Photoresponsive Functionalized Vinyl Cinnamate Polymers: Synthesis and Characterization

A series of functionalized vinyl cinnamate monomers were synthesized by the reaction of hydroxyethylmethacrylate and various substituted cinnamoyl chlorides. Electron donating and accepting functional groups such as −OCH3, −Cl and −NO2 were introduced at the para position of cinnamoyl chloride. Homopolymerization of the synthesized monomers were carried out in dimethylformamide using azobisisobutyronitrile as a free radical initiator at 80°C for 12h. The structures of the synthesized monomers and their polymers were characterized using Fourier transform infrared (FTIR), 1H and 13C nuclear magnetic resonance spectroscopic techniques. Solid-state crosslinking of the above photosensitive polymers was studied by UV and FTIR spectroscopic techniques. The effects of various functional groups and the addition of sensitizer (benzophenone) on the photocrosslinking nature of the polymers were studied. The mechanism of photocrosslinking is a (2+2)π electron cycloaddition and not cis–trans isomerization in the functionalized polyvinylcinnamates. © 1997 SCI