Effect of the Delignification Process on the Physicochemical Properties and Thermal Stability of Microcrystalline Cellulose Extracted from Date Palm Fronds

Abstract

In this study, pure cellulose was isolated from Algerian date palm fronds (DPF) using three different delignification processes (acidified NaClO2, totally chlorine free (TCF) and their combination). Then, microcrystalline cellulose (MCCs) particles have been successfully produced via direct acid hydrolysis of the different celluloses. All samples were characterized using infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TGA) and differential scanning calorimeter (DSC). From the FTIR analysis, most of hemicellulose and lignin were effectively removed throughout the extraction processes. The XRD spectra revealed that all MCCs belong to cellulose I type, and showed a highly crystallinity index than that of pure celluloses. According to DSC and TGA/DTG analyses, the MCC samples presented a higher decomposition temperature. The obtained results showed that the extracted MCC samples exhibited similar properties than those of commercial MCC. Furthermore, the employment of a combined process allowed obtaining MCC with higher crystallinity and better thermal stability. Thus, according to these results, date palm fronds can be considered as a potential low-cost material for MCC production and the combined process is promising to isolate high purity MCC from cellulosic substrate.