Individualization of Nano-Sized Plant Cellulose Fibrils by Direct Surface Carboxylation Using TEMPO Catalyst under Neutral Conditions

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• 作者：Tsuguyuki Saito ; Masayuki Hirota ; Naoyuki Tamura ; Satoshi Kimura ; Hayaka Fukuzumi ; Laurent Heux ; Akira Isogai
• 刊名：Biomacromolecules
• 出版年：2009
• 出版时间：July 13, 2009
• 年：2009
• 卷：10
• 期：7
• 页码：1992-1996
• 全文大小：206K
• 年卷期：v.10,no.7(July 13, 2009)
• ISSN：1526-4602

文摘

A new catalytic oxidation using 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) and NaClO is applied to hardwood cellulose in water at 60 °C and pH 6.8 with NaClO₂ used as a primary oxidant. The oxidized celluloses with carboxylate content of approximately 0.8 mmol/g were convertible to highly crystalline and individual fibrils 5 nm in width and at least 2 μm in length by disintegration in water. The oxidized celluloses had no aldehyde groups, and high degrees of polymerization of more than 900. Solid-state ¹³C NMR and X-ray analyses revealed that the C6 carboxylate groups formed are selectively present on the crystalline fibril surfaces at high densities. Films prepared from the dispersions were transparent and flexible, and exhibited a high tensile strength of 312 MPa even at a low density of 1.47 g/cm³.