Thermal and Structural Characterization of TiO2 and TiO2/Polymer Micro Hollow Spheres

• Published in: Chemical engineering & technology Vol. 33; no. 12; pp. 2029 - 2036
• Main Authors: Sgraja, M., Blömer, J., Bertling, J., Jansens, P. J.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.12.2010; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Applied sciences; Chemical engineering; Exact sciences and technology; Hollow spheres; Microcapsules; Sintering, pelletization, granulation; Solid-solid systems; Thermal hydrolysis; Gravimetric analysis; Scanning electron microscopy; Porosimetry; Carbon dioxide; Microcapsule; pH; Agglomeration; Titanium oxide; Calcining; Vaporization
• ISSN: 0930-7516; 1521-4125
• DOI: 10.1002/ceat.201000288

Micro hollow spheres, synthesized by the coating of tetradecane filled microcapsules with titanium dioxide, are characterized using thermal gravimetry (TG), infrared spectroscopy (IR), Hg‐porosimetry and scanning electron microscopy (SEM). The investigations show a strong dependence of the coating efficiency on the initial pH (precipitation in water or dilute sulfuric acid) as well as the specific capsule surface present in solution. Since the process is dominated by heterogeneous precipitation, the coating efficiency is governed by the counteracting processes of capsule‐TiO2 and TiO2‐TiO2 agglomeration. TG‐IR analysis of the capsules shows the vaporization of tetradecane prior to the decomposition of the polymeric wall to carbon monoxide, carbon dioxide and water. After the extraction or calcination of the core microcapsules, stable inorganic and organic‐inorganic hollow spheres are obtained. Hollow spheres in the micrometer range can considerably improve the mechanical, thermal and acoustical properties of materials. Inorganic and organic‐inorganic hollow spheres, synthesized by coating of microcapsules with titanium dioxide, are characterized with regard to layer thickness and thermal, mechanical and structural properties.