Starch-based biocomposite membrane reinforced by orange bagasse cellulose nanofibers extracted from ionic liquid treatment

Abstract

Agricultural crop residues are known to be a renewable source of value-added products, and their application as a bio-based production chain type in the circular bioeconomy system is considered efficient in minimizing environmental problems. Value-added products, such as cellulose nanofibers (CNFs) from lignocellulose in agriculture residues, have been widely applied in the production of membranes that have desirable physicochemical characteristics. In this work, orange bagasse residue was used to obtain cellulose nanofiber and then applied to starch membranes as a mechanical reinforcement. The 1-methylimidazolium ionic liquid was used as biomass treatment for cellulose nanofiber isolation, and then two starch membranes were prepared with 5% (v/v) of cellulose nanofiber solution at 70 °C and 90 °C by the casting method. The cellulose nanofibers and membranes were characterized by scanning electron microscopy, fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. Thickness and tensile tests were applied to the membranes. Cellulose nanofibers less than 100 nm in diameter were obtained by the 1-methylimidazolium treatment, and the characterization analyses showed that the CNFs were incorporated into the membranes, which improved their mechanical resistance and thermal degradation capacity. However, membrane 1, which was prepared at 70 °C, showed a particularly significant gain in tensile strength.