Bimodal high solids content latices using RAFT‐mediated polymerization‐induced self‐assembly and semi‐batch emulsion polymerization

Abstract This work focuses on increasing the solids content of water‐based coating materials such as paints, other coatings or adhesives while attempting to reduce the amount of surfactant in the final latex. The synthesis of a latex with a bimodal particle size distribution was carried out by combining RAFT and classical emulsion polymerization processes. By employing the RAFT polymerization, the population of small particles was created by self‐ordering the block copolymer chains, consisting of a hydrophilic block based on methacrylic acid or sodium 4‐styrenesulfonate and another hydrophobic block based on styrene. The final latex was made by adding a pre‐emulsion prepared from the latex of small particles and a mixture of monomers and surfactants to the latex of large particles made via conventional emulsion polymerization. The final bimodal latex thus obtained had a solids content of 65% mass with a viscosity value of around 2.0 Pa.s at a shear rate of 20 s −1 .