Thermal Mobility of 尾-O-4-Type Artificial Lignin

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• 作者：Yasumitsu Uraki ; Yusuke Sugiyama ; Keiichi Koda ; Satoshi Kubo ; Takao Kishimoto ; John F. Kadla
• 刊名：Biomacromolecules
• 出版年：2012
• 出版时间：March 12, 2012
• 年：2012
• 卷：13
• 期：3
• 页码：867-872
• 全文大小：354K
• 年卷期：v.13,no.3(March 12, 2012)
• ISSN：1526-4602

文摘

Several lignin model polymers and their derivatives comprised exclusively of 尾-O-4 or 8-O-4鈥?interunitary linkages were synthesized to better understand the relation between the thermal mobility of lignin, in particular, thermal fusibility and its chemical structure; an area of critical importance with respect to the biorefining of woody biomass and the future forest products industry. The phenylethane (C6鈥揅2)-type lignin model (polymer 1) exhibited thermal fusibility, transforming into the rubbery/liquid phase upon exposure to increasing temperature, whereas the phenylpropane (C6鈥揅3)-type model (polymer 2) did not, forming a char at higher temperature. However, modifying the C纬 or 9-carbon in polymer 2 to the corresponding ethyl ester or acetate derivative imparted thermal fusibility into this previously infusible polymer. FT-IR analyses confirmed differences in hydrogen bonding between the two model lignins. Both polymers had weak intramolecular hydrogen bonds, but polymer 2 exhibited stronger intermolecular hydrogen bonding involving the C纬-hydroxyl group. This intermolecular interaction is responsible for suppressing the thermal mobility of the C6鈥揅3-type model, resulting in the observed infusibility and charring at high temperatures. In fact, the C纬-hydroxyl group and the corresponding intermolecular hydrogen bonding interactions likely play a dominant role in the infusibility of most native lignins.