Homogeneous suspensions of individualized microfibrils from TEMPO-catalyzed oxidation of native cellulose
Homogeneous suspensions of individualized microfibrils from TEMPO-catalyzed oxidation of native cellulose
复制标题
DOI：
10.1021/bm060154s
复制
发表时间：
2006-06-01
影响因子：
6.2
通讯作者：
Isogai, Akira
中科院分区：
文献类型：
--
作者：
Saito, Tsuguyuki;Nishiyama, Yoshiharu;Isogai, Akira
从未干燥的天然纤维素（漂白的亚硫酸盐木浆，棉花，衣蛋白，和细菌纤维素）分解成单独的微纤维后，介导的氧化由2，2，6，6-四甲基哌啶-1-氧基（克里思）自由基，然后通过机械处理。当用每克纤维素3.6 mmol的NaClO氧化时，几乎全部的亚硫酸盐木浆和棉通过用Waring Blendor处理而容易地分解成长的单独的微纤维，产生透明且高粘度的悬浮液。当通过透射电子显微镜观察时，木浆和棉微纤丝表现出3-5 nm的规则宽度。超声可使衣膜素和细菌纤维素分解。每一个脱水葡萄糖单元的纤维素的约0.2的散装程度的氧化是必要的亚硫酸盐木浆的顺利解体，而只有少量的独立的微纤维，在较低的氧化水平获得。这种极限氧化程度的顺序为：亚硫酸盐木浆>棉花>细菌纤维素、衣素。
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.