Synthesis of polystyrenes with arylseleno groups at the terminal bond, by the free radical polymerization of styrene in the presence of diaryl diselenides, and their conversion to end functional polymers

Free radical polymerization of styrene in the presence of diphenyl diselenide, initiated by 2,2'-azobisisobutyronitrile (AIBN) at 60 degrees C, was investigated. Diphenyl diselenide worked as a chain transfer agent and its chain transfer constant was estimated to be 28.0, which is remarkably larger than that of the sulphur analogue, diphenyl disulphite. Polymerization with bis(p-tert-butylphenyl) diselenide gave a polystyrene containing a 1-cyano-methylethyl group at the alpha-end and an arylseleno group at the omega-end, respectively, and the degree of functionality was nearly 1.0. The arylseleno group at the omega-end was reduced quantitatively by the reaction with tri-n-butyltin hydride. This group was also eliminated by treatment with hydrogen peroxide, to give an end functional polystyrene with a carbon-carbon double bond at the omega-end. Further, this double bond was converted to an epoxy group by the oxidation with m-chloroperbenzoic acid. (C) 1999 Elsevier Science Ltd. All rights reserved.