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Facile Post-Carboxymethylation of Cellulose Nanofiber Surfaces for Enhanced Water Dispersibility
| Title: | Facile Post-Carboxymethylation of Cellulose Nanofiber Surfaces for Enhanced Water Dispersibility |
| Authors: | Kono, Hiroyuki Browse this author | | Tsukamoto, Eiki Browse this author | | Tajima, Kenji Browse this author →KAKEN DB |
| Keywords: | Carbon namomaterials | | Nanofibers | | Fibers | | Substitution reactions | | Cellulose |
| Issue Date: | 2022 |
| Publisher: | American Chemical Society |
| Journal Title: | ACS Omega |
| Volume: | 6 |
| Issue: | 49 |
| Start Page: | 34107 |
| End Page: | 34114 |
| Publisher DOI: | 10.1021/acsomega.1c05603 |
| Abstract: | To improve the water dispersibility of cellulose nanofibers without deteriorating the physical properties, it is necessary to develop methods that can selectively modify fiber surfaces. Herein, the reaction conditions for carboxymethylation of the surface of nanofibrillated bacterial cellulose were optimized using chloroacetic acid as an etherification agent. Carboxymethylation in a high-concentration alkaline solution (>5 wt %) in the presence of isopropanol caused the mercerization and carboxymethylation of not only the nanofiber surface but also the cellulose crystals within the nanofiber, resulting in nanofiber swelling and an increase in fiber width. In contrast, with a dilute alkaline aqueous solution (3 wt %), the nanofiber surface was successfully carboxymethylated without changing the inner structure. Furthermore, the morphology was not affected by the carboxymethylation reaction, and no fiber swelling occurred under these reaction conditions. When the substitution reaction proceeded only on the nanofiber surface, the maximum degree of substitution (i.e., the average number of carboxymethyl groups substituted per anhydroglucose residue in cellulose) was 0.091. After surface modification, the nanofibers became more negatively charged, which improved the dispersibility in water through electrostatic repulsion, resulting in a drastic increase in the transparency of the nanofiber dispersion. This method provides a general approach for the surface modification of cellulose nanofibers to increase water dispersibility. |
| Type: | article |
| URI: | http://hdl.handle.net/2115/84780 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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