Aminomethylene phosphonic acid–ceric ion redox systems for aqueous polymerization of vinyl monomers

Aminomethylene phosphonic acids, such as amino tri(methylene phosphonic acid) (ATMP), 1-hydroxy-ethylidene-1,1-diphosphonic acid (HEDP), diethylene triamine penta(methylene phosphonic acid) (DTPMPA), N,N-di(methylene phosphonic acid) ethanol amine (DMPEA), N,N-di(methylene phosphonic acid)-N-methylamine (DMPAMA), N-oxo-N,N,N-tri(methylene phosphonic acid) (OTMPA), and ceric ammonium nitrate redox systems are used for the polymerizations of acrylonitrile, vinyl acetate, acrylic acid and acrylamide. The effects of concentration of ceric ion and aminomethylene phosphonic acid on the yield and molecular weight show that oxidative termination reaction becomes important at higher ceric concentration and considerable chain-transfer reaction occurs at higher ATMP concentration. The redox reaction in the complex of ceric ion and ATMP forms a primary radical on an ATMP molecule, which in turn initiates polymerization to give polymer containing amino tri(methylene phosphonic acid) chain end.