Surface Functionalization of Kenaf Fibers With Lauroyl Chloride: Effects of Alkaline Pretreatment Method

Abstract

Surface functionalization of cellulose fibers is the current focus of research seeking to develop composite materials for various applications. One reason is the low compatibility of natural cellulose-based fibers with thermoplastic matrices for the production of wood-plastic composites. In this research, kenaf fibers (KF) were esterified with lauroyl chloride. Before the esterification reaction, two alkaline pretreatment methods were used: Bain-Marie at low temperature, and at high temperature and pressure in the digester. SEM results showed a smoother surface morphology after esterification. ATR-FTIR results confirmed the substitution of hydroxyl groups of cellulose with lauroylate functional groups. Increasing the carbon content in EDX spectroscopy further supported the successful esterification of kenaf fibers, which is in accordance with ATR-FTIR findings. Based on ATR-FTIR and EDX results, the Bain-Marie pretreatment method was more effective for the esterification reaction. According to the XRD results, the crystallinity index of the fibers slightly increased after esterification reaction. However, the fibers pretreated in the digester had a higher crystallinity index, which was related to efficient removal of amorphous regions due to higher temperature and pressure used in the digester process. This research showed that alkaline pretreatment in Bain-Marie was more effective for the surface functionalization of cellulose fibers than the digester process. These results can be applied in future research works for esterification of cellulose fibers.