Synthesis of Transparent ZnO-TiO2 and Its Nanocomposites for Ultraviolet Protection of a Polyethylene Terephthalate (PET) Film

The goal of this research was to investigate the effects of ZnO-TiO2 and its nanocomposites, on the physical, mechanical, and ultraviolet protection of polyethylene terephthalate (PET). Exposure to ultraviolet (UV) rays is a major cause of the degradation of the quality and optical properties of materials in addition to skin cancer; therefore, research on UV-blocking materials that are safe and have fewer side effects than currently available products is being actively conducted. In this study, a material with UV-blocking capability was synthesized while ensuring the transparency of ZnO and TiO2. ZnO-TiO2 and its various composites were successfully synthesized via a hydrothermal method followed by ball milling and their properties were systematically analyzed by using scanning electron microscopy, X-ray diffractometry, Fourier-transform infrared spectroscopy, and water contact angle measurements. Furthermore, a simple dip-coating method was employed to prepare transparent polyethylene terephthalate (PET) films coated with the composites, which were subsequently investigated for UV-blocking properties by exposing them to UV irradiation. The hydroxyl groups of ZnO and TiO2, as representative inorganic sunblock components, were removed by using 3-chloropropyl trimethoxy silane as a coupling agent to improve their wettability in an organic solvent as well as their dispersibility and stability. The addition of a small amount of Tinuvin (R) allowed the hybrid organic and inorganic components to exhibit transparent UV-blocking characteristics, with a UV transmittance of <= 20% and 90% visible transmittance. These results, thus, serve as a basis for contributing to applications in the field of packaging, health, and hygiene industries.