期刊
CELLULOSE
卷 27, 期 2, 页码 657-676出版社
SPRINGER
DOI: 10.1007/s10570-019-02789-z
关键词
One-step synthesis; Nanocrystalline cellulose; Ammonium persulfate; Swelling; Oxidation; Spindle-shaped helical structure; Chiral self-assembly
资金
- National Natural Science Foundation of China [21566014, 21766016]
- China Postdoctoral Science Foundation [2019M653845XB]
- Postdoctoral Research Funding of Kunming University of Science and Technology [10988880]
- Yunnan Province Postdoctoral Orientation Training Funding
- Yunnan Province Postdoctoral Research Funding
A single-step ammonium persulfate (APS)-assisted swelling, followed by oxidation, can prepare nanocrystalline cellulose (NCC) from cotton linters. The APS-swelling is the critical step in the process, and the effects of swelling time, temperature and solid-liquid ratios were thoroughly investigated. The optimal conditions for NCC preparation were a swelling time of 3.0 h, a swelling temperature of 25 degrees C, and a solid-liquid ratio of 1:50. Upon heating at 60 degrees C, the persulfate enters the amorphous region of the cellulose and produces active SO4 center dot- and H2O2, which effectively attack the two-phase structure of cellulose and oxidize the -OH group at the C-6 position. The swelling temperature of 25 degrees C plays a crucial role in breaking the hydrogen bonds between the molecular chains of cellulose. It permits the preparation of NCC with a high yield and crystallinity index. The crystalline structure of cellulose I-beta did not change after APS swelling and oxidation. The atomic force microscopic analysis confirmed the formation of spindle-shaped particles with a helical structure. Upon natural evaporation of the NCC suspension, brittle films were obtained, which exhibited a left-hand layered structure and high iridescence with a fingerprint-texture. These materials can be applied as strength additives and chiral templates. [GRAPHICS] .
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