PHOTOCHEMICAL-REACTIONS OF POLYMERS BEARING CHALCONE RESIDUES

Photosensitive polymers based on pendent chalcone moieties were prepared directly by radical polymerization of vinyl-chalcone monomers. The monomers were synthesized by the esterification reactions of the hydroxyl groups of 4- and 4'-hydroxychalcones with methacryloyl chloride. The monomers (4- and 4'-(methacryloyloxy)chalcones) were polymerized to give the corresponding homo- and co-polymers containing different ratios of p-nitrophenyl methacrylate as photosensitizer group. Investigation of the photosensitivities of the chalcone polymers was carried out through study of the photochemical reactions on exposure to UV light and measuring the changes in UV spectra before and after irradiation. The results obtained from the disappearance rates of the C=C bonds indicate that the photoreactivities of the polymers are largely affected by the position of thc attachment of the chalcone to the polymer backbone and by the concentration of the photosensitizer group.