Enhanced Hydrophobicity of Nanofibrillated Cellulose Through Surface Modification Using Cetyltrimethylammonium Chloride Derived from Palmityl Alcohol

Abstract: This study aims to provide an approach for increasing the hydrophobicity of nanofibrillated cellulose in oil palm empty fruit bunches (NFC-OPEFBs) through surface modification using a sustainable cationic surfactant, i.e., cetyltrimethylammonium chloride derived from palmityl alcohol (CTAC-PA). The NFC-OPEFB was prepared by sulfuric acid treatment. The hydrophobicity of NFC-OPEFB was increased following modification using CTAC-PA, indicated by an increase in the water contact angle value. The dispersibility of the modified NFC-OPEFB (modNFC) in chloroform solution was more stable than that of unmodified NFC-OPEFB (unmodNFC) as observed via ultraviolet–visible spectrophotometry and based on visual appearance. Observation through transmission electron microscopy confirmed that modNFC was completely dispersed in chloroform but undispersed in water. Furthermore, Fourier-transform infrared (FTIR) spectroscopy analysis revealed that the functional groups of NFC-OPEFB were successfully modified using CTAC-PA, justifying the increase in their hydrophobicity characteristics. Peaks were observed at 2892 and 2921 cm⁻¹ for symmetrical and asymmetrical CH₂ from the long alkyl chain of CTAC, at 1480 cm⁻¹ for the trimethyl groups of the quaternary ammonium, and at approximately 805 cm⁻¹ for the C–Cl bond on the FTIR spectra of modNFC which were absent from the FTIR spectra of the unmodNFC. This work provides an eco-friendly way to enhance the hydrophobicity characteristics of NFC-OPEFB and expand the use of NFC-OPEFB in hydrophobic polymer matrices, such as poly (lactic acid), polyethylene, etc. Graphic Abstract: [Figure not available: see fulltext.]