Fluorescence monitoring of polymerization reaction.: A new method for treating fluorescence experimental data

A new method has been found for monitoring polymerization reactions in situ and in real time. The first moment of fluorescent emission, <v> = SigmaI(F)(v)v/SigmaI(F)(v) is calculated from fluorescence spectra as a function of polymerization time and can be successfully correlated with the conversion of functional groups, obtained by an independent technique, with a very low level of experimental scatter. The statistical analysis of the method has been performed; some simple computer experiments allowed to study the influence of the most important experimental variables yielding the confidence interval of <v> as a function of the noise to signal ratio. This method was applied with stepwise polyaddition (epoxide curing) and polymerization by free radical mechanisms. 5-Dimethylaminonaphthalene-1-sulfonamide derivatives, 4-dialkylamino-4'-nitrostilbene and pyrene were used as probes and/or labels. Other methods reported in the literature have been applied also. Comparison with them reveals that the first moment method is more reliable for monitoring polyaddition reactions. (C) 2002 Elsevier Science Ltd. All rights reserved.