Stopping/restarting free radical polymerizations

摘要

A method for stopping and restarting the free-radical polymerization of vinyl monomers (e.g. acrylic monomers) without forming low molecular weight polymer is provided. These polymerizations utilize a Redox catalyst system comprising multivalent metal ions (e.g. iron ions) as promoter. The polymerizations are stopped by chelation of the iron present. Additional monomer is added to the polymerization to avoid formation of low molecular weight polymer. Upon restart metal ions are added to the polymerization mixture.