Tianjin Key Laboratory of Pulp and Paper, Tianjin University of Science and Technology, Tianjin 300457, China.
Department of Chemical Engineering, Auburn University, Auburn, AL 36849, USA.
Carbohydr Polym. 2021 Aug 15;266:118107. doi: 10.1016/j.carbpol.2021.118107. Epub 2021 Apr 24.
In this work, a sustainable and highly efficient approach for preparing bifunctional cellulose nanocrystals (CNCs) was proposed through a mixed acid system of sulfuric acid and formic acid (FA). It was found that low-concentration (5-10 wt%) sulfuric acid can significantly improve the hydrolysis efficiency of FA (65-80 wt%), which enabled the highly efficient preparation of CNCs, i.e., the maximum yield of CNCs reached up to 70.65%. The obtained CNCs exhibited a rod-like shape with high crystallinity, and good dispersibility in both water and some organic phases. Moreover, the as-prepared CNCs exhibited high thermal stability, which is much higher than that of the traditionally sulfuric acid hydrolyzed ones. In addition, it was demonstrated that the bifunctional CNCs were able to stabilize various oils to form stable Pickering emulsion gels. Thus, this work provides a promising approach for sustainable preparation of bifunctional CNCs, which may find high-end applications in diverse fields.
在这项工作中，通过硫酸和甲酸（FA）的混合酸体系，提出了一种可持续且高效的制备双功能纤维素纳米晶体（CNC）的方法。研究发现，低浓度（5-10wt%）的硫酸可以显著提高 FA（65-80wt%）的水解效率，从而实现 CNC 的高效制备，即 CNC 的最大产率可达 70.65%。所得 CNC 呈棒状，具有高结晶度和在水和一些有机溶剂中良好的分散性。此外，所制备的 CNC 表现出高热稳定性，远高于传统硫酸水解的 CNC。此外，还证明了双功能 CNC 能够稳定各种油，形成稳定的 Pickering 乳液凝胶。因此，这项工作为可持续制备双功能 CNC 提供了一种有前景的方法，它可能在各个领域找到高端应用。
