Well-defined comblike atactic polystyrene functionalized with hydroxyl groups was synthesized via living/controlling radical polymerization promoted by metallocene complexes in the presence of poly(phenyl glycidyl ether)-co-formaldehyde as the initiator and Sn as a reducing agent. The effect of the polymerization conditions, such as the ratio of initiator to monomer, temperature, and polymerization time, and the structure of the metallocene complex on the polymerization process were investigated. The resulting polymers were characterized by gel permeation chromatography, multiangle laser light scattering, H-1-NMR, and C-13-NMR. The results show that the polymer had a narrow molecular weight distribution in the range 1.1.-1.4 and the number-average molecular weight of the polymer linearly depended on the monomer conversion within the polymerization timescale, which confirmed that living radical polymerization characteristics prevailed in the polymerization process. Both the number of arms and the number of hydroxyl groups in each polymer molecule were about four, which suggested that they arose from the epoxy functional groups of the initiator. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 1574-1580, 2010

The advances in homopolymerization of polar monomers and copolymerization of nonpolar monomers with polar monomers based on CGC catalyst,half-metallocene catalyst,bis-metallocene catalyst,multinuclear metallocene catalyst,bridged metallocene catalyst,and non-metallocene catalyst are reviewed. The mechanism of polar monomer polymerization promoted by metallocene catalysts includes living radical polymerization and coordination polymerization.Polymer of polar monomer and copolymer of polar monomer with nonpolar monomer are prepared via metallocene catalysts. It not only expands the application of metallocene catalysts in polymer science,but also develops a kind of polar polyolefin resin featuring new performance.

The development in catalyst for broad or bimodal molecular weight distribution polyethylene prepared with the process of single-reactor was described. According to the composition and structure of the catalyst,the catalytic systems were classified as multi-component composite catalyst and mono-component catalyst. The multi-component composite catalysts were divided into metallocene/Ziegler-Natta composite catalyst,different metallocene composite catalyst,chromium based/Ziegler-Natta composite catalyst,metallocene/late transition metal composite catalyst,non-metallocene single site/metallocene composite catalyst,non-metallocene single site/Ziegler-Natta composite catalyst and different late transition metal composite catalyst. The multi-composite catalyst acted as individual active species,which had different kinetic responses,such as different propagation,termination,and transfer rate constants,and as a result,produced a blend of polymeric chains with two or more predominant molecular masses in ethylene polymerization via the process of single-reactor. The mono-component catalysts involved mononuclear metallocene catalyst,multinuclear metallocene catalyst and late transition metal catalyst and other mono-component catalyst. The mono-catalyst which was able to come into being various catalytic active centers could produce polyethylene with broad or bimodal molecular weight distribution in a single-reactor. To form different active species of the mono-component catalyst was probably resulted from that the catalyst was immobilized on different chemical or physical environmental supports and the center metal of the catalyst was coordinated or reacted with ligand,ancillary ligand cocatalyst as well as additive.

A kind of novel bridged nonmetallocene catalysts was synthesized by the treatment of N,N-imidazole and N,N-phenylimidazole with n-BuLi, and MCl4 (M = Ti, Zr) in THF. Those catalysts were performed for ethylene polymerization after activated by methylaluminoxane (MAO). The effects of polymerization temperature, Al/M ratio, pressure of monomer, and concentration of catalysts on ethylene polymerization behaviors were investigated in detail. Those results revealed that the catalyst system was favorable for ethylene polymerization with high catalytic activity. The polymer was characterized by 13C NMR, WAXD, GPC, and DSC. The result confirmed that the obtained polyethylene featured broad molecular weight distribution around 20, linear structure, and relative low melting temperature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 33–37, 2008

Polybutene-1 was synthesized stereoselectively with the precursor η5-(pentamethyl-cyclopentadienyl) tribenzyloxide titanium (Cp*Ti(OBz)3) and methylaluminoxane (MAO). The effects of polymerization conditions, trimethyl alumina (TMA) content in MAO and temperature on the crystalline and molecular weight of the products, and catalytic activity were investigated. The structural properties of the polybutene-1 were characterized with 13C NMR and WAXD.