Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
597145 | Colloids and Surfaces A: Physicochemical and Engineering Aspects | 2008 | 10 Pages |
Abstract
Mixed Ta2O5/SiO2 nanoparticles are attractive for their high radiopacity as transparent dental fillers and even for bone replacement. The effect of Ta2O5 content on surface acidity of flame-made Ta2O5/SiO2 particles was studied by NH3 temperature-programmed desorption (TPD). Emphasis was placed on the influence of particle composition on surface functionalization by a common surfactant, γ-methacryloxypropyltrimethoxysilane (MPS). Such surface modified particles were analyzed by thermogravimetric analysis, 13C- and 29Si-NMR and FT-IR spectroscopy. Compared to pure silica, Ta2O5/SiO2 particles exhibited significantly higher surface acidity, thereby facilitating functionalization of their surface hydroxyl groups without a catalyst (e.g. n-propylamine, PA). The surface modifier structure was only slightly influenced by the Ta2O5 presence compared to pure SiO2. The long term hydrolytic stability of such surface modified Ta2O5/SiO2 particles was comparable to pure silica up to 80 days at 22 °C indicating stable bonding between particle surface and modifier.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Colloid and Surface Chemistry
Authors
Heiko Schulz, Sotiris E. Pratsinis, Heinz Rüegger, Jörg Zimmermann, Simone Klapdohr, Ulrich Salz,