Cyclodextrins in polymer synthesis: free radical polymerization of cyclodextrin complexes with oxazoline-functionalized vinyl monomers as guest molecules in aqueous medium

Abstract

The synthesis of five new oxazoline functionalized vinyl monomers N-[4-(4′,5′-dihydrooxazol-2-yl)phenyl]acrylamide (3 a), N-[4-(4′,5′-dihydrooxazol-2-yl)phenyl]-2-methylacrylamide (3 b), N-{10-[4-(4′,5′-dihydrooxazol-2-yl)phenylcarbamoyl]decyl}-2-acrylamide (5 a), N-{10-[4-(4′,5′-dihydrooxazol-2-yl)phenylcarbamoyl]decyl}-2-methylacrylamide (5 b) and N-[4-(4′,5′-dihydrooxazol-2-yl)-phenyl]-4-vinylbenzamide (7) is described. With an equimolar amount of 2,6-dimethyl-β-cyclodextrin (DMCD) these monomers formed hydrophilic inclusion complexes 3 a,b-DMCD, 5 a,b-DMCD and 7-DMCD. These complexes were polymerized radically in an aqueous medium. Resulting polymers P-(3 a, b), P-(5 a, b) and P-(7) precipitated during the polymerization due to unthreading of the cyclodextrin from the growing polymer chain. The remaining oxazoline moiety offers possibilities of further modification of the polymers, e. g. grafting in a cationic ring opening polymerization with commercially available alkyloxazolines.