Pyrene Fluorescence as a Probe for the Monitoring of Polymerization Processes: Simultaneous DSC and Fluorescence Study

Abstract

The polymerization of cyclohexylmethacrylate was monitored, over a wide temperature range, by simultaneous differential scanning calorimetry (DSC) and fluorimetry (FL); the equipment for both being optically coupled. Pyrene was used as a fluorescent probe. There was excellent agreement between the exothermic peak time obtained by DSC and the time at which the maximum gradient was obtained in the fluorescence intensity–time curves, but only for temperatures above 60°C, Activation energies for the gel effect onset were obtained for both, the conversion–time and intensity–time curves being concordant except for data at low temperatures, below 60°C. It was concluded that vitrification occurs at temperatures below 60°C and its presence was demonstrated by fluorimetry, by means of the conversion change associated with the fluorescence intensity jumpΔα_(off-on).