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| Content Provider | Springer Nature Link |
|---|---|
| Author | Takaichi, Satoshi Saito, Tsuguyuki Tanaka, Reina Isogai, Akira |
| Copyright Year | 2014 |
| Abstract | Never-dried 2,2,6,6,-tetramethylpiperidinyl-1-oxyl (TEMPO)-oxidized wood celluloses (TOCs) with carboxylate contents of 1.0–1.7 mmol/g can be converted to TEMPO-oxidized cellulose nanofibrils (TOCNs) with homogeneous widths of ≈3 nm by mechanical disintegration treatment in water. However, oven-dried TOCs have low nanodispersibility in water. In this study, when TOC was reduced with NaBH4 under suitable conditions, almost all C6-aldehydes and C2/C3 ketones present in the TOCs were converted to hydroxyl groups. The NaBH4-reduced TOCs had sufficiently high nanodispersibility (similar to that of never-dried TOCs) in water even after oven drying at 105 °C for 3 h. Thus, interfibrillar hemiacetal linkages are probably formed between hydroxyl groups and either C6-aldehydes or C2/C3 ketones present on the crystalline microfibril surfaces of TOCs during heating, resulting in low nanodispersibility. The heat-induced discoloration of TOCs can also be avoided by using NaBH4-reduced TOCs. Heating of the oven-dried TOCs in water at 80 °C for 0.5–3 h improves their nanodispersibility, presumably because the interfibrillar hemiacetal linkages formed by oven drying are broken during the hot-water treatment. A semi-quantitative method to determine C6-aldehydes and C2/C3 ketones present in dried TOCs is proposed, in which the specific UV absorbance spectra of TOCN films heated at 105 °C for 3 h are used. The presence of C6-aldehydes and C2/C3 ketones in TOCs can be determined by UV absorption peaks of the TOCN films at ≈260 and ≈290 nm, respectively. |
| Starting Page | 4093 |
| Ending Page | 4103 |
| Page Count | 11 |
| File Format | |
| ISSN | 09690239 |
| Journal | Cellulose |
| Volume Number | 21 |
| Issue Number | 6 |
| e-ISSN | 1572882X |
| Language | English |
| Publisher | Springer Netherlands |
| Publisher Date | 2014-09-16 |
| Publisher Place | Dordrecht |
| Access Restriction | One Nation One Subscription (ONOS) |
| Subject Keyword | Carbonyl group NaBH4 reduction Nanodispersibility 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) TEMPO-oxidized cellulose Bioorganic Chemistry Physical Chemistry Organic Chemistry Polymer Sciences |
| Content Type | Text |
| Resource Type | Article |
| Subject | Polymers and Plastics |
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