PHOTOSENSITIVE POLYMERS CONTAINING PENDENT CHALCONE MOIETIES VIA OXYETHYLENE GROUP

Vinylchalcone derivatives were prepared by the reaction of the sodium salt of 4-hydroxychalcone with 2-chloroethanol, followed by esterfication of the hydroxy groups with methacryloyl chloride in the presence of triethylamine as a base. The photosensitive monomers, 4-(methacryloyloxyethoxy)chalcone and its 4'-methyl and 4'-chloro-derivatives, have been homo- and copolymerized with p-nitrophenylmethacrylate under free radical conditions to give the copolymers containing different ratios of photosensitizer group. The photosensitivities of the polymeric chalcone derivatives were investigated through their photochemical reactions on exposure to UV light and measuring the changes in UV spectra before and after irradiation. The results of these measurements indicate that the insolubilization percentage, i.e. the rate of the double bond disappearance depends on the effects of (i) the time of exposure to UV light, (ii) the position of the substituent in the phenyl ring of the chalcone, (iii) the spacer between the active moiety and the polymer backbone, and (iv) the ratio of the photosensitizer group.