增塑剂对聚氨酯密封胶性能的影响

The Effect of Plasticizers on the Performance of Polyurethane Sealant

以自制的聚氨酯预聚体为主体原料,配以填料、助剂等配制成单组分湿固化聚氨酯密封胶。讨论了增塑剂对聚氨酯密封胶老化性能的影响,结果显示:当增塑剂与聚氨酯体系的极性相近时,体系的耐迁移性随着增塑剂相对分子质量的增加而增加;当增塑剂与聚氨酯预聚体的相对分子质量相近时,增塑剂的极性与聚氨酯体系越接近,耐老化性能就越优越。通过老化实验表明:增塑剂的相对分子质量对于密封胶的耐紫外性能有一定的抑制作用,湿热是密封胶老化和增塑剂流失的关键原因之一。

One-component moisture curing polyurethane sealant is prepared with polyurethane prepolymer,fillers and additives.The effect of different plasticizers on the aging performance of the polyurethane sealant is discussed,the results show that： when the polarities of plasticizer and polyurethane are similar to each other,the resistance to migration of the system is enhanced with the increase of plasticizer molecular weight;when the molecular weights of plasticizer and polyurethane prepolymer are similar to each other,the closer of their polarities are,the better of the anti-aging properties will be.The aging experiments show that the molecular weight of plasticizer has an inhibitory action on the ultraviolet resistance of sealant,humid and hot condition is one of the key reasons for sealant aging and plasticizer loss.