预聚体NCO含量增加,聚氨酯弹性体的硬度、300%定伸应力、拉伸强度和撕裂强度提高,拉断伸长率下降。

Firstly the prepolymer was synthesized by using 4,4’-diphenylmethane diisocyanate(MDI)and the oligomer polyols with different relative molecular mass and different types,and then the polyurethane elastomer was prepared by using 1,4-butanediol(BDO)as chain extender.The influence of the soft segment on the mechanical performance of the polyurethane elastomer was investigated.The results show that when the NCO content of the prepolymer is the same,the mechanical performance of the polyester-based polyurethane elastomer is overall superior to that of the polyether-based polyurethane elastomer.With increasing of the relative molecular mass of the oliogmer polyol,the hardness,300%modulus,tensile strength and tear strength decrease,but the elongation at break increases,when the chain extending coefficient is 1.00,the mechanical performance of the polyurethane elastomer is the best.With increasing of the NCO content of the prepolymer,the hardness,300%modulus,tensilie strength and tear strength of the polyurethane elastomer increase,but the elongation at break decreases.