Mechanistic studies of methyl methacrylate polymerization in the presence of cobalt complex with sterically-hindered redox-active ligand

• Published in: Journal of polymer research Vol. 23; no. 11; p. 1
• Main Authors: Kolyakina, Elena V., Grishin, Ivan D., Poddel’sky, Andrey I., Grishin, Dmitry F.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.11.2016; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Original Paper; Polymer Sciences; Dissociation-combination; Radical polymerization; Poly (methyl methacrylate); Degenerative chain transfer; Catalytic chain transfer; Iminosemibenzoquinone; Cobalt complexes
• ISSN: 1022-9760; 1572-8935
• DOI: 10.1007/s10965-016-1114-2

The influence of bis[4,6-di- tert -butyl- N -(2,6-dimethylphenyl)- o -iminobenzosemiquinono]cobalt (II) on radical polymerization of methyl methacrylate initiated by AIBN at 70–90 °C was studied. The introduction of cobalt complex bearing redox ligands into reaction media allows to provide polymerization of methyl methacrylate without self-acceleration with linear increase of molecular weight with conversion giving polymers with relatively low molecular weight distribution. The results of IR and NMR spectrometry and MALDI mass spectroscopy measurements show that the possibility of β-hydrogen transfer between complex and propagating radical during polymerization is minimal. The electron donating additives as tert .-butyl amine and pyridine have no activating effect on polymerization. The results of our experiments provided at different concentrations of initiator show that polymerization proceeds via degenerative chain transfer mechanism.