Free-radical addition polymerization gelation

Addition Polymerization. Gelation by addition polymerization involves a chain reaction in which a free radical is capable of reacting to open the double bond of a vinyl monomer resulting in polymerization by linear addition of these units. 

Free Radical Polymerization. In situ polymerization reactions of the monomers added to metal salt solution other than Pechini process were proposed. They utilize free radical polymerization of acrylamide (Gotor, 1993 Rao, 1995 Sin, 2000, 2002) or acryUc add (Mani, 1992). The gelation in a usual synthesis occurs due to the reaction between acrylamide and N- N= methylene-bis-acrylamide. Free radicals initiating the polymerization are created by hydrogen peroxide or azobisisobutyronitrile. Just solvated copper ions strongly inhibit polymerization and sufficient amount of EDTA (Sin, 2000) or dtric add (Gotor, 1993 Rao, 1995) should be added to chelate copper and possibly other metals. The clear advantage of this method is that in contrast to Pechini-type process, which enploys reversible polyesterification reaction, the polymer formation by free radical mechanism is irreversible process that can be conducted, in addition, at low temperatures. 

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