Amylose-Carrying Styrene Macromonomer and Its Homo- and Copolymers:  Synthesis via Enzyme-Catalyzed Polymerization and Complex Formation with Iodine

The objective of our research was to prepare novel conjugates between polysaccharides and vinyl polymers by applying enzymes as polymerization catalyst for polysaccharide synthesis. An approach was attained using amylose-substituted styrene macromonomers (vinylbenzyl amylose amide, VAA; the number-average degree of polymerization of amylose = 24 and 150) which were synthesized from maltopentaose-substituted styrene (VM5A) by phosphorylase-catalyzed polymerization of glucose 1-phosphate. Radical homo- and copolymerization of VAA gave an uncommon type of graft copolymers consisting of polystyrene and polyacrylamide backbones and amylose side chains of uniform length. Water-insoluble amylose was solubilized into water by incorporating VAA units into polyacrylamide main chains and also by hydroxypropylation of the amylose moieties of water-insoluble copolymers. Structural features of these graft copolymers were discussed on the basis of amylose−iodine complexation investigated by UV spectroscopy. Schematic structures of two different types of polystyrene- graft -amylose prepared via homopolymerization of VAA and via enzymatic elongation from poly(VM5A) were proposed. These amylose-carrying polyacrylamide and polystyrene prepared by applying enzyme-catalyzed polymerization are of interest as a new type of biomedical material and a well-defined model for conformational analysis.