Multifunctional Poly(vinyl ethers) by Controlled Cationic Polymerisation in a Fluorinated Solvent

Abstract

The living nature of the cationic polymerisation of butyl vinyl ether (BVE) in the fluorinated solvent 1,1,2-trichloro trifluoroethane was studied, using the initiating system composed of ethyl aluminium dichloride (EtAlCl 2 ) as the activator and 1-butoxyethyl acetate (BEA) as the initiator. BVE homopolymerises in a seemingly living fashion at T≤0°C in the presence of 1,4-dioxane (DO) as a stabilising Lewis base, although the fluorinated solvent slows down the polymerisation appreciably. Less than quantitative reinitiation has been observed when a second BVE feed was added to the living macrocation at nearly quantitative monomer conversion. The functional monomers 2-chloroethyl vinyl ether (CLEVE), 3-cyano-3-ethoxycarbonylpropyl vinyl ether (CNEVE) and 1H,1H,2H,2H-perfluorodecyl vinyl ether (XFDVE) were submitted to polymerisation under the same conditions that allow to achieve a quasi-living BVE polymerisation. CLEVE gave a homopolymer with relatively narrow molecular-weight distribution (MWD), while efficient polymerisation of XFDVE was only achieved with BF 3 etherate as the initiator. Copolymerisation of the various functional vinyl ethers with BVE takes place in a more controlled fashion, yielding products with narrow MWD index (M w /M n = 1.2-1.35), at moderate functional vinyl ether conversions. Block polymers could be synthesised from poly(BVE) living macrocations; these are probably characterised by a hybrid structure, consisting of a pure BVE block and a second block of BVE-functional vinyl ether copolymer.