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通过示差扫描量热分析,固化时间和p H值测定研究了分别添加2种潜伏固化剂(六亚甲基四胺+过硫酸铵+对甲基苯磺酸+二乙醇胺,过硫酸铵+磷酸氢二铵)和常规固化剂氯化铵的脲醛树脂不同温度下的固化行为。结果表明,两种潜伏型固化剂的固化起始温度、峰顶温度均高于氯化铵,低温潜伏性能较好。低于固化起始温度时,添加两种潜伏固化剂的脲醛树脂体系p H值呈现中性偏碱,超过固化起始温度后,随着固化温度提高,脲醛树脂体系的p H值下降速度先慢后快,固化时间缩短。可以通过调控温度、p H值和时间三者关系实现对脲醛树脂预固化行为的控制。
Analysis by Differential Scanning Calorimetry, Cure Time, and p H Value The effects of two latent curing agents (hexamethylene tetramine + ammonium persulfate + p-toluenesulfonic acid + diethanolamine, ammonium persulfate + phosphoric acid Hydrogen diammonium) and the conventional curing agent of urea formaldehyde resin at different temperatures curing behavior. The results show that the curing initiation temperature and peak temperature of two latent curing agents are higher than that of ammonium chloride, and the latent performance at low temperature is better. Below the curing initiation temperature, the p H value of the urea formaldehyde resin system with two latent curing agents showed a neutral partial base. After the curing initiation temperature was increased, the decreasing rate of the p H value of the urea formaldehyde resin system Slow fast, curing time shortened. The pre-curing behavior of urea-formaldehyde resin can be controlled by controlling the temperature, p H value and time.