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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。
Homemade polyurethane prepolymer as the main raw material, together with fillers, additives formulated into one-component moisture-curing polyurethane sealant. The effects of plasticizers on the aging properties of polyurethane sealants are discussed. The results show that when the polarities of plasticizer and polyurethane system are similar, the migration resistance of the system increases with the increase of relative molecular mass of plasticizer. When the relative molecular mass of plasticizer and polyurethane prepolymer is similar, the closer the polarity of plasticizer to the polyurethane system, the better the anti-aging property. The aging experiment shows that the relative molecular weight of plasticizer has a certain inhibitory effect on the UV resistance of the sealant. Wet heat is one of the key reasons for sealant aging and plasticizer loss.