Tailored production of lignin-containing cellulose nanofibrils from sugarcane bagasse pretreated by acid-catalyzed alcohol solutions

In this study, sugarcane bagasse was pretreated with acid-catalyzed alcohols, i.e., ethanol (AE), ethylene glycol (AEG) and glycerol (AG) to prepare pulps for producing lignin-containing cellulose nanofibrils (LCNF) with tailored properties, such as hydrophilicity/hydrophobicity and dispersion stability. The results showed that AG-LCNF had the highest lignin content of 16% but relatively low hydrophobicity while AE-LCNF had a low lignin content of 11% but the highest hydrophobicity. LCNF diameter distribution, crystallinity, zeta potentials and thermal stability were also determined to understand the effects of pretreatment solvent. NMR analyses revealed that alcohols modified lignin at α-position by etherification and γ-position by esterification of aliphatic chains, subsequently affecting lignin oxidation by TEMPO in the LCNF production processes, LCNF properties and LCNF dispersion in different solvents. This study provided fundamental information in the design and tailored production of LCNF for various applications, such as manufacturing polymer composites and Pickering emulsions.