Synthesis of hydrophilic poly(vinyl ether)s and their application for separation media design

Abstract

Poly(2-acetoxyethyl vinyl ether (AcOVE)) and poly(2-acetoxyethyl vinyl ether- co-2-vinyloxyethyl phthalimide) were synthesized by traditional cationic polymerization, typically at −20°C in toluene with BF 3O(C 2H 5) 2 as initiator, to give polymers with degrees of polymerization (Dp) in the range of 600–1100. In addition, poly(AcOVE) was polymerized by controlled cationic polymerization at 0°C with molecular weights in a predetermined fashion. The Dp's were calculated from Dp = [M] 0 [I] 0 and typical values were 5, 10, 100 and 200. The molecular weight values obtained for a theoretical Dp = 200, were for poly(2-acetoxyethyl vinyl ether), M n = 19,200, M w = 22,700 and polydispersity = 1.2, as determined by GPC. The deprotected hydrophilic polymers, poly(2-hydroxyethyl vinyl ether) and poly(2-hydroxyethyl vinyl ether- co-2-aminoethyl vinyl ether), were used for the preparation of novel gel filtration media as well as new anion exchangers. In the case of gel filtration, poly(2-hydroxyethyl vinyl ether) was attached to a beaded agarose matrix (34 μm), i.e. Sepharose® HP. It was shown that the attachment of the poly(vinyl ether) affected the selectivity. In gel filtration of selected biomolecules, the poly(vinyl ether) modified agarose matrix showed performance characteristics comparable to the reference used, i.e. Superdex® 30 prep grade. In addition the poly(vinyl ether)s were shown to be stable in a wide pH-range. The stability was confirmed by the conclusion that no changes in molecular weight were observed after treatment with 0.1 M HCl (pH = 1) or 0.01 M NaOH (pH = 12) for six weeks at 40°C. For the preparation of anion-exchanger media, the beads containing poly(2-hydroxyethyl vinyl ether) was further modified with a quaternary ammonium group, to produce a separation media having a high dynamic binding capacity for bovine serum albumin (BSA).