Encapsulation of montmorillonite through RAFT controlled radical polymerization in emulsion for the production of nanostructured films with anisotropic properties

Abstract

In recent years, the incorporation of inorganic nanoparticles in a polymer matrix to produce hybrid materials with enhanced properties has received great attention from both academia and industry. Preserve and control the physicochemical properties of these nanoparticles are essential to maintain their integrity in nanoscale and ensure their uniform dispersion in the organic matrix so the properties can be enhanced. However, in order to optimize the property enhancement, it is also necessary to control their arrangement and organization in the final nanocomposite material. Among the various strategies for the synthesis of this type of material, emulsion polymerization, when compared to other methods, offers some advantages. It is environmentally friendly because it is carried out in aqueous media, and can be scaled-up for the production of latex which can be used in various segments such as coatings and adhesives. However, this technique faces limitations if the goal is the encapsulation of inorganic materials, an issue that becomes a challenge when anisotropic nanoparticles such as lamellar silicates are used as fillers. In order to overcome these limitations and to elucidate this process, this research project focuses on the production of polymer/silicate nanocomposites by controlled radical emulsion polymerization via reversible addition-fragmentation chain transfer (RAFT). Although this method has been little explored for the production of nanocomposites in aqueous medium, it offers the possibility of promoting individual encapsulation of inorganic particles by controlled growth of polymer chains on its surface. In this project, the polymerization reactions will be conducted in the presence of Montmorillonite (MMT) and RAFT macro-agents who, in addition to mediating the polymerization, will stabilize the latex particles. The latex produced will be cast and the nanocomposite films should have anisotropic properties due to the organization of the inorganic material in the polymer matrix. (AU)