Functionalization of vinyl polymers through polymeric iniferters: synthesis of poly(methyl methacrylate- b-phosphonamide) and poly(styrene- b-phosphonamide)

Abstract

New thermal polymeric iniferters based on poly(thiuram disulphides) bearing polyphosphonamide blocks have been synthesized and characterized. This was realized by synthesizing bis(secondary amine)-terminated polyphosphonamides by reaction of phenyl phosphonic dichloride with piperazine. Chain extension of the resulting macrodiamines through a dithiocarbamylation reaction followed by oxidative coupling gave poly(thiuram disulphides) bearing the phosphonamide function. Thermal polymerization of methyl methacrylate (MMA) and styrene in the presence of these iniferters led to the formation of their block copolymers with phosphonamide through an ‘iniferter’ mechanism. The kinetics of polymerization of MMA over a limited iniferter concentration range were determined at 70, 78, 85 and 95°C and those of styrene at 78°C. The various kinetic parameters pertaining to initiation and primary radical termination were evaluated. In the case of styrene, normal polymerization behaviour was observed. The ‘iniferter’ efficiency was found to increase with temperature. The nature and block length of the resulting copolymers were found to be dependent on the monomer/polymeric iniferter ratio and on the extent of monomer conversion. Some of the physical properties of the copolymers were evaluated.