Preparation and characterization of silica nanoparticulate–polyacrylonitrile composite andporous nanofibers

Abstract

In this study, polyacrylonitrile (PAN) composite nanofibers containing different amounts ofsilica nanoparticulates have been obtained via electrospinning. The surface morphology,thermal properties and crystal structure of PAN/silica nanofibers are characterized usingattenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy,wide-angle x-ray diffraction (WAXD), scanning electron microscopy (SEM), transmissionelectron microscopy (TEM), and differential scanning calorimetry (DSC). The resultsindicate that the addition of silica nanoparticulates affects the structure and properties ofthe nanofibers. In addition to PAN/silica composite nanofibers, porous PAN nanofibershave been prepared by selective removal of the silica component from PAN/silica compositenanofibers using hydrofluoric (HF) acid. ATR-FTIR and thermal gravimetric analysis(TGA) experiments validate the removal of silica nanoparticulates by HF acid, whereasSEM and TEM results reveal that the porous nanofibers obtained from composite fiberswith higher silica contents exhibited more nonuniform surface morphology. TheBrunauer–Emmett–Teller (BET) surface area of porous PAN nanofibers made fromPAN/silica (5 wt%) composite precursors is higher than that of pure nonporous PANnanofibers.