Chen You Wei, Tan Thean Heng, Lee Hwei Voon, Abd Hamid Sharifah Bee
Nanotechnology & Catalysis Research Center (NANOCAT), Institute of Postgraduate Studies, University of Malaya, Kuala Lumpur 50603, Malaysia.
Materials (Basel). 2017 Jan 6;10(1):42. doi: 10.3390/ma10010042.
This study reported on the feasibility and practicability of Cr(NO₃)₃ hydrolysis to isolate cellulose nanocrystals (CNC) from native cellulosic feedstock. The physicochemical properties of CNC were compared with nanocellulose isolated using sulfuric acid hydrolysis (CNC). In optimum hydrolysis conditions, 80 °C, 1.5 h, 0.8 M Cr(NO₃)₃ metal salt and solid-liquid ratio of 1:30, the CNC exhibited a network-like long fibrous structure with the aspect ratio of 15.7, while the CNC showed rice-shape structure with an aspect ratio of 3.5. Additionally, Cr(NO₃)₃-treated CNC rendered a higher crystallinity (86.5% ± 0.3%) with high yield (83.6% ± 0.6%) as compared to the H₂SO₄-treated CNC (81.4% ± 0.1% and 54.7% ± 0.3%, respectively). Furthermore, better thermal stability of CNC (344 °C) compared to CNC (273 °C) rendered a high potential for nanocomposite application. This comparable effectiveness of Cr(NO₃)₃ metal salt provides milder hydrolysis conditions for highly selective depolymerization of cellulosic fiber into value-added cellulose nanomaterial, or useful chemicals and fuels in the future.
本研究报道了硝酸铬（Cr(NO₃)₃）水解从天然纤维素原料中分离纤维素纳米晶体（CNC）的可行性和实用性。将CNC的物理化学性质与使用硫酸水解法分离得到的纳米纤维素（CNC）进行了比较。在最佳水解条件下，即80℃、1.5小时、0.8M硝酸铬金属盐和固液比为1:30时，CNC呈现出网络状长纤维结构，长径比为15.7，而CNC呈现出米粒状结构，长径比为3.5。此外，与硫酸处理的CNC（分别为81.4%±0.1%和54.7%±0.3%）相比，硝酸铬处理的CNC具有更高的结晶度（86.5%±0.3%）和高收率（83.6%±0.6%）。此外，与CNC（273℃）相比，CNC（344℃）具有更好的热稳定性，这使其在纳米复合材料应用方面具有很大潜力。硝酸铬金属盐的这种相当的有效性为纤维素纤维高度选择性解聚为增值纤维素纳米材料或未来有用的化学品和燃料提供了更温和的水解条件。
