AbstractRegenerated cellulose (RC) biocomposite films from oil palm empty fruit bunch (OPEFB) and microcrystalline cellulose (MCC) were prepared using ionic liquid. N,N-Dimethylacetamide (DMAc) and Lithium Chloride (LiCl) were used to dissolve the regenerated cellulose at room temperature. The effects of OPEFB content and chemical modification using methacrylic acid (MAA) on the X-ray diffraction, tensile properties, morphology, thermal properties, and Fourier transform infrared spectroscopy (FTIR) results for RC biocomposite films were investigated. The chemical modification of OPEFB using MAA enhanced the properties of the treated RC biocomposite films. At 2 wt.% of OPEFB both of the RC biocomposite films showed the highest crystallinity index, tensile strength, modulus of elasticity, and thermal stability. The treated RC biocomposite films had a higher crystallinity index, tensile strength, modulus of elasticity, and thermal properties than the untreated RC biocomposite films. The Tdmax of treated RC biocomposite films with MAA was higher than that of untreated RC biocomposite films. This indicates that treated biocomposite films had higher thermal stability. The enhancement of interfacial interaction and the dispersion of treated RC biocomposite films with MAA were revealed by scanning electron microscopy (SEM). The FTIR spectra of treated RC biocomposite films indicated interaction between cellulose from OPEFB and MCC with MAA.