LAUSR

In this study, the modification of TEMPO-mediated oxidized cellulose nanofibrils (TOCNFs) with cetyltrimethylammonium bromide (CTAB) was investigated to increase the hydrophobicity, improve the fibril separation from the hydrogel, and enhance the redispersibility of the separated nanofibrils. The results showed that when modifying the original TOCNFs at a CTAB loading of 2.16 mmol/g cellulose, the charge coupling was close to 100%. Moreover, with increasing the CTAB dosage, the turbidity of the modified CTAB–TOCNFs was significantly increased while the viscosity and water retention value were decreased. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy demonstrated that the molecular chain of CTAB was successfully grafted onto the backbone of TOCNFs following modification. The thermogravimetric analysis results also indicated the modification of TOCNFs with CTAB improved its thermal stability. Water contact angle measurements of the original and CTAB modified TOCNFs showed that the modified CTAB–TOCNFs had better hydrophobicity. Moreover, the results from the evaluation of the redispersibility of the fibrils separated from both the original CNF and CTAB–TOCNF suspensions demonstrated that the modification of TOCNFs with CTAB improved the redespersibility in N,N-dimethylformamide (DMF). Additionally, the increase of CTAB loading also significantly decreased the particle size of the redispersed fibrils in DMF.