Abstract:

MDI-50 type polyurethane elastomer was prepared from a prepolymer system based on MDI-50，polyol and MOCA chain extender. The effects of mass fraction of —NCO in prepolymer on properties of the elastomer were studied. The structure and performance were analyzed by means of DSC，TG，FTIR and mechanical properties test. The results showed that hardness and glass transition temperature of MDI-50 type polyurethane elastomer increased with increasing molar ratio of NCO/OH in prepolymer reactive system. The tearing strength and tensile intensity increased at first and then declined with increasing mass content of —NCO. However，elongation at break of the elastomer and viscosity of prepolymer decreased with increasing —NCO mass content. It showed that better properties were obtained at 2.22 of the molar ratios of NCO/OH. —NCO mass content had little influence on thermal stability of the elastomer .The result provided data for the application of formula design of MDI-50 type polyurethane elastomer.

摘要：

以聚醚多元醇和MDI-50为原料，采用预聚物法合成预聚体，再和扩链剂MOCA进行扩链合成聚氨酯弹性体。研究了预聚体中不同异氰酸酯基（—NCO）质量分数对MDI-50型聚氨酯弹性体性能的影响。采用差示扫描量热分析（DSC）、热重分析（TG）、红外光谱（FTIR）及力学性能等测试方法对聚氨酯弹性体的结构与性能进行了表征和分析。结果表明：预聚体反应体系中NCO/OH摩尔比增大，预聚体中—NCO质量分数增加，预聚体的黏度降低，相应的聚氨酯弹性体的硬度和玻璃化转变温度提高，断裂伸长率降低，而拉伸强度和撕裂强度先增加后下降；当NCO/OH摩尔比为2.22时，聚氨酯弹性体力学性能较好；—NCO质量分数对聚氨酯弹性体的热稳定性影响不大。