Preparation of SiO2-PVA nanocomposite and monolithic transparent silica glass by sintering

Abstract

We present a procedure for fabricating transparent silica glass that involves the sintering of green bodies prepared from an inorganic-organic nanocomposite. The nanocomposite was prepared from fumed silica and poly(vinyl alcohol) (PVA). We investigated the SiO2-PVA nanocomposite by Fourier transform infrared spectrometry (FT-IR) measurement, transmission electron microscopy and electron energy-loss spectroscopy, and the results revealed homogeneously dispersed SiO2 nanoparticles and PVA. We examined the relationship between the pH and ζ potential of the SiO2 suspension and the formability of the SiO2-PVA nanocomposite. Formability of the SiO2-PVA nanocomposite was dependent on the pH of the SiO2 suspension, and a monolithic SiO2-PVA nanocomposite without cracks was obtained using a SiO2 suspension at around the isoelectric point (pI). By sintering the SiO2-PVA nanocomposite in air at 1100°C, monolithic transparent silica glass was obtained with no cracks. The glass is highly transparent from the ultraviolet to the visible region. © 2011 The Ceramic Society of Japan. All rights reserved.