Poly(vinyl alcohol) modification with n‐alkyl chloroformates

This work deals with the modification reaction of poly(vinyl alcohol) with n‐alkyl chloroformates using pyridine as catalyst. The structure of the modified polymers was determined by means of IR, 1H and 13C‐NMR spectroscopy as well as by chemical analysis. Vinyl alcohol‐vinyl n‐alkyl carbonate copolymers were obtained. The presence of cyclic carbonates has not been observed. It has been found a linear dependence of reaction rate on polymer, n‐alkyl chloroformates, and pyridine concentrations, respectively. The activation energy found was of 15.4 kcal/mol. The water absorbed in the copolymers made it reasonable to conclude that the hydrophilic character of the copolymers decreased progressively when either the carbonate groups content or the side chain length increased. Water insoluble alcohol‐vinyl n‐alkyl carbonate copolymers were hydrolyzed in an alkaline medium. They were found to recover their solubility in water after a certain hydrolysis extent was reached.