Saito Tsuguyuki, Nishiyama Yoshiharu, Putaux Jean-Luc, Vignon Michel, Isogai Akira
Centre de Recherches sur les Macromolécules Végétales, CNRS/ICMG/UJF, BP 53, F-38041 Grenoble Cedex 9, France.
Biomacromolecules. 2006 Jun;7(6):1687-91. doi: 10.1021/bm060154s.
Never-dried native celluloses (bleached sulfite wood pulp, cotton, tunicin, and bacterial cellulose) were disintegrated into individual microfibrils after oxidation mediated by the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical followed by a homogenizing mechanical treatment. When oxidized with 3.6 mmol of NaClO per gram of cellulose, almost the totality of sulfite wood pulp and cotton were readily disintegrated into long individual microfibrils by a treatment with a Waring Blendor, yielding transparent and highly viscous suspensions. When observed by transmission electron microscopy, the wood pulp and cotton microfibrils exhibited a regular width of 3-5 nm. Tunicin and bacterial cellulose could be disintegrated by sonication. A bulk degree of oxidation of about 0.2 per one anhydroglucose unit of cellulose was necessary for a smooth disintegration of sulfite wood pulp, whereas only small amounts of independent microfibrils were obtained at lower oxidation levels. This limiting degree of oxidation decreased in the following order: sulfite wood pulp > cotton > bacterial cellulose, tunicin.
未干燥的天然纤维素（亚硫酸盐漂白木浆、棉花、被囊纤维素和细菌纤维素）在2,2,6,6-四甲基哌啶-1-氧基（TEMPO）自由基介导的氧化作用下，随后经过均质机械处理，被分解成单个微纤丝。当每克纤维素用3.6 mmol的NaClO氧化时，几乎所有的亚硫酸盐木浆和棉花通过韦林氏搅拌器处理后很容易分解成长的单个微纤丝，产生透明且高粘性的悬浮液。通过透射电子显微镜观察时，木浆和棉花微纤丝呈现出3-5 nm的规则宽度。被囊纤维素和细菌纤维素可以通过超声处理分解。对于亚硫酸盐木浆的顺利分解，纤维素每一个脱水葡萄糖单元的整体氧化度约为0.2是必要的，而在较低氧化水平下只能获得少量独立的微纤丝。这种极限氧化度按以下顺序降低：亚硫酸盐木浆＞棉花＞细菌纤维素、被囊纤维素。
