a review of redox and thermal initiation in free radical polymerization

generation of free radical species is an essential element of all free-radical polymerization reactions. a lot of organic molecules are stable at moderate and elevated temperatures. therefore, in some reactions the addition of stable free radical which shows very little or almost no tendency in self-combination is of great importance, as free radical species are aimed to initiate reactant molecules in a specific reaction. the radical species differ in a wide range from organic to inorganic chemicals. these molecules are chosen based on monomers and desired reactions. there are a vast range of organic peroxides and azo compounds as well as redox pairs that are important in resin and polymer industries. the way to generate these free radicals varies from mild to harsh conditions. in this review, giving some examples of thermal and redox pair initiators, some newly employed metal-ion-organic –compound redox systems for polymerizations in aqueous media are presented.