【摘要】 依据反应动力学和能量守恒方程的基本理论 ,对聚氨酯反应注射成型的固化过程进行了合理的假设和必要的简化 ,建立了体系反应程度和温度的数学模型。采用显示有限差分法并结合数学软件Matlab对固化过程进行了动态模拟。结果表明 :固化初始的 2 0s内交联反应剧烈 ,体系迅速升至最高温度 ,交联度达到 80 %所需时间与经验值一致 ,约为 17s。同时为优化反应注射成型工艺因素 ,探讨了催化剂浓度、原料初始温度和模具温度等对体系的影响。结果表明 :催化剂浓度增加 ,使体系固化周期缩短 ,制品内部交联度的变化减小 ,但延长了制品处于高温部分的时间 ;模具温度主要影响制品壁面附近的反应 ,而物料初始温度则能影响到体系的最高温度 ,尤其是在低模温情况下更加明显更多还原

【Abstract】 An attempt was made to develop a mathematical model for the curing behavior of polyurethane during the reaction injection molding. Reasonable assumptions and simplifications were introduced in the model, and an explicit finite difference scheme with the mathematical software Matlab was used to obtain temperature and conversion distribution in the thickness direction for a plate-type mold. The temperature and conversion calculated from the simulation was consistent compared with the experimental data. The demolding time, i.e., the time needed to achieve a minimum conversion of 80%, was found about 17s. In addition, the effects of catalyst concentration, feed temperature and wall temperature on the maximum exothermic temperature and the conversion were also explored to optimize molding conditions of reaction injection molding of polyurethane.更多还原