One-pot preparation of hydrophobic cellulose nanocrystals in an ionic liquid
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The facile one-pot preparation of hydrophobic cellulose nanocrystals (CNCs) from wood pulpboard in an ionic liquid is reported in the present paper. This process employed a so-called amorphous cellulose solvent system capable of dissolving the majority of the amorphous regions in cellulose while maintaining the crystalline domains essentially intact, and consisting of tetrabutylammonium acetate with dimethylacetamide. These solvents were mixed at a mass ratio of 1:9 in conjunction with acetic anhydride to prepare CNCs via surface acetylation. The rod-like morphology and nanometer-scale dimensions of the resulting CNCs were ascertained by atomic force microscopy and transmission electron microscopy. Successful surface acetylation while maintaining an intact crystalline core was confirmed by Fourier transform infrared, 13C CP/MAS NMR and X-ray photoelectron spectroscopy in addition to X-ray diffraction. Finally, the thermal stability and hydrophobic behavior of the hydrophobic CNCs were characterized using thermal gravimetric analysis and water contact-angle measurements, respectively.
KeywordsTetrabutylammonium acetate Hydrophobic CNC One-pot method Surface modification Amorphous cellulose solvent system
The authors wish to acknowledge the financial support of the Fundamental Research Funds for the Central Universities (No. BJYJ 201518) and the “948” Project of the State Forestry Administration (No. 2013-4-03).
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