Abstract In this work, melamine-urea-formaldehyde (MUF) resins with different melamine levels added at different stages were synthesized. The acidic buffering capacity and gel time of the MUF resins were measured. The curing behaviour of MUF resins with different acidic buffering capacities was studied by differential scanning calorimetry (DCS). The morphology of the cured MUF resins was obtained by a scanning electron microscope. The results show that the acidic buffering capacity of MUF resin increases with the alkalinity increment of melamine derivatives in the MUF resin. The acidic buffering capacity and condensation reactivity of the MUF resin jointly affect the gel time of the MUF resin. The lower the reactivity of the MUF resin was, the greater the influence of the acidic buffering capacity on gel time. The higher the reactivity of the MUF resin was, the smaller the influence of the acidic buffering capacity on gel time. The addition of melamine to the MUF resin enhanced the degree of cross-linking of cured MF and MUF components in the MUF resin but weakened the degree of cross-linking of the cured UF component under the same curing environment.

中文翻译：

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三聚氰胺-脲-甲醛树脂的酸性缓冲能力及固化工艺

摘要 在这项工作中，合成了在不同阶段添加不同三聚氰胺含量的三聚氰胺-脲-甲醛（MUF）树脂。测量了 MUF 树脂的酸性缓冲能力和凝胶时间。通过差示扫描量热法 (DCS) 研究了具有不同酸性缓冲能力的 MUF 树脂的固化行为。通过扫描电子显微镜获得固化的 MUF 树脂的形态。结果表明，MUF树脂的酸性缓冲能力随着MUF树脂中三聚氰胺衍生物碱度的增加而增加。MUF树脂的酸性缓冲能力和缩合反应性共同影响MUF树脂的凝胶时间。MUF树脂的反应性越低，酸性缓冲能力对凝胶时间的影响越大。MUF树脂的反应活性越高，酸性缓冲能力对凝胶时间的影响越小。在MUF树脂中加入三聚氰胺提高了MUF树脂中固化MF和MUF组分的交联度，但在相同固化环境下减弱了固化UF组分的交联度。