Potassium cinnamate reactions with photosensitizers

This article reports on the synthesis of photosensitive polymers with pendant cinnamic ester moieties and suitable photosensitizer groups by cationic copolymerizations of 2-(cinnamoyloxy)ethyl vinyl ether (CEVE) (12) with other vinyl ethers containing photosensitizer groups, and by cationic polymerization of 2-chloroethyl vinyl ether (CVE) followed by substitution reactions of the resulting poly (2-chloroethyl vinyl ether) (PCVE) with salts of photosensitizer compounds and potassium cinnamate using a phase transfer catalyst in an aprotic polar solvent. The photochemical reactivity of the obtained polymers was also investigated. 

As shown in Figure 2, PCEVE-NPVE and PCEVE-NNVE containing about 10 mol-% of pendant sensitizer groups prepared from the reactions of PCVE with potassium cinnamate and PNP or PNN have photochemical reactivity equal to PCEVE-NPVE and PCEVE-NNVE prepared from the cationic copolymerizations, however, their photochemical reactivities were changed by the contents of photosensitizer units in the copolymers. 

From all these results, it was concluded that polymers have high photochemical reactivity and high practical photosensitivity when synthesized by the cationic copolymerizations of CEVE with NNVE or NPVE, or by the reactions of PCVE with potassium cinnamate and PNN or PNP using phase transfer catalyst in DMF. 

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