Physicochemical Characterization of Cellulose and Microcrystalline Cellulose from Cordia africana Lam. Seeds

Abstract

ABSTRACT This study aims to explore Cordia africana seeds as an alternative source of cellulose and MCC due to depletion of the major commercial sources such as wood pulp, and cotton. Cellulose was extracted from Cordia africana seeds employing a chlorine-free treatment approach, followed by partial depolymerization using acid hydrolysis to obtain microcrystalline cellulose (MCC). The untreated seeds, as-extracted cellulose, and MCC were investigated for yield, chemical composition, functionality, crystallinity, morphology, diameter, and thermal stability. The cellulose content increased from 30% (w/w) in the untreated seeds to 80.2% (w/w) in cellulose and 88.1% (w/w) in the MCC. The removal of non-cellulosic constituents was confirmed by the results obtained from Fourier-transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy, and Thermogravimetric analysis (TGA)/Derivative thermogravimetry (DTG). The crystallinity index of as-obtained cellulose and MCC increased from 32.38% (untreated seeds) to 68.28 (cellulose) and 73.19% (MCC) with chemical treatments. The extracted samples exhibited characteristic peaks of Cellulose I at around 15°, 16°, 22°, and 34°. Th e TGA/DTG results confirmed the cellulose and MCC had higher thermal stability than the untreated seeds. This study shows that cellulose and MCC can be obtained from unexploited source, Cordia africana seeds, for promising applications in various industries.