Preparation and characterization of magnetic cellulose fibers modified with cobalt ferrite nanoparticles

Magnetic fibers were prepared by lumen loading method using bleached eucalyptus fibers as cellulose source and cobalt ferrite nanoparticles (CoFe₂O₄). For this, CoFe₂O₄ nanoparticles were first synthesized by the chemical co-precipitation method and then incorporated into eucalyptus fibers using polyethylenimine (PEI) as retention-aid. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM-EDS), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) for magnetic properties. The obtained nanoparticles showed an inverse cubic spinel crystalline structure with an average size of 9 nm, exhibiting further a ferrimagnetic behavior. It was observed in the SEM images the deposition of nanoparticles on surface and into macropores of fibers. The results indicate a maximum saturation magnetization of ∼8 emu/g for the modified fibers. Besides, through an experimental design, it was established that loading degree and magnetic response of modified fibers are affected by both dose of nanoparticles and agitation time used in the modification process.