Department of Bioproducts and Biosystems, Aalto University, FI-00076 Aalto, Finland.
Department of Chemistry, University of Helsinki, PB 55, FI-00014 Helsinki, Finland.
Biomacromolecules. 2023 Mar 13;24(3):1318-1328. doi: 10.1021/acs.biomac.2c01363. Epub 2023 Feb 7.
Phosphorylation of cellulose nanocrystals (CNCs) has remained a marginal activity despite the undisputed application potential in flame-retardant materials, sustainable high-capacity ion-exchange materials, or substrates for biomineralization among others. This is largely due to strenuous extraction methods prone to a combination of poor reproducibility, low degrees of substitution, disappointing yields, and impractical reaction sequences. Here, we demonstrate an improved methodology relying on the modification routines for phosphorylated cellulose nanofibers and hydrolysis by gaseous HCl to isolate CNCs. This allows us to overcome the aforementioned shortcomings and to reliably and reproducibly extract phosphorylated CNCs with exceptionally high surface charge (∼2000 mmol/kg) in a straightforward routine that minimizes water consumption and maximizes yields. The CNCs were characterized by NMR, ζpotential, conductometric titration, thermogravimetry, elemental analysis, wide-angle X-ray scattering, transmission electron microscopy, and atomic force microscopy.
尽管纤维素纳米晶体（CNC）在阻燃材料、可持续高容量离子交换材料或生物矿化基质等方面具有无可争议的应用潜力，但对其进行磷酸化处理的应用仍十分有限。这主要是由于其提取方法费力，容易出现重现性差、取代度低、产率不佳和反应序列不切实际等问题。在这里，我们展示了一种改进的方法，该方法依赖于磷酸化纤维素纳米纤维的修饰程序以及通过气态 HCl 进行水解来分离 CNC。这使我们能够克服上述缺点，并以一种简单的方式可靠且可重复地提取具有极高表面电荷（约 2000mmol/kg）的磷酸化 CNC，该方法最大限度地减少了水的消耗并提高了产率。通过 NMR、ζ 电位、电导率滴定、热重分析、元素分析、广角 X 射线散射、透射电子显微镜和原子力显微镜对 CNC 进行了表征。
