Properties of microcrystalline cellulose extracted from soybean hulls by reactive extrusion

•Microcrystalline cellulose was obtained from soybean hulls by reactive extrusion.•Extrusion process was carried out in two steps, first with NaOH, followed by H2SO4.•Reactive extrusion was effective in obtaining MCC with less effluent production.•MCC from soybean hulls were 83.79% cellulose and 70% crystallinity.

The objectives of this study were to produce microcrystalline cellulose (MCC) from soybean hulls (SH) employing a simple method based on reactive extrusion, and to characterize the product according its microstructure, morphology, crystallinity and thermal stability. MCC was obtained from SH after a two-step extrusion process; in the first step, the SH was extruded with sodium hydroxide (NaOH), followed by extrusion with sulfuric acid (H2SO4) in the second step. The MCC produced from SH by reactive extrusion was composed of short and rod shaped fibers, with a cellulose content of 83.79% and a crystallinity index of 70%. Reactive extrusion is an alternative and effective method for the production of MCC from lignocellulosic residues, and has the advantages of simplicity and was less polluting than conventional methods.