Intrinsic Fluorescence Cure Sensor for Reaction Monitoring in Polyurethane

摘要

Fluorescence spectroscopy and UV absorption were used as main tools to monitorthe reaction of methylene diphenyl-4-4'-diisocyanate (MDI) with 1-butanol, poly(propylene oxide) (PPO) and diethyl toluene diamine, (DETDA) using the curing agent MDI as a chemical and spectroscopic sensor. The MDI virtually has no fluorescence, but shows strong fluorescence emission at about 310 nm after changing into urethane. The emission of DETDA appears at 343 nm which is about the same wavelength as that of the urea formed. However, the urea shows higher fluorescence quantum yield. The fluorescence intensity changes were applied to monitor the polymerization process. FTIR was used to obtain the extent of reaction by following the disappearance of the isocyanate group. Correlation curves between the fluorescence intensity changes and IR results were derived making the fluorescence changes applicable in the estimation of the extent of reaction. Intrinsic fluorescence, Methylene Diphenyl Diisocyanate (MDI), Polyurea, polyurethane, Butane diol, Diethyl toluene diamine.