新型聚脲潜伏性固化剂的表观反应动力学

Apparent kinetics of latent curing agent for new polyurea

以自制潜伏性固化剂2-异丙基-3-苯基-1,3-恶唑烷(OX)与六亚甲基二异氰酸酯三聚体按照异氰酸酯指数为1.05混合固化,采用动态差示扫描量热法对其固化动力学进行了研究。结果表明:由Kissnger方程计算的表观反应活化能为95.763×10~3 J/mol,结合Crane经验方程计算的反应级数为1.08,以此推断反应的固化机理。其中,OX水解反应为控制步骤,且水解反应速率主要与OX浓度和温度相关。由特征温度与升温速率关系曲线的外推结果可知,该聚脲体系的固化温度应控制在84.9～157.4℃,最佳固化温度为136.8℃。

A self-made latent curing agent,2-isopropyl-3-phenyl-1,3-oxazole(OX)was mixed with hexamethylene diisocyanate tripolymer and cured according to the isocyanate index of 1.05,whose curing kinetics was studied by differential scanning calorimeter.The results show that the apparent activation energy calculated by Kissinger equation is 95.763×10^3 J/mol,and the reaction order is 1.08 by Crane empiric equation.The curing mechanism of this reaction is inferred that the hydrolysis reaction of OX is a control step,and the reaction rate is decided by the concentration of OX and the temperature.The extrapolation results obtained from the curves of characteristic temperature as a funciton of heating rate indicate that the curing temperature of the system should be controlled between 84 and 157℃,and the optimal curing temperature is 136℃.