Nanofibrillated cellulose surface grafting in ionic liquid
The present study reports for the first time the heterogeneous surface modification of nanofibrillated cellulose (NFC) in ionic liquid using different anhydride molecules. With ecofriendly perspectives in mind, the ionic liquid used was recycled by liquid–liquid extraction. The purity of the recycled IL was confirmed by FTIR measurements and NMR spectra of 1H, 13C, 31P and 19F. All the NFC samples were characterized by different techniques (e.g. FTIR, contact angle measurements) to check the efficiency of grafting and to compare the influence of the different anhydrides used. The surface chemical grafting obtained was effective. The Degree of Substitution (DS) was determined by elemental analysis and the Degree of Surface Substitution (DSS) was calculated from X-ray photoelectron spectroscopy data. ToF-SIMS was used to characterize the grafting at the extreme surface.