Saito Tsuguyuki, Kimura Satoshi, Nishiyama Yoshiharu, Isogai Akira
Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.
Biomacromolecules. 2007 Aug;8(8):2485-91. doi: 10.1021/bm0703970. Epub 2007 Jul 13.
Never-dried and once-dried hardwood celluloses were oxidized by a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated system, and highly crystalline and individualized cellulose nanofibers, dispersed in water, were prepared by mechanical treatment of the oxidized cellulose/water slurries. When carboxylate contents formed from the primary hydroxyl groups of the celluloses reached approximately 1.5 mmol/g, the oxidized cellulose/water slurries were mostly converted to transparent and highly viscous dispersions by mechanical treatment. Transmission electron microscopic observation showed that the dispersions consisted of individualized cellulose nanofibers 3-4 nm in width and a few microns in length. No intrinsic differences between never-dried and once-dried celluloses were found for preparing the dispersion, as long as carboxylate contents in the TEMPO-oxidized celluloses reached approximately 1.5 mmol/g. Changes in viscosity of the dispersions during the mechanical treatment corresponded with those in the dispersed states of the cellulose nanofibers in water.
未干燥和一次干燥的硬木纤维素通过2,2,6,6 - 四甲基哌啶 - 1 - 氧基自由基（TEMPO）介导的体系进行氧化，然后通过对氧化纤维素/水浆料进行机械处理，制备出高度结晶且分散在水中的个体化纤维素纳米纤维。当纤维素伯羟基形成的羧酸盐含量达到约1.5 mmol/g时，通过机械处理，氧化纤维素/水浆料大多转化为透明且高粘性的分散体。透射电子显微镜观察表明，分散体由宽度为3 - 4 nm、长度为几微米的个体化纤维素纳米纤维组成。只要TEMPO氧化纤维素中的羧酸盐含量达到约1.5 mmol/g，在制备分散体时，未干燥和一次干燥的纤维素之间未发现本质差异。机械处理过程中分散体粘度的变化与纤维素纳米纤维在水中的分散状态变化相对应。
