Synthesis of organo-attapulgite/polyacrylate nanocomposite latex by soap-free emulsion polymerization and its enhanced film properties

Clay-polymer nanocomposites have attracted extensive attention because of their improved properties. It is particularly desirable to explore the effects of different clays on the preparation and performances of their nanocomposites. In this paper, a rod-shaped organo-attapulgite (OATP) was used to prepare the clay-polymer nanocomposites by emulsion polymerization of methyl 2-methacrylate, n-butyl acrylate and hydroxypropyl acrylate. It was found that OATP had a unique influence on the emulsion polymerization, the polyacrylate structure and the performances of composite latex and its film. For the emulsion polymerization, the conversion of monomers decreased and the coagulum rate increased with increasing OATP from 0.1 to 0.9 mass%. However, the molecular weight of polyacrylate increased significantly, and the ratio of monomers in the polymer was gradually close to the feeding ratio. Furthermore, the addition of OATP led to long and large-sized latex particles, as well as a decrease in the viscosity and chemical stability of latex, but the thermal stability, pencil hardness and adhesion of latex films were improved. For optimal performance, a suitable amount of OATP addition was 0.6 mass%. In summary, OATP/polyacrylate nanocomposite latex has potential application prospects as a new composite coating material.