Min Wu, Yong Huang, and colleagues, Chinese Academy of Sciences, Beijing, China, and Shigenori Kuga, University of Tokyo, Japan, report that native cellulose can be dispersed as nanofibers in organic solvents by ball milling with esterification agents. Ball mills are rotating cylinders which are partially filled with the material to be ground and the grinding medium. Milling with hexanoyl chloride/DMF gives hexanoyl-coated nanofibers dispersible in several organic solvents. Milling with succinic anhydride/DMSO results in water-dispersible nanofibers.
The nanometer-scale individualization was confirmed by electron microscopy, and surface esterification was evidenced by FTIR and X-ray diffraction.
The results open the way to new cellulose mechanochemistries. The technique of mechanochemical derivatization–dispersion may have a wide range of applications. Ball milling may be replaced by disk refining/grinding, sonication, or high-pressure homogenization. A very large number of solvent–reagent combinations is possible. The method may be extended to aqueous systems and also to the solubilization of cellulose derivatives.
- One-Step Dispersion of Cellulose Nanofibers by Mechanochemical Esterification in an Organic Solvent,
Pei Huang, Min Wu, Shigenori Kuga, Deqian Wang, Dayong Wu, Yong Huang,