Synthesis of TiO2 core-shell/Nanocomposite containing hydrophobic polymers

Titanium oxide is a very important and interesting material because of its photo-catalytic activities. TiO2 fillers are used in paint and enamel as white pigment with the aim to improve mechanical properties. Due to its photo-catalytic properties titanium oxide is also used for air cleaning devices (to remove pollutants as NOX), in the production of self-cleaning surfaces or stain-resistant fabrics, for antimicrobial and antifungal coatings, in UV protection materials and in the solar energy conversion. Many studies had reported that nanofiller particles are better than traditional fillers because they give same or better performances using less material. Specifically for TiO2, nanodimension enhance optical and catalytic properties. The main drawback is the aggregation of hydrophilic nanoparticles when used into hydrophobic polymer matrix. A good method to ensure the formation of a dispersion is the grafting of a polymer around the particle. In this study vinyltriethoxysilane (VTEOS) and 3-(trimethoxysilyl)propyl methacrylate (MPS) have been used as coupling agents in order to functionalize the TiO2 with a reactive double bond and subsequently these functionalized nanoparticles have been used to obtain core-shell nanocomposites by radical polymerization with vinylacetate, butyl acrylate, methyl methacrylate and/or a mixture of them. Copolymers of VTEOS or MPS with the above monomers have also been synthesized and characterized with the aim to observe the different behaviour respect to TiO2 nanocomposites. Selective extractions in organic solvents have been used in order to separate different components of the nanocomposites and the fractions obtained have been characterized by NMR and FT-IR spectroscopy and TEM microscopy.