Wavelength--Shift Fluorescent Probes for Monitoring of Polymerization
Francis W. Wang, R E. Lowry
The feasibility of using wavelength-shift fluorescent probes for cure monitoring of an epoxy resin and an acrylic resin was evaluated. 4-(N,N-dihexylaminostyryl)-4 -pyridinium propylsulfonate (DHASP-PS), as well as each of other wavelength-shift fluorescent probes, was dissolved in the epoxy resin, a stoichiometric mixture of diglycidyl ether of bisphenol A and 4,4 -methylene-bis-(cyclohexylamine). The fluorescence and the excitation spectra of each of the probes dissolved in the epoxy resin were then measured at various times during the cure of the epoxy resin at 60 C. The fluorescence and the excitation spectra of the probe DHASP-PS dissolved in methyl methacrylate were also measured at various times during the cure of the acrylic resin at 55 C.Since the peak fluorescence wavelength of each of the wavelength-shift fluorescent probes decreased during the cure of the epoxy resin or methyl methacrylate, these fluorescent probes can be used for monitoring the polymerization reactions of epoxy resins and vinyl resins.