Surface Modifications on the Structure and Properties of Acid-Activated Sepiolite Nanofibers

In recent years, continuous advancements in nanotechnology have driven the widespread application of natural mineral materials across various fields. To further enhance the potential application of sepiolite nanofibers as fillers in composite materials, this study commenced with acid-activated sepiolite nanofibers, focusing on the modification and optimization of the surface of acid-activated bentonite nanofibers. Successfully prepared were methyl trimethoxysilane-modified bentonite nanofibers (MTMS/A-SEP), hexadecyltrimethylammonium bromide-modified bentonite nanofibers (CTAB/A-SEP), as well as PEG-800/A-SEP and PEG-4000/A-SEP. Through analysis of the results from scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), the successful incorporation of the modifying agents was confirmed. Additionally, the dispersion, compatibility at the organic phase interface, and thermal stability of the surface-modified bentonite nanofibers were characterized using zeta potential, Brunauer–Emmett–Teller (BET) and thermogravimetric analysis (TGA) tests. The selected surface-modified bentonite nanofibers, which are most compatible with the organic matrix interface, demonstrated excellent dispersion and thermal stability, establishing a foundation for their subsequent application in sepiolite-based composite materials.