The optical properties and sunscreen application of spherical h-BN-TiO ₂/mica composite powder

In the present study, TiO₂/mica and hexagonal boron nitride powders were used as the starting materials to prepare composite powders by mechanical mixing and spray drying. The starting powders, as-prepared powders, and nano-TiO₂ were examined by scanning electron microscopy, particle-size analysis, and X-ray diffraction to reveal the powder morphology, particle size distribution, and crystalline phases. These powders were added to linseed oil to prepare emulsions for sunscreen applications. The powder-added emulsions were examined by UV-visible spectroscopy and a sun protection factor tester. The experimental results showed that the emulsion with spray-dried powder exhibited a significant improvement in sunscreen protection performance and was superior to its nano-TiO₂ counterpart.