A comparative study of the preparation and physical properties of polystyrene-silica mesocomposite and nanocomposite materials

In this paper, a comparative study with regard to the preparation and physical properties of as-prepared polystyrene-silica mesocomposite (PSM) and polystyrene-silica nanocomposite (PSN) materials is presented. Vinyl-modified mesoporous silica particles with a wormhole structure were first prepared by doping a sol-gel metal oxide with an optically active non-surfactant (dibenzoyl-L-tartaric acid) as a template, followed by template removal through Soxhlet extraction. The as-prepared silica particles with/without mesopores were subsequently characterized using the Brunauer-Emmett-Teller method and transmission electron microscopy (TEM) and Fourier transform infrared, C-13 NMR and Si-29 NMR solid-state spectroscopy. A specific feed amount of silica particles was subsequently reacted with styrene monomer by free radical polymerization to yield a series of PSM and corresponding PSN materials. Both as-prepared composite systems were further characterized using TEM and scanning electron microscopy/energy-dispersive X-ray mapping studies. A systematic comparative study of the physical properties of both as-prepared composite materials clearly illustrated that PSM had effectively enhanced thermal stability, optical clarity and dielectric properties compared to the corresponding PSN counterpart. Evaluation was carried out using thermogravimetric analysis, differential scanning calorimetry, UV-visible transmission spectroscopy and dielectric constant measurements. (C) 2011 Society of Chemical Industry