AbstractCellulose nanofibers were isolated from kenaf core fibers by employing chemo-mechanical treatments. The morphologies and sizes of the fibers were explored with environmental scanning electron microscopy (ESEM) and transmission electron microscopy (TEM). The results of chemical analysis showed that the cellulose contents of the bleached pulp fibers and nanofibers increased from 46% to 92% and to 94%, respectively. Most of the produced nanofibers had diameters in the range of 20 to 25 nm, whereas kenaf nanofibers ranged in diameter diameters from 10 to 75 nm. Fourier transform infrared spectroscopy (FTIR) analysis revealed the removal of lignin and the majority of the hemicelluloses from the kenaf core fibers. The thermogravimetric analysis (TGA), which was carried out to evaluate the thermal properties of the fibers, demonstrated that the thermal stabilities of these fibers were increased by the chemo-mechanical treatments. The results of X-ray analysis confirmed that chemical and mechanical treatments can improve the crystallinity of fibers.