Transparent and Flexible Cellulose Triacetate–TiO₂ Nanoparticles with Conductive and UV-Shielding Properties

Cellulose triacetate (CTA) and sol–gel synthesized TiO₂ nanoparticles were used to develop and characterize novel nanocomposites modified also with poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (EPE) triblock copolymer. The designed nanocomposites presented UV-shielding properties, being the protection higher at high sol–gel content, with suitable surface finish and high transparency even with 20 vol % sol–gel content. The DSC results showed a decrease of the Tg and Tₘ of the CTA phase, indicating a partial miscibility between the nanocomposite components. The AFM measurement indicated that the addition of EPE triblock copolymer led to the nanostructuration of the CTA matrix, allowing to control the dispersion of the TiO₂ nanoparticles since the PEO block acted as surfactant for the TiO₂ nanoparticles preventing their aggregation. The EFM measurement proved that the TiO₂ nanoparticles embedded in the CTA or the PEO block/CTA matrix maintained their conductive properties. Moreover, the TiO₂ nanoparticles acted as reinforcement improving the Young’s modulus of nanocomposites. The designed nanocomposites presented interesting properties and surface appearance to design a wide variety of products.