Physicochemical, spectroscopic and thermal properties of powdered cellulose and microcrystalline cellulose derived from groundnut shells

Abstract

?-Cellulose and microcrystalline cellulose powders with desired physicochemical properties for use in the pharmaceutical industry can be derived from agricultural residues. ?Cellulose (GCN) was extracted from an agricultural residue (groundnut shell) using a non-dissolving method based on inorganic substances. Modification of this ? -cellulose was carried out by its partial hydrolysis with 2N hydrochloric acid under reflux to obtain microcrystalline cellulose (MCGN). The physicochemical, spectroscopic and thermal properties of the derived ?-cellulose and microcrystalline cellulose powders were compared with Avicel PH 101, a commercial brand of microcrystalline cellulose (MCCA), using standard methods. X-ray diffraction and infrared spectroscopy results showed that the ?-cellulose had lower crystallinity, and proved that treatment with 2N hydrochloric acid led to increase in crystalline index. Thermogravimetric analysis and differential scanning calorimetry data showed quite similar thermal behaviour for all cellulose samples, although with somewhat lower stability for the ?-cellulose. Comparison of physicochemical properties of the microcrystalline celluloses and the ?-cellulose mainly suggest that microcrystalline cellulose might have better flow and compression properties. For almost all of the characterizations carried out, it was generally observed that the microcrystalline cellulose obtained from groundnut shells had similar characteristics to the commercial brand of microcrystalline cellulose, evidencing that it can be a good low-cost alternative to the expensive commercial brand.