Anionic Polymerization of Fluorinated Vinyl Monomers
Anionic addition polymerization of fluorinated vinyl monomers is described, focused mainly on monomers that were believed to be hardly polymerized under common radical polymerization conditions, such as α-trifluoromethylacrylates, hexafluoro-1,3-butadiene and α,β,β-trifluorostyrene. Anionic polymerization reactivity was enhanced by the incorporation of fluoroalkyl groups as ester moieties of acrylates and methacrylates, even though the fluoroalkyl groups were linked four or five bonds away from vinyl groups. Poly(α-trifluoromethylacrylate)s were obtained with anionic initiators of relatively low reactivity. To compare the reactivities of 18 fluorinated acrylates and methacrylates, pseudo-first-order rate constants were investigated with an organoaluminum initiator. 2,3-Addition polymerization was established in the anionic polymerization of hexafluoro-1,3-butadiene initiated by cesium compounds and excellent thermal and chemical stability of the resulting polymers was demonstrated. α,β,β-Trifluorostyrene yielded a homopolymer by initiating with lower basicity. Fluorophenylvinyl compounds generally showed similar or slightly higher reactivity compared with that of hydrocarbon analogs. There are still a number of fluorinated vinyl monomers whose behavior towards polymerization is unclear, and these vinyl monomers have to be examined individually to complete the overall picture. The knowledge obtained will allow fluorinated functional polymers to be obtained and possibly the production of stereoregular polymers by an anionic mechanism.