Environmentally friendly wollastonite@TiO2 composite particles prepared by a mechano-chemical method
Xifeng Houa,b, Yihe Zhanga,*, Hao Dinga,*, Paul K. Chuc
Core–shell wollastonite@TiO2 (W@T) composite particles are prepared by a mechano–chemical method (MCM) to improve the dispersion of TiO2 and reduce its dosage, and to achieve synergistic effects with the wollastonite mineral. The crystal structure, morphology, functional groups, and pigment properties of the as-prepared composite powders are determined. The W@T composite particles are formed by van der Waals force in addition to electrostatic attraction and chemical bonding. The anatase TiO2 coating is anchored on the wollastonite surface by Si—O—Ti and Ca—O—Ti bonds. The W@T powders possess excellent characteristics such as whiteness of 96.6%, hiding power of 17.97 g/m2, and oil absorption of 22.72 g/100 g. The properties of the W@T composite are similar to those of TiO2 and the former, which is much cheaper, can potentially substitute the latter as a white paint in many applications.
Wollastonite; TiO2; Composite particles; Mechano-chemical method