Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5203386 | Polymer Degradation and Stability | 2010 | 5 Pages |
Abstract
The effect of chemical structures of TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxy radical) derivatives and its analogous compounds on oxidation efficiency of C6 primary hydroxyls of wood cellulose was investigated using the NaClO/NaBr system at pH 10. Because the oxidation takes place selectively on the surfaces of cellulose microfibrils, individualized and surface-oxidized cellulose nanofibrils can be obtained by simple mechanical treatment in water, when sufficient amounts of carboxylate groups are formed homogeneously in cellulose microfibrils. 4-acetamide-TEMPO and 4-methoxy-TEMPO showed efficient catalytic behavior with short reaction times (<4Â h) and high carboxylate contents (>1.1Â mmol/g) in oxidation of wood cellulose, comparable to TEMPO. Correspondingly, these TEMPO derivatives as well as TEMPO gave high nanofibril yields >56%. On the other hand, the use of 4-hydroxy-TEMPO and 4-oxo-TEMPO resulted in the lowest efficiency in oxidation: oxidation times >24Â h, carboxylate contents <0.3Â mmol/g, and individualized and surface-oxidized nanofibril yields <2%.
Related Topics
Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Shinichiro Iwamoto, Weihua Kai, Takuya Isogai, Tsuguyuki Saito, Akira Isogai, Tadahisa Iwata,