Enzymatic Polymerization - Development of New Area in Polymer Chemistry -

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Polymerizations catalyzed by enzymes ("enzymatic polymerizations") have been developed. First chemical synthesis of chitin was achieved by chitinase-catalyzed polymerization of a chitobiose oxazoline derivative. Formation of plate-like single crystals of α-chitin was observed. The crystals aggregated, growing up to spherulites. Non-natural polysaccharides, alternatingly 6-O-methylated cellulose and a cellulose-xylan hybrid polymer (polysaccharide having a glucose-xylose repeating unit), were enzymatically synthesized.Systematic investigation on lipase-catalyzed ring-opening polymerization of lactones showed specific enzymatic catalysis in the relationships between the monomer ring-size and polymerizability. Substituted lactones were enantioselectively copolymerized with non-substituted lactones to give optically active polymers. Facile synthesis of end-functionalized polyesters was achieved by using lipase as catalyst. The polymerization of dicarboxylic acid and glycol proceeded even without solvents. The regioselective polymerization of glycerol with divinyl esters produced the reactive polyesters.As to enzymatic synthesis of polyaromatics, oxidoreductase enzymes and their model complexes induced the regioselective polymerization of phenols. A solubie polyphenol was first synthesized by peroxidase-catalyzed polymerization of phenol in an aqueous methanol and the polymer structure could be controlled by changing the solvent composition. Crosslinkable polyphenols having methacryloyl and ethynyl groups were enzymatically synthesized, which were subjected to thermal and photochemical hardening. Urushiol derivatives were cured by laccase catalyst to give the brilliant film with high gloss surface.