| 초록 |
Cashew(Anacardium occidentale L.) nut shell liquid (CNSL) is a unique natural source for unsaturated long-chain phenol. Obtained as a byproduct of the cashew industry, this renewable material has wide applications in the form of brake linings, surface coatings, paints, and varnish. Enzymatic polymerizations by biocatalysis have received much attention as new methodology of polymer synthesis. Peroxidases induced the oxidative polymerization of phenol derivatives under mild reaction conditions to produce a new class of polyphenol. In this work, enzymatic copolymerization of cardanol and cardol was examined under various reaction conditions. Soybean peroxidase catalyzed the oxidative copolymerization of cardanol and cardol to give an oily, soluble polymer under appropriate reaction condition. The copolymers yield and molecular weight were found to be dependent on enzyme activity of soybean peroxidae, solvent and buffer systems, and concentration of hydrogen peroxide. GPC, NMR and IR analysis of the products showed that phenolic moieties were polymerized and the carbon-carbon unsaturated group in the side chain of cardanol and cardol were not reacted during the polymerization. The copolymers were subjected to the hardening by cobalt naphthenate catalyst, giving a crosslinked tough film. The pencil scratch hardness of copolymers reached to 5H, which is enough hard for industrial uses. The present method can be regarded as an environmentally benign process of polymer coating.
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