AbstractThe addition of silver nitrate to polymerizable systems containing butadiene can result in increased over‐all rates of conversion. When butadiene is the only monomer and a cationic soap is used the addition of silver nitrate causes* a significant decrease in rate. The most active system studied was one which contained butadiene, styrene, a cationic soap, a peroxide, and silver nitrate. Comparison runs in a GR‐S type formulation with silver nitrate and potassium ferricyanide indicate that the silver salt is the more effective in producing higher over‐all rates of conve