Cationic polymerization of vinyl ether with a benzoate pendant: The formation of long-lived polymers and the identification of side reactions

The cationic polymerization of 2-[4-(methoxycarbonyl)phenoxy] ethyl vinyl e ther, a vinyl ether with a benzoate pendant, was carried out with an HCl/Zn Cl2 initiating system in methylene chloride at -15 degreesC. The polymeriza tion proceeded with living/long-lived propagating species to produce polyme rs with controlled molecular weights and relatively narrow molecular weight distributions (weight-average molecular weight/number average molecular we ight less than or equal to similar to1.4), despite the formation of a small amount of oligomeric products during the polymerization. The structural an alysis showed that the lowest molecular weight oligomer had the structure C H3CH(OCH2CH2OC6H4COOCH3)OCH2CH2OC6H4COOCH3. The oligomer was formed by the reaction of the monomeric propagating species with the alcohol produced by the side reaction of the active species with water as an impurity during th e early stage of polymerization. (C) 2000 John Wiley & Sons.