Complete nanofibrillation of cellulose prepared by phosphorylation

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• 作者：Yuichi Noguchi ; Ikue Homma ; Yusuke Matsubara
• 关键词：Cellulose nanofiber ; Nanocellulose ; Phosphorylation ; High yield ; High transparency ; High viscosity
• 刊名：Cellulose
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：24
• 期：3
• 页码：1295-1305
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Bioorganic Chemistry; Physical Chemistry; Organic Chemistry; Polymer Sciences;
• 出版者：Springer Netherlands
• ISSN：1572-882X
• 卷排序：24

文摘

In this work, we prepared phosphorylated pulp with a phosphorous content of 1.23 mmol/g by adding an aqueous solution of NH₄H₂PO₄ and urea to softwood pulp sheets followed by drying and curing with hot air and obtained cellulose nanofibers (CNFs) with a uniform width of 3–4 nm in approximately 100% gravimetric yield by high-pressure homogenization of the phosphorylated pulp slurry. After phosphorylation, no significant decrease in the pulp recovery ratio was observed, and the viscosity-average degree of polymerization of phosphorylated pulp was almost equal to that of the original pulp. In addition, the crystal structure and crystallinity index were almost unchanged during phosphorylation. The obtained phosphorylated CNF dispersion was highly transparent, and the maximum total light transmittance was nearly 100% when the CNF content was 0.2 wt%. The maximum viscosity of the CNF dispersions was nearly 10–100 times greater than that of conventional thickeners. Furthermore, we found that not only insufficient but also excessive phosphorylation negatively affected the gravimetric yield, transparency and viscosity.