FTIR法研究3,5-二甲硫基-2,4-/2,6-二氨基甲苯二胺扩链剂的扩链动力学  

Investigation on the Cure Kinetics of PUU Elastomers by FTIR

作　　者：李再峰[1] 张彤[1] 牛淑妍[1] 徐春明[2] 

机构地区：[1]青岛科技大学化学与分子工程学院,山东青岛266042 [2]石油大学国家重质油加工实验室,北京100220

出　　处：《光谱学与光谱分析》2003年第6期1107-1110,共4页Spectroscopy and Spectral Analysis

基　　金：山东省教委基金;石油大学国家重点实验室开放基金

摘　　要：采用傅里叶变换红外光谱仪(FTIR)“原位”跟踪了聚氨酯脲的固化过程,实验结果表明:本体聚合反应中,反应初期转化率、反应规律表现为良好的二级动力学关系,给出了反应初期的动力学常数。反应后期高转化率时,反应规律受温度影响较大。温度较低时,反应受扩散控制影响,NCO和NH_2反应的二级反应动力学速率常数逐渐变小;温度较高时,反应速率常数变大。按照反应初期的动力学数据拟合出DMTDA的固化活化能为26.4kJ·mol^(-1),加入催化剂有机锡DBTDL后,反应体系的固化活化能(26.5kJ·mol^(-1))保持恒定,改变DBTDL的浓度,转化率随反应时间变化的动力学曲线保持不变,因此DBTDL对NCO与NH_2的反应无催化作用。否定了脲键自催化的理论,提出了可能的反应机理。The kinetics of curing reaction of polyurethane-urea elastomers was studied by in-situ quantitative FTIR. The reactions, uncatalyzed and catalyzed by dibutyl tin dilaurate(DBTDL), followed 2nd-order kinetics at low conversion. At high conversion, the 2nd-order rate constants for low temperature decreased with an increase in reaction extent, due to the influence of diffusion control, however, it increased with an increase in reaction extent at high temperature. According to the data of kinetics curves at tow conversion, the E-a of the bulk polymerization was 26.4 kJ(.)mol(-1). After addition of catalyst DBTDL, the E-a of the reaction almost remained the same(26.5 kJ(.)mol(-1)). The kinetics plots of conversions vs. time with different concentrations of catalyst DBTDL also remained the same, so DBTDL had no catalytic effect on the reaction of NCO with NH2. The mechanism of urea link self-catalyzed was denied and the possible reaction mechanism was further offered.

关 键 词：3 5-二甲硫基-2 4二氨基甲苯二胺 3 5-二甲硫基-2 6-二氨基甲苯二胺 扩链剂 DMTDA 动力学 聚氨酯脲 固化过程 傅里叶变换红外光谱仪 

分 类 号：TQ314.2[化学工程—高聚物工业]