Atom transfer radical polymerization of styrene initiated by α,α dibromotoluene and catalyzed by copper (I) bromide/2,2′ bipyridine was carried out.The produced polymers had narrow molecular weight distributions an...Atom transfer radical polymerization of styrene initiated by α,α dibromotoluene and catalyzed by copper (I) bromide/2,2′ bipyridine was carried out.The produced polymers had narrow molecular weight distributions and controlled molecular weights that were proportional to monomer conversion.In order to show that α,α dibromotoluene is a bifunctional initiator for atom transfer radical polymerization of styrene,polymerization of styrene using a mixture of 1 phenyl ethyl bromide and α,α dibromotoluene initiators was also carried out.The GPC trace of obtained polystyrene exhibited bimodal distribution.The peak appearing at lower elution time corresponds to polymer from α,α dibromotoluene and the other one corresponds to polymer from 1 phenyl ethyl bromide.The ratio of peak molecular weight of the polymer from α,α dibromotoluene to that from 1 phenyl ethyl bromide was found to be close to two,confirming that the polymer from α,α dibromotoluene grows from both ends of the polymer chain.Furthermore,the ratio of the two peak surface area changed with the molar ratio of α,α dibromotoluene to 1 phenyl ethyl bromide.展开更多
文摘Atom transfer radical polymerization of styrene initiated by α,α dibromotoluene and catalyzed by copper (I) bromide/2,2′ bipyridine was carried out.The produced polymers had narrow molecular weight distributions and controlled molecular weights that were proportional to monomer conversion.In order to show that α,α dibromotoluene is a bifunctional initiator for atom transfer radical polymerization of styrene,polymerization of styrene using a mixture of 1 phenyl ethyl bromide and α,α dibromotoluene initiators was also carried out.The GPC trace of obtained polystyrene exhibited bimodal distribution.The peak appearing at lower elution time corresponds to polymer from α,α dibromotoluene and the other one corresponds to polymer from 1 phenyl ethyl bromide.The ratio of peak molecular weight of the polymer from α,α dibromotoluene to that from 1 phenyl ethyl bromide was found to be close to two,confirming that the polymer from α,α dibromotoluene grows from both ends of the polymer chain.Furthermore,the ratio of the two peak surface area changed with the molar ratio of α,α dibromotoluene to 1 phenyl ethyl bromide.
