Assembling and Redispersibility of Rice Straw Nanocellulose: Effect of tert-Butanol
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- 作者：Feng Jiang ; You-Lo Hsieh
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2014
- 出版时间：November 26, 2014
- 年：2014
- 卷：6
- 期：22
- 页码：20075-20084
- 全文大小：706K
- ISSN：1944-8252
文摘
Self-assembling of sulfuric-acid-hydrolyzed cellulose nanocrystals (CNCs, 6.4 nm wide) and TEMPO oxidized cellulose nanofibrils (CNFs, 2.1 nm wide) from aqueous suspensions was induced by rapid freezing (鈭?96 掳C, 10 min) and slow lyophilization (鈭?0 掳C, 0.05 mbar, 2 days). The assembled structures contain submicron (200鈥?00 nm) wide and tens of micrometer long fibers at up to 0.1鈥?.5% and 0.01鈥?.05%, the critical fiber-to-film transformation concentrations for CNCs and CNFs, respectively. The assembled fiber widths were significantly reduced to 鈭?0 nm, that is, by 1 order of magnitude, when 10% of the aqueous media was replaced with tert-butanol. Further increasing tert-butanol contents in the media to 93/7 (CNCs) and 50/50 (CNFs) tert-butanol/water, both at 0.1% nanocellulose concentration, reduced longitudinal assembling for CNCs and lateral assembling for CNFs as well as increased critical fiber-to-film transformation concentration for CNFs. While all assembled structure could be redispersed in water, those from tert-butanol/water could also be easily redispersed in DMF aided with brief 2 min ultrasonication. None of the assembled structures could be redispersed in the lower dielectric constant ethanol, acetone or chloroform.