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Details the development of a catalytic system with high polymeric activity. Intercalation of the cocatalysts, which included methylaluminoxane (MAO, between layers of montmorillonite (MMT) for ethylene oligomerization; Formation of a dual functional catalytic system by adding metallocene catalyst Me2Si(Ind)2ZrCl2 and MAO; Preparation of the PE/MMT nanocomposite by copolymerization of ethylene with α-olefins produced in situ from ethylene; Conclusion that the PE/MMT nanocomposites are stable and have more tensile strength; Temperature of maximum weight loss (Tonset).

Reports two novel Fe(II) diimine complexes that were synthesized. How they generate active catalytic systems when combined with MAO; Finding they oligomerize ethylene with high catalytic activity and high selectivity for α-olefins; The effects of substituents on the aryl ring, reaction temperatures and molar ratios of Al/Fe on catalytic activity and product distribution.

Abstract: The copolymerization of propylene with allyldimethylsilane (ADMS) was carried out with conventional Ziegler–Natta catalyst supported on MgCl2. The effects of the concentration of ADMS in the feed on the polymerization reaction and copolymer properties were investigated. The resulting copolymer PP-co-ADMS was chlorinated to PP–Si–Cl by refluxing the copolymer with SOCl2 in benzene. The chlorinated copolymer was used to initiate ATRP of MMA with CuCl/PMDETA as catalyst to produce graft copolymer PP-g-PMMA, which was characterized with 1H NMR, 13C NMR, GPC and DSC. Polymer blend of iPP/PP-g-PMMA/PMMA was prepared and the results shown that PP-g-PMMA was an effective compatilizer. [Copyright &y& Elsevier]

Abstract: A novel layered calcosilicate (CAS-1) was employed to immobilize an iron-based diimine catalyst 2,6-bis[1-(2,6-diisopropylphenylimino)ethyl]pyridine iron chloride (I) onto it to form a supported catalyst (CC) for the first time. The crystal structure of CAS-1 was determined by X-ray crystallographic analysis in addition to SEM characterization. The CC-catalyzed ethylene polymerization exhibited good catalytic activities with either co-catalyst methylaluminoxane (MAO) or triethylaluminum (TEA). The resulting polyethylenes possessed not only higher molecular weight, melting temperature (T m), and decomposition onset temperature (T onset) than those obtained with its homogeneous counterpart, but also a unique morphology. [Copyright &y& Elsevier]

Abstract: An interference-free tandem catalysis based on iron catalyst and TiCl4/MgCl2, activated by MAO, was used to prepare branched polyethylene by polymerization of ethylene. No obvious deactivation due to the side reaction of catalysts and cocatalysts was detected during the reaction process, which commonly existed in tandem catalytic systems based on conventional Ziegler–Natta catalysts. A series of branched polyethylene with different properties have been prepared by adjusting of reaction temperature, Fe/Ti molar ratio and the amount of MAO used. The alteration of oligomers concentration in the reaction system, by changing of reaction conditions, led to the products with different branching degrees, thus the thermal properties and molecular weight. The products obtained in toluene at lower Fe/Ti ratios exhibited better morphology than those obtained at higher Fe/Ti ratios. [Copyright &y& Elsevier]

NiII, CoII and FeII complexes of 2-(2-pyridyl)quinoxaline were synthesized and used in the ethylene oligomerization with methyl-aluminoxane (MAO) as cocatalyst. The nickel complex system mainly produced α-olefins with good activity, while the cobalt and iron complexes showed only marginal activity. [Copyright &y& Elsevier]

A new method is proposed in which a chromium-based catalyst system containing chromium(III) tris (2-ethylhexanoate) (Cr(EH)3), 2,5-dimethylpyrrole (2,5-DMP), GeCl4 and triethylaluminum (TEA) coated with solid paraffin is used for oligomerization of ethylene. GC-MS and 1H-NMR analyses show that the coated catalyst system prepared via this approach is air-insensitive so it can be stored under ambient conditions. The selectivity for 1-hexene is up to 97.91 wt.%, and only slightly decreases when the catalyst system is exposed in air for 24 h; in contrast, the selectivity is only 35.6% for its non-coated counterpart. XPS reveals that an attachment of atmospheric oxygen to catalyst makes the chemical state of chromium change from Cr3+ to Cr6+. Such a change, in turn, reduces remarkably its selectivity for 1-hexene. [Copyright &y& Elsevier]