Aqueous Dispersions of Ethylene Copolymers and Their Laponite Clay Nanocomposites from Free-Radical Dispersion Polymerization

摘要

Aqueous dispersions of ethylene copolymers with polar comonomers are of practical interest, e.g., as additives for paints or water-based adhesives. We report insights on the free-radical heterophase copolymerization of ethylene with vinyl acetate, acrylates, methacrylates, acrylamides, and ionic vinyl or (meth-)acrylate comonomers. Copolymers with polar comonomer contents of 0.1-10 mol % were obtained via a surfactant-free dispersion copolymerization at relatively mild conditions (250 atm, 85 degrees C). This allows for tuning of the low-density polyethylene particle surface properties, as demonstrated for polymer nanocomposite particles with Laponite clay in a Pickering-stabilized dispersion polymerization approach. Mechanistic insights on particle formation and stabilization are discussed.