Fluorescence and Photosensitizing Behavior of N-(p-Phenoxyphenyl)methacrylamide and Its Polymer

A novel acrylic monomer bearing aromatic ethereality group N-(p-phenoxy-phenyl) methacrylamide(MAPOA) was synthesized and polymerized. The fluorescence spectra of MAPOA and its polymer were studied, showing that the polymer displays a stronger fluorescence than its monomer at the same chromophore concentration. The fluorescence of P(MAPOA) was quenched by adding electron deficiency monomers such as MMA, AN etc.. It is another example of showing the "fluorescence structural self-quenching effect" as we reported previously, from which it is demonstrated again that this phenomenon is not an accidental one but a common effect for acrylic monomers bearing electon-donating chromophores. The photopolymerization of AN sensitized by MAPOA and P(MAPOA) was studied. The kinetic equation of the polymerization was obtained and represented as follows: Rp∝MAPOA]0.38×AN]0.78,Rp∝P(MAPOA)]0.33×AN]0.71The overall activation energies were determined to be Ea=24.22 kJ/mol(MAPOA) and Ea=26.31 kJ/molP(MAPOA)] respectively. The fluorescence analysis of the resulted P(AN) showed that the sensitizer also entered into the P(AN) chains. A mechanism of the formation of a charge transfer complex and free radical initiation was suggested for the photopolymerization of AN sensitized by MAPOA and P(MAPOA).