Preparation of ion‐containing elastomers by emulsion copolymerization of dienes with olefinic sulfonic acid salts

Procedures were developed for the emulsion copolymerization of either butadiene or isoprene with several different water‐soluble monomers containing sulfonic acid salt groups, primarily with sodium styrenesulfonate, for the preparation of ionomer elastomers. By the use of a nonionic surfactant and a two‐component redox initiator, which was based on a water‐soluble reducing agent and a hydrophobic peroxide, copolymers with sufficient amounts of the ionic monomer could be prepared. Unusual effects of conversion on rate, copolymer composition, and molecular weight were observed and attributed to special effects caused by the ionic monomers. The copolymers were soluble in mixed hydrocarbon–alcohol solvent systems.