Synthesis,characterization and hydrolysis of poly[styrene-co-(6-methylene-1,4-oxathiepane-7-one)] and poly[styrene-co-(6-methylene-5-methyl-1,4-oxathiepane-7-one)]

Vinylic-type polymers bearing ester groups inside the polymer backbone have been synthesized by free radical copolymerization of styrene (St) and 6-methylene-1,4-oxathiepane-7-one (MOTPO) or 6-methylene-5-methyl-1,4-oxathiepane-7-one (MMOTPO). The addition-fragmentation ring-opening polymerization of both MOTPO and MMOTPO leads to the formation of ester linkages located inside the vinylic polymer backbone. A strong decrease of the molar mass of the copolymer has been observed when the copolymers were dissolved in a mixture of THF and water in the presence of sodium hydroxide. This decrease can be attributed to the hydrolysis of the ester linkages, as followed by size exclusion chromatography (SEC). The molar mass of the degraded polymer samples was correlated with the number of ester linkages in the backbone, showing that only a fraction of these ester groups have been hydrolyzed.