The homopolymer brushes of polyacrylamide(PAAM) on spherical silicon gel were synthesized by atom transfer radical polymerization(ATRP). The silicon gel initiator was prepared by self-assemble. Utilizing these modifie...The homopolymer brushes of polyacrylamide(PAAM) on spherical silicon gel were synthesized by atom transfer radical polymerization(ATRP). The silicon gel initiator was prepared by self-assemble. Utilizing these modified silicon gel as the substrate, a kind of novel inorganic-organic hybrid material with the polymer metal complex was synthesized. The result of ESR indicates that the inorganic/organic hybrid material with the polymer metal complex based on silicon gel possesses well paramagnetis.展开更多
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
A new catalyst,iron(Ⅱ) chelate of the schiff base derived from β-Ala and picoline,was successfully used for atom transfer radical polymerization.The reaction was carried out at 90℃ in bulk with ethyl 2-bromo-2-ethy...A new catalyst,iron(Ⅱ) chelate of the schiff base derived from β-Ala and picoline,was successfully used for atom transfer radical polymerization.The reaction was carried out at 90℃ in bulk with ethyl 2-bromo-2-ethylpropionate as the initiator.The molecular weight of the resulting polymer increases with increasing monomer conversion.The molecular weight distribution is not narrow(PDI=1.5～1.7),and the value of molecular weight detected is in good accordance with the calculated.The molecular weight distribution is 1.13 with the addition of 10% DMF.展开更多
The atom transfer radical polymerization of styrene was carried out with an α-haloketone, 2-bromocyclohexanone, as the initiator in the presence of CuBr/Cu/2,2′-bipyridine or CuBr/ N,N,N′,N″,N″-pentamethyldiethyl...The atom transfer radical polymerization of styrene was carried out with an α-haloketone, 2-bromocyclohexanone, as the initiator in the presence of CuBr/Cu/2,2′-bipyridine or CuBr/ N,N,N′,N″,N″-pentamethyldiethylenetriamine catalytic system. The polymerization proceeded in a living fashion with that the number average molecular weight increased linearly with the increase of monomer conversion and the polydispersity was relatively low through the polymerization process, especially with CuBr/N,N,N′,N″,N″-pentamethyldiethylenetriamine as the catalyst. The initiation efficiency of 2-bromocyclohexanone in both catalysis systems was about 80%. 1H NMR and 13C NMR verified the presence of 2-oxocyclohexyl and bromine atom at the both ends of polystyrene chains respectively, which were derived from the 2-bromocyclohexanone.展开更多
文摘The homopolymer brushes of polyacrylamide(PAAM) on spherical silicon gel were synthesized by atom transfer radical polymerization(ATRP). The silicon gel initiator was prepared by self-assemble. Utilizing these modified silicon gel as the substrate, a kind of novel inorganic-organic hybrid material with the polymer metal complex was synthesized. The result of ESR indicates that the inorganic/organic hybrid material with the polymer metal complex based on silicon gel possesses well paramagnetis.
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.
文摘A new catalyst,iron(Ⅱ) chelate of the schiff base derived from β-Ala and picoline,was successfully used for atom transfer radical polymerization.The reaction was carried out at 90℃ in bulk with ethyl 2-bromo-2-ethylpropionate as the initiator.The molecular weight of the resulting polymer increases with increasing monomer conversion.The molecular weight distribution is not narrow(PDI=1.5～1.7),and the value of molecular weight detected is in good accordance with the calculated.The molecular weight distribution is 1.13 with the addition of 10% DMF.
文摘The atom transfer radical polymerization of styrene was carried out with an α-haloketone, 2-bromocyclohexanone, as the initiator in the presence of CuBr/Cu/2,2′-bipyridine or CuBr/ N,N,N′,N″,N″-pentamethyldiethylenetriamine catalytic system. The polymerization proceeded in a living fashion with that the number average molecular weight increased linearly with the increase of monomer conversion and the polydispersity was relatively low through the polymerization process, especially with CuBr/N,N,N′,N″,N″-pentamethyldiethylenetriamine as the catalyst. The initiation efficiency of 2-bromocyclohexanone in both catalysis systems was about 80%. 1H NMR and 13C NMR verified the presence of 2-oxocyclohexyl and bromine atom at the both ends of polystyrene chains respectively, which were derived from the 2-bromocyclohexanone.
