聚氨酯快速(RIM)聚合的绝热反应动力学

用环氧乙烷封端的聚环氧丙烷聚醚二元醇与4,4’-二苯基甲烷二异氰酸酯(MDI)或液化改性的MDI(L-MDI)进行快速本体聚合,比较了二月桂酸二丁基锡(DBTDL)、辛酸亚锡(SnOct)、硫醇锡(UL-29)以及相应的几种锡/胺体系在绝热条件下的催化活性.用非线性优化方法求取了反应动力学参数值.结果表明,在绝热条件下本体聚合的反应活化能为130～170kJ/mol,每当量NCO官能团的反应热为61～72kJ.催化剂的活性顺序为:SnOct>DBTDL>UL-29和BDTDL/DABCO(三乙烯二胺)>UL-29/DABCO>Snoct/DABCO.反应总级数为2级,催化剂种类的变化对反应总级数基本上无影响.

ADIABATIC REACTION KINETICS DURING FAST (RIM) POLYMERIZATION OF POLYURETHANE

The fast (Reaction injection molding, RIM) polymerization was carried out by reacting ethylene oxide capped poly (propyl oxide) polyether diol (PPO) with 4,4'-diphenyl-methylene diisocynate (MDI) or liquefied MDI (L-MDI). Catalyst activity was compared for dibutyltin dilaurate (DBTDL), starmous octoate (SnOct), alkyl tin mercaptide (UL-29) and corresponding organotin/triethylene diamine (DABCO) systems in the polymerization process. Kinetic parameters were calculated with a non -linear optimization technique for a simple nth order model with an Arrhenius temperature dependence. The results suggest that activation energy is 130-170 kJ/mol and reaction heat is 61-72 kJ/eq. NCO. The catalyst activity is ordered as SnOct>DBTDL>UL - 29 and DBTDL/DABCO>UL - 29/DAB-CO>SnOct/DABCO. Overall reaction order is about 2 that is not related to catalyst activity.