Controlled Radical Polymerization of Vinyl Chloride Mediated by Xanthene-9-Thione

The controlled radical polymerization (CRP) of vinyl chloride monomer (VCM), a low activity monomer with high radical reactivity, is still a true challenge. In this study, a novel CRP of VCM with high monomer conversion at 45 °C with xanthene-9-thione (XT) as mediator and bis(4-tert-butylcyclohexyl)peroxydicarbonate (TBCP) as initiator is achieved. The Mn of the produced poly(vinyl chloride) (PVC) increases slightly with increasing monomer conversion and could be mediated in the range from 6k to 12k by simply changing the molar ratio of TBCP/XT while the dispersity maintains around 2.0. The fidelity of XT dormant groups of PVC-XT is about 60–80% and depends on the ratio of TBCP/XT. With the as-prepared PVC-XT as macroinitiator, block copolymerizations of methyl methacrylate (MMA), n-butyl acrylate (BA), and styrene (St) are carried out and the PVC-b-PMMA, PVC-b-PBA, and PVC-b-PSt block copolymers have been synthesized successfully.