Non‐transition metal‐catalyzed living radical polymerization of vinyl chloride initiated with iodoform in water at 25 °C

Abstract

AbstractNon‐transition metal‐catalyzed living radical polymerization (LRP) of vinyl chloride (VC) in water at 25–35 °C is reported. This polymerization is initiated with iodoform and catalyzed by Na2S2O4. In water, S2Odissociates into SOthat mediates the initiation and reactivation steps via a single electron transfer (SET) mechanism. The exchange between dormant and active propagating species also includes the degenerative chain transfer to dormant species (DT). In addition, the SO2released from SOduring the SET process can add reversibly to poly(vinyl chloride) (PVC) radicals and provide additional transient dormant ∼SOradicals. This novel LRP proceeds mostly by a combination of competitive SET and DT mechanisms and, therefore, it is called SET‐DTLRP. Telechelic PVC with a number‐average molecular weight (Mn) = 2,000–55,000, containing two active ∼CH2CHClI chain ends and a higher syndiotacticity than the commercial PVC were obtained by SET‐DTLRP. This PVC is free of structural defects and exhibits a higher thermal stability than commercial PVC. SET‐DTLRP of VC is carried out under reaction conditions related to those used for its commercial free‐radical polymerization. Consequently, SET‐DTLRP is of technological interest both as an alternative commercial method for the production of PVC with superior properties as well as for the synthesis of new PVC‐based architectures. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6267–6282, 2004