Preparation And Characterization Of Silica Sol/Polyacrylate Nanocomposite Emulsion

In recent years, organic/inorganic composite nanoparticles are of great interest, as they are expected to have combined the properties of both components such as thermal stability, mechanical strength, electrical properties, rheological properties, magnetic properties and optical property. SiO2/polyacrylate nanocomposite systems are new classes of polymeric materials which could be applied in many fields. Organic-inorganic hybrid nanomaterials have attracted much interest because of their extensive potential applications in various fields of material science, ranging from paints, magnetic fluids, and high-quality paper coating to catalysis, microelectronics, and biotechnology.Fluoropolymers exhibit a unique combination of high mechanical and thermal stability, chemical inertness, extremely low surface energy and related unwettability. Silicon-containing polymers represent attractive surface properties coupled with an exceptionally low glass transition temperature, low elastic modulus, and high thermal and chemical stability. New polymer architectures combining in a single polymer the unique properties of both fluorinated and silicated polymers can provide interesting new materials, particularly with regard to potential for nonwetting surfaces with low surface energy.In our work, we prepared the silica sol according to the Stober method in the room temperature and following prepared the KH570modified silica sol. Then the silica sol/fluoroacrylate core-shell nanocomposite emulsion was successfully synthesized via traditional emulsion polymerization with the grafting of KH-570onto silica particles. This method avoids the cumbersome steps of synthesizing the fluorosilcone monomer and introduces chemical bond between organic and inorganic phase to improve their compatibility. The products were characterized by Fourier transform infrared (FTIR), photon correlation spectroscopy (PCS), transmission electron microscopy (TEM), and thermogravimetry (TGA), Contact angle and UV-Vis analyses techniques. In addition, the formation mechanism of core-shell structure silica sol/fluoroacrylate nanocomposite latex particles was speculated.Miniemulsion polymerization technique had been found to be a particularly attractive way to obtain nanocomposite because of the mechanism of polymerization. In our work, buytl acrylate/styrene monomers containing the well-dispersed silica particles with the size of about40nm were miniemulsified after the coupling treatment of silica with3-(trimethoxysilyl) propyl methacrylate, and were subsequently polymerized to obtain modified silica sol/poly(butyl acrylate-styrene) nanocomposite emulsion. The effect of the emulsifier content and KH570modified silical sol content on the stability was tested. And the influence of the variation of polymerization temperature, initiator concentration and emulsifier concentration on the polymerization rate was investigated and also the activation energy of the reaction was estimated. We also tested the water absorption and surface free energy of the emulsion film.