THE STUDY ON THE CHAIN EXTENSION REACTION OF MDI AND TDI TERMINATED POLYESTER PREPOLYMERS WITH EXTENDERS

The effects of the hard segment structure on the chain extension react ion kinetics of MDI or TDI terminated PEPA-prepolymer with diamine(MOC A) and polyol(TMP) have been studied by FTIR method systematically, Th e reaction fate constants and activation energy for these systems have been measured. The chain extension reactions in these systems are fou nd to be reactions of second order, The chain extension reaction of NC O terminated PEPA-MDI-prepolymer with MOCA or TMP is faster than that of PEPA-TDI-prepolymer with the same extenders, The activation energy of the chain extension reaction of NCO terminated PEPA-prepolymer with MOCA is much lower than that with TMP, Such chain extension reaction difference has been discussed.