基于MDI浇注型聚氨酯弹性体密封材料的研制

采用预聚体法以四氢呋喃均聚醚（PTMG）、4,4′-二苯基甲烷二异氰酸酯（MDI）和1,4-丁二醇（BDO）或三羟甲基丙烷（TMP）与BDO混合的扩链剂合成了聚氨酯（PU）弹性体。研究了软段相对分子质量、预聚体NCO基质量分数和扩链剂的用量对聚氨酯弹性体力学性能的影响。实验结果表明：在硬度相同时,PTMG相对分子质量为2000聚氨酯弹性体的撕裂强度、拉断伸长率和冲击弹性高。PU弹性体硬度、撕裂强度和定伸应力随预聚体NCO基相对质量分数增加而增加。用少量三元醇交联的弹性体与完全用二元醇扩链的弹性体相比,定伸应力高,永久变形好。

Development of MDI Based Castable Urethane Elastomer Material

The urethane elastomer was synthesised by prepolymerization method with mixing PTMG, MDI and BDO or TMP and BDO. The effect of soft segmental molecular weight, prepolymer NCO based weight fracture and the amount of chain extender on the mechanical property of PU elastomer was researched. The results showed that, at the same hardness, when the molecular weight was 200, the tear strength, elongation at break and impact resilience of PU elastomer with PTMG molecular weight 2000 were high. The hardness, tear strength and modulus was increased with the molecular weight of prepolymer NCO based increasing. As using PU elastomer crossed with litter triol,the modulus was higher and the set was better than that of diol alone.