Living Cationic Polymerization of 2-Chloroethyl Vinyl Ether with Iodine and Hydrogen Iodide/Iodine Initiators

Abstract

This paper is concerned with the living cationic polymerization of 2-chloroethyl vinyl ether (CEVE). Living poly(CEVE) of a nearly monodisperse molecular weight distribution (MWD) (Mw/Mn\\lesssim1.1) was obtained in toluene at −40°C with a mixture of hydrogen iodide (HI) and iodine as initiating system. The number-average molecular weight (Mn) of the polymer increased proportionally to CEVE conversion, while the MWD remained nearly monodisperse throughout the reaction. An excess amount of HI over iodine was needed to achieve this living process. The polymerization at −15°C by the HI/I2 initiator in toluene or CCl4 also led to living polymers with Mn directly proportional to conversion, but their MWD was slightly broader (Mw/Mn=1.2—1.3). Iodine alone as initiator resulted in long-lived (but not perfectly living) polymers at −15°C in toluene. Although the Mn of the polymers increased proportionally to conversion, their MWD was much broader Mw/Mn=1.4—1.6 than with the HI/I2 initiator, indicating a slower initiation by this initiator.