Polymer–Clay Nanocomposites by Miniemulsion Polymerization
To prepare PCN by means of in-situ miniemulsion polymerization is not an easy task, since clay can interact with all components in the system (monomer, surfactant, hydrophobe) influencing thus the droplet size distribution after miniemulsification step as well as the polymerization loci. As a result the mechanisms of miniemulsion polymerization in the presence of the clay are not fully understood and stable latexes with reasonable solids content are difficult to achieve. The ideal case of miniemulsions stabilized by surfactants is, when the organoclay platelets are encapsulated inside the polymer particles. Despite that the clear evidence of fully encapsulated clay platelets inside the polymer particles was not achieved up to now, the idea of clay inside the droplets/particles not influencing the stability, providing high solids content with low surfactant loading (high amounts of surfactant might impart deleterious properties to the films cast from the latexes) and generally not bringing another complexity to already complex miniemulsion polymerization, is very attractive.