PHOTOPOLYMERIZATION OF POLYFUNCTIONAL ACRYLATES AND METHACRYLATE MIXTURES - CHARACTERIZATION OF POLYMERIC NETWORKS BY A COMBINATION OF FLUORESCENCE SPECTROSCOPY AND SOLID-STATE NUCLEAR-MAGNETIC-RESONANCE

Fluorescence spectroscopy and solid state NMR methods were used to elu cidate the detailed molecular structure of poly(meth)acrylate networks . Both techniques can be employed on identical samples and give comple mentary information. In this study a series of diacrylates, a series o f dimethacrylates, and 1:1 mixtures of the triacrylate TMPTA with diac rylates (DA's) or dimethacrylates (DMA's), respectively, was investiga ted. Fluorescence spectroscopy was performed, using the shift in the f luorescence maximum of 4-(dimethylamino)-4'-nitrostilbene (1), a charg e transfer probe. This probe monitors both the rigidity and the polari ty of the medium in which it is incorporated, CPMAS(13)C NMR spectrosc opy was employed monitoring the relaxation times, T-1, of carbon atoms from the main chains and pendant groups, determining cross-link densi ties, and measuring T-1 rho(H-1) values. With these techniques informa tion about the mobility of individual atoms and the homogeneity of the polymeric networks is obtained.