聚氨酯预聚物合成反应动力学研究

Studies on the Reaction Kinetics of NCO/OH in Preparing Polyurethane Prepolymer

本文提出了一种新的测试聚氯酯预聚物合成反应过程中氨酯化反应和支化反应的动力学参数的理论模型。通过化学定量分析4,4′—二苯基甲烷二异氰酸酯(MDI)与聚四甲撑醚二醇(PTMG)反应体系中的—NCO和—OH的浓度,分别获得了该体系的氨酯化反应和支化反应的速率常数的Arrhenius表达式: k_1=27.17 exp(-19.79/RT) k_2=5.886 ecp(-22.86/RT)在此基础上得到了支化概率Q与反应温度T、羟基转化率γ的关系: Q=0.2166 exp(-370.0/Y)γ/(1-γ)该结果与^(13)C NMR所测得的结果相吻合。

A new theoretical model to study the reaction kinetics of NCO and OH in preparing polyurethane prepolymer is proposed. The Arrhenius equations of urethane and branch reactions are obtained respectively as: k_1=27.17 exp (-19.79/R T) k_2=5.886 exp (-22.86/R T). The relationship between branch probability Q and reaction temperature T and OH-group shift ratio γ is derived as: Q=0.2166 exp (-370.0/T)γ/(1-γ) These results can be verified with ^(13)C NMR.