The Structural Evolution of Composite Latex Particles During Starve-Fed Emulsion Polymerization: Modeling and Experiments for Kinetically Frozen Morphologies

摘要

The evolution of morphology in composite latex particles is modeled under the assumption that no phase separation is allowed, resulting in fully mixed polymers in the latex particles. Such kinetically frozen, non-equilibrium structures are easily produced when the second stage polymer is glassy at reaction temperature. For a poly[-styrene-co-(butyl acrylate)] seed latex and a methyl methacrylate second-stage monomer, we show the evolution of the particle structure during the polymerization process as evidenced by TEM, DSC, and surfactant titration data. Com-rnparing these data to the model provides a mechanistic understanding of the time evolution of the particle morphology, even when a thin shell of second stage polymer is formed around a mixed core late in the reaction.