Living cationic polymerization of ethyl 2‐(vinyloxy)ethoxyacetate: A vinyl ether with an ether and an ester function in the pendant

Abstract

AbstractEthyl 2‐(vinyloxy)ethoxyacetate (4; CH2CHOCH2CH2OCH2COOC2H5), a vinyl ether having both carboxylic acid ester and oxyethylene unit in its pendant, afforded well‐defined living polymers when polymerized by the hydrogen iodide/iodine (HI/I2) initiating system in toluene at −40°C. The polymers possessed a narrow molecular weight distribution (Mw/Mn ≤ 1.15), and their molecular weight (Mn) increased proportionally to monomer conversion or the molar ratio of the monomer to hydrogen iodide. The polymer molecular weight also increased upon addition of a fresh feed of the monomer to a completely polymerized reaction mixture. Polymers of high molecular weights (Mn > 5 × 105) and broad molecular weight distributions were obtained by BF3OEt2 in toluene at −40°C. Polymerization rate of 4 with HI/I2 is ca. 100 times greater than that of the corresponding alkyl vinyl ether, and thus 4 was found to be one of the most reactive vinyl ethers thus far studied. Alkaline hydrolysis of the pendant ester groups of the polymers gave a vinyl ether‐based polymeric carboxylic acid 6 with a narrow molecular weight distribution.