Radical-Initiated (Co)polymerization of Methacrylates in the Presence of Organometallic Iron Complexes

Resumo

The effect exerted by organometallic iron complexes (ferrocene, tricarbonyl cyclooctatetraene iron, and dimer cyclopentadienyldicarbonyl iron) on the benzoyl peroxide initiated homo- and copolymerization of methyl methacrylate and n-butyl methacrylate was studied. The ligand surrounding in the organometallic complexes influences the shape of the kinetic curves of the methyl methacrylate and n-butyl methacrylate polymerization. In the presence of organometallic iron complexes, the copolymerization constants are close to unity. That is, the azeotropic copolymerization occurs, with the copolymer composition equal to the composition of the monomer mixture and with the random distribution of monomeric units in the copolymer chain. On the other hand, the presence of metallocenes influences the microstructure and molecular-mass characteristics of the copolymers. These changes are due to the formation of macromolecules with the participation of both free radicals and coordination-active polymerization sites formed in the presence of organometallic complexes.