Using ultrasound-assisted dispersion and in situ emulsion polymerization to synthesize TiO₂/ASA (acrylonitrile-styrene-acrylate) nanocomposites

In this study, TiO₂/acrylonitrile-styrene-acrylate (ASA) nanocomposites with different loading content of TiO₂ were prepared via in situ emulsion polymerization. Before the polymerization, TiO₂ nanoparticles were dispersed in the reaction monomer by ultrasonic to reduce the agglomeration of TiO₂. A series of characterization were taken to study the properties of the nanocomposites. The result of Wide angle X-ray diffraction (WAXD) analysis indicated that the crystal form of TiO₂ remained unchanged after the in situ emulsion polymerization. Interestingly, the introduction of TiO₂ induced a significant improvement in the impact toughness of TiO₂/ASA nanocomposites, which increased dramatically by about 10 kJ/m² compared with neat ASA. And we attributed this improvement to the better dispersibility of TiO₂ in ASA matrix which is proved by Transmission Electron Microscopy (TEM) analysis. In addition, the solar reflectance of the nanocomposites was related to the addition of TiO₂ nanoparticles. The more the TiO₂ nanoparticle was added, the higher the solar reflectance of the nanocomposite was. Moreover, the outdoor temperature test just proved the result of the solar reflectance.