KINETICS OF FAST URETHANE POLYMERIZATION IN REACTION INJECTION MOULDING
Gao Yun~* Wang Dening Hu Chunpu Ying Shengkang(Institute of Material Science and Engineering, East China University of Chemical Technology, Shanghai, 200237)
The kinetics of dibutyltin dilaurate(DBTDL) catalyzed fast urethane polymerization of polyoxypropylenepolyoxyethlene triol with uretonimine modified 4, 4'-diphenylmethane diisocyanate (l-MDI) in RIM was studied by infrared spectroscopy and adiabatic temperature rise. For isothermal reaction, the overall reaction order was found to change from 3/2 to 2 with increasing reaction temperature. For adiabatic reaction, the overall reaction order was found to change from 3/2 to 2 with increasing catalyst concentration and hard segment content. The phase separation occured during the RIM urethane polymerization leads to a deviation of the kinetics relationships for higher conversion from those for lower.