2.2. Chemical modification of the CNFsThe CNFs were acetylated using the method reported by Jonoobi,Harun, Mathew, Hussein et al. (2010) briefly as follows. Prior toacetylation, the aqueous suspension containing CNFs was extractedwith acetone and methanol (2:1 by volume) in a Soxhlet for 6 h.Then, the solvent exchanged from methanol to glacial acetic acidby centrifugation (three times). The extracted CNFs, acetylated in