| Research Abstract |
At first, a plasticization method for cellulose acetates(CAs) that is based on the reaction with dibasic acid anhydrides and monoepoxide during melt processing was developed. This reactive melt-processing method allowed the preparation of biodegradable cellulose plastics using practical process conditions. During the processing, grafted oligoesters and the homo-oligoesters were formed. These homo-oligoesters were often migrated from inside to the surface within the moldings. It was proved that the introduction of oligoester side chains into the CA molecules resulted in an enhanced affinity between the modified CAs and homo-oligoesters, preventing the migration (bleeding). Based on these results, a method for enhancing the amount of grafting has been pursued. As the extension of the enhancement of the grafting, a plasticization method for CAs based on the selective grafting of cyclic esters has been developed The selective-garfted products could be prepared by ring-opening polymerizatio
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n in the melt state at 140 。C using tin octoate as catalyst, where CAs with remaining hydroxyl groups worked as initiator. Plasticization of CAs by this selective grafting can solve the problem of the bleeding. By using adequate reaction conditions, the grafting proceeded rapidly. The reaction products with high processibilites and physical properties could be obtained, liquefaction of biomass and three dimensionally curable resins there from have been studied. The mechanisms of the liquefaction could be elucidated in the molecular level including the practical acid catalyzed liquefaction. The thermal curabilities of the liquefied products were measured and discussed in relation to the conditions of the liquefaction and the physical properties of the molded materials were tried to be enhanced. Introductions of the functional groups into rice bran pitch were performed and the polyurethane type forms using the modified rice bran pitch as the polyol were prepared resulting in products with high qualities. Enhancement of the biodegradabilities was confirmed in the various reaction products. Less
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