Cobalt Mediated Radical Polymerization of 4-Bromo-2, 6-Dimethyl Phenol and Its Copolymerization with Poly (dimethyl siloxane) in the Presence of Co(acac)₂: DMF Catalyst

Abstract

Poly(phenylene oxide) was synthesized from 4-bromo-2,6-dimethylphenol (BDMP) in the presence of cobalt acetoacetonate (Co(acac)₂) catalyst with dimethyl formamaide (DMF) ligand. The reaction was initiated with benzoyl peroxide at 60 °C. The BDMP reacted with poly(dimethyl siloxane) (PDMS) in a novel controlled copolymerization reaction with good yield. The solid polymer indicated a narrow molecular weight distribution (PDI ≈ 1.28). This monomer copolymerized further with styrene and methyl methacrylate, extending the scope of the controlled radical polymerization from the brominated dialkyl aromatic phenols to a number of various monomers. The synthesis of such polymers, copolymers, and block copolymers are considered to be an important step in the preparation of novel, thermally stable block copolymers with a wide range of chemical compositions and structures, such as rotaxanes. The reactivity ratio for VAc and BDMP monomer pairs was calculated from Mayo-Lewis (r_PDMS = 0.293, r_BDMP = 0.485), Kelen-Todous (r_PDMS = 0.289, r_BDMP = 0.476) and Finemann-Rose models (r_PDMS = 0.299, r_BDMP = 0.481).