Cinkarna (Slovenia)

Titanium dioxide (TiO2) has found widespread use. Typically it is used in another matrix to impart certain properties. For example, it is widely used as a white pigment for paints and polymers. The aim of this research work was to achieve improvements in the sense of processability as well as the dispersion performance of alumina surface treated pigmentary TiO2in polymer matrix. Wet chemical method was used to modify the surface of the TiO2 pigment. Surface treatment included precipitation of hydrous oxides of aluminium on the surface of TiO2 particles. During controlled surface treatment, agglomeration has been avoided, which has been proved to improve applicative properties of TiO2 particles. In addition to that, organic additives were applied to enhance performance attributes of the pigmentary TiO2. The effectiveness of surface treatment was determined using scanning-transmission (STEM) and transmission (TEM) electron microscopy. Quantitative evaluation of quality and dispersion of the pigments has been performed using Filter pressure test. Lower pressure generated during filter pressure test when particles were well dispersed in a polymer matrix. Surface treatment also affected pigment processibility; i.e. filterability and settling, which is of high importance for process planning.

Industrial processes are most often limited in the means of production conditions, e.g., chemical agents’ selection and consumption, and time and energy conditions. In the present work, we succeeded in synthesizing a homogeneous silica layer on titanium dioxide (TiO2) core using moderate time and temperature conditions. The structure of the surface coated pigmentary TiO2 was characterized by scanning electron microscopy, transmission electron microscopy, and EDS. In our research isoelectric point (IEP) of TiO2 was determined, which occurred when the solution pH was ~4. In the meantime, the precipitation of SiO2 on TiO2 surface resulted in the shift of IEP. In addition, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller analysis were applied in order to determine differences in surface microstructure. Coating parameters were optimized to attain desired morphology of precipitated Si-hydroxide, which in turn provides improvements in one or more important performance properties such as hiding power efficiency, which was determined by the means of UV–Vis light transmittance.