Preparation of UV-curing polymer-ZrO2 hybrid nanocomposites via auto-hydrolysis sol-gel process using zirconium oxychloride octahydrate coordinated with organic amine

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.