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The new aminosilane compounds including Dimorpholindimethoxysilane (Donor-Pm), Di (1-methylpiperazine) dimethoxysilane (Donor-Pz) and Di (isopropylpiperazine) dimethoxysilane (Donor-Pi) were firstly synthesized and then employed as external donors for propylene polymerization with MgCl-supported Ziegler-Natta catalyst, compared with dipiperidine dimethoxysilane (Donor-Py). The effects of the aminosilane external donors on the catalytic activity, hydrogen response, and molecular weight distribution, crystalline ability, thermal property, isotactic sequence length, isotactic sequence distribution of polypropylene were studied by differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and self-nucleation and annealing (SSA), respectively. It was found that these new aminosilane compounds were conducive to improving the isotacticity of polypropylene and the catalytic activity. The GPC results showed that the molecular weight distribution of polypropylene prepared respectively by Donor-Pz or Donor-Pi with two N atoms on each amino substituent group was broader more than 8.0, especially for Donor-Pi with the large alkyl-substituted group on each nitrogen atom, the molecular weight distribution of polypropylene was about 11.2, which was much broader than that of industrial polypropylene about 4 ~ 5. The DSC results indicated that the degrees of crystallinity of polypropylene prepared by the aminosilane external donors were higher, and the crystallization ability of polypropylene prepared by Donor-Pi was lower but closed to that of polypropylene prepared by Donor-Py. The SSA results indicated Donor-Py and Donor-Pi were conducive to improving the relative contents of the highest isotactic component of polypropylene, and the lamellae thicknesses results showed the sequence length of polypropylene prepared by Donor-Py and Donor-Pi were longer, and the isotactic sequence distribution of polypropylene prepared by Donor-Py and Donor-Pi were broader. The study results showed that the new aminosilane donor Donor-Pi was conducive to improving the stereo-regularity of polypropylene, especially revealing that it was a simple and an effective method to synthesize broad molecular weight distribution of polypropylene by using appropriate aminosilane external donor for propylene polymerization. [ABSTRACT FROM AUTHOR]

MgCl2/TiCl4/diether is a fifth-generation Ziegler-Natta catalyst for the commercial polymerization of propylene. The outstanding features of this catalyst are the high activity and high isotacticity for propylene polymerization without using an external electron donor. In this study, we explored the copolymerization of propylene and 1-octene with MgCl2/TiCl4/diether catalyst. It was found that MgCl2/TiCl4/diether catalyst showed higher polymerization activity and led to greater 1-octene content incorporation, compared with a fourth-generation Ziegler-Natta catalyst (MgCl2/TiCl4/diester). With an increase in 1-octene incorporation in polypropylene chains, the melting temperature, glass transition temperature and crystallinity of the copolymers decreased distinctly. The microstructures of the copolymers were characterized using 13C NMR spectroscopy, and the copolymer compositions and number-average sequence lengths were calculated from the dyad concentration and distribution. This result is very important for the in-reactor polyolefin alloying process, especially for the case of a single catalyst and two-step (or two-reactor) process. Copyright © 2011 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Examines the design of a novel synthetic route used for preparing propylene-styrene copolymer. Catalysis of a propylene copolymerized with a 4-(3-butenyl) styrene by a propylene active catalyst to form a polymer which has a polypropylene main chain and some styryl side groups.

Fivenew alkoxysilanes with different sizes of hydrocarbon substituentswere first synthesized and employed as external donors for propylenepolymerization with a Ziegler–Natta catalyst. The effects ofthese and industrial alkoxysilanes with different sizes of hydrocarbonsubstituents on the microstructure of polypropylene were studied bySSA and 13C NMR. The results showed that isotactic sequencelength of polypropylene increased with the size of R2substituenton alkoxysilanes in the five donor systems, similar to the regularityof molecular weight, isotacticity, and thermal properties of polypropylene.Although the polypropylene produced by double cycloalkane substituentson alkoxysilanes had lower lamellae thickness L1, its contents were the highest. Moreover, excess large volumeof hydrocarbon substituents on alkoxysilanes might be detrimentalto improving isotactic sequence length of polypropylene. Polypropyleneprepared by MIPDMS had a more uniform distribution of the stereodefects,indicating that MIPDMS might be used for the industrial productionof BOPP. [ABSTRACT FROM AUTHOR]

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]