Graft copolymers with complex polyether structures: Poly(ethylene oxide)-graft-poly(isobutyl vinyl ether) by combination of living anionic and photoinduced cationic graft polymerization

A novel polymerization mechanism transformation strategy, involving anionic ring-opening polymerization and photoinduced cationic polymerization, is successfully applied for the synthesis of poly(ethylene oxide)-graft- poly(isobutyl vinyl ether) (PEO-g-PIBVE). First, poly(ethylene oxide-co-ethoxyl vinyl glycidyl ether) [P(EO-co-EVGE)] is synthesized by living anionic polymerization. The vinyl moieties of the functional PEO-based polymer are converted to the hydrogen iodide adduct by photolysis of diphenyliodonium iodide, monitored using NMR spectroscopy. A modified mode of Lewis acid-catalyzed living cationic polymerization is performed as a "grafting from" method to generate PIBVE segments grafted onto the PEO main chain. Both the intermediates and the final graft copolymers are characterized by gel-permeation chromatography (GPC) and ¹H NMR analysis. A novel polymerization-mechanism transformation strategy, involving anionic ring-opening polymerization and photoinduced cationic polymerization, is successfully applied for the synthesis of poly(ethylene oxide)-graft-poly(isobutyl vinyl ether) (PEO-g-PIBVE). Vinyl moieties of a PEO-based polymer, which is synthesized by anionic polymerization, are readily converted to the hydrogen iodide adduct by photolysis of diphenyliodonium iodide. Addition of this adduct to the polymerization solution simply yields PEO-g-PIBVE.