Transparent Zirconia Research Articles

Transparent zirconia gel-monolith from zirconium alkoxide

Transparent zirconia gel-monoliths were prepared by controlled hydrolysis of stabilized zirconium alkoxide. The gel after drying at 60°C was amorphous to electron diffraction. Infrared spectroscopic study indicated that the molecular structure of the dried gel was different from that of the precipitated zirconia as reported in the literature. The pore-structure of the dried gel when examined from its N 2-desorption isotherm and the pore size distribution curve obtained by the BJH method indicated that the gel was microporous with most of the pore sizes less than ∼ 15 A ̊ in radius.

Platinum: The most precious of the metals

The precursor zirconium oxychloride octahydrate (ZrOCl2·8H2O) was firstly used to prepare clear and transparent zirconia sol via an auto-hydrolysis sol-gel method without the water. Triethylamine (TEA) and dimethylaminoethyl methacrylate (DMAM) were used as acid binding agents to control the pH value in the sol-gel process. Silane coupling agent, acetylacetone (acac) and isopropyl tri(dioctyl)pyrophosphato titanate (titanate coupling agent, NDZ-201) were utilized to protect the zirconia nanoparticles and improve the interaction between the organic network and inorganic component in UV-curing hybrid coatings. The hydrolysis and condensation processes were monitored by FT-IR. The particle size and distribution of zirconia sol with different coupling agents were evaluated by the transmission electron microscopy (TEM). The Scanning electron microscopy (SEM) indicated that the particle size was smaller and had a more uniformity dispersion when NDZ-201 was used. An organic/inorganic interpenetrating network (IPN), which was based on polyacrylate and zirconia nanoparticles, was probably formed by the proper ratio of acrylates to zirconia sol during the UV-curing process. Thermal Mechanical Analysis (TMA) results showed that the IPN structure had a higher Tg. Notably, the hardness and flexibility of the UV-curing hybrid coatings were simultaneously improved compared with the UV-curing pure organic polymer.