聚氨酯预聚物合成反应动力学研究(Ⅰ)

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

提出一种新的测试聚氨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′一二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 ,分别获得该体系氨酯化反应和支化反应速率常数的Arrhenius表达式 :k1=2 7 1 7exp( -1 9 79/RT) ,k2 =5 886exp( -2 2 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 2 1 66exp( -3 70 0 /T)γ/( 1 -γ ) .

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: 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:Q=0 216 6 exp (-370 0/T)γ/(1 - γ).These results can be verified with 13 C NMR.