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探讨了聚硫醇/伯胺混合固化剂发生黄变和结皮现象的原因,并对结皮过程的反应机制进行了研究。结果表明:硫醇本身不会发生黄变,黄变现象主要是由于活泼的伯胺基易在O2存在下氧化分解为偶氨基和氧化偶氨基所致;结皮部分有明显的酰胺基伸缩振动特征吸收峰;惰性气体可有效避免黄变和结皮现象的产生。
The reasons for the yellowing and skinning phenomenon of the polythiol / primary amine mixed curing agent were discussed, and the reaction mechanism of the skinning process was also studied. The results show that the yellowing of thiol itself does not occur. The phenomenon of yellowing is mainly attributed to the fact that the active primary amines are easily oxidized and decomposed to the mono- and oxo-amino groups in the presence of O2. Characteristic absorption peak; inert gas can effectively prevent yellowing and crusting phenomenon.