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  • Chemistry  (6)
  • activation by trialkylaluminum with or without diisopropyldimethoxysilane  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Ethene-propene copolymerization with the MgCl2-supported dichlorobis(4,4,4-trifluoro-1-phenyl- 1,3-butanedionato)titanium catalyst activated by an ordinary trialkylaluminum (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2735-2740 
    Details
    ISSN: 0887-624X
    Keywords: Ti(BFA)2Cl2/MgCl2 catalyst (BFA = 4,4,4-trifluoro-1-phenyl-1,3-butanedione) ; activation by trialkylaluminum with or without diisopropyldimethoxysilane ; copolymerization of ethene with propene ; homogeneity of active species ; homogeneity of copolymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Ti(BFA)2Cl2/MgCl2-Al(C2H5)3 catalyst (BFA = 4,4,4-trifluoro-1-phenyl-1,3-butanedione) modified by DIPDMS (diisopropyldimethoxysilane), which had been proved to yield an extremely high isotactic polypropene in high selectivity, was tested for the copolymerization of ethene with propene. The analysis of resulting copolymers by CFC (cross fractionation chromatography) indicated the formation of a small quantity of ethene-rich copolymers as a byproduct, suggesting that the catalyst possesses not only Ti(III) species but a small portion of Ti(II) species. Whereas, the same catalyst without being modified by an external donor selectively yielded propene-rich random copolymers resulting from Ti(III) species in high yields. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2735-2740, 1998
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Alternating copolymerization of ethylene and 1-octene with meso-[dimethylsilylbis(2-methyl-1-indenyl)]zirconium dichloride-methylaluminoxane as catalyst system (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 18 (1997), S. 883-889 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Copolymerizations of ethylene and α-olefins with homogeneous metallocene catalysts generally give the corresponding random copolymers with narrow molecular mass distributions. In this study, we have conducted the copolymerization of ethylene and 1-octene with the meso-Me2Si(2-Me-1-Ind)2ZrCl2-methylaluminoxane (MAO) catalyst system, and analyzed the microstructure of the resulting copolymers in detail. The content of the alternating [EO] sequence increases markedly with an increase in the feed ratio of 1-octene to ethylene, reaching over 95% under appropriate copolymerization conditions. We have thus succeeded in preparing the first sample of alternating olefin copolymers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1997.030180917
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Structures of polyethylene and copolymers of ethylene with 1-octene and oligoethylene produced with the Cp2ZrCl2 and [(C5Me4)SiMe2N(t-Bu)]TiCl2 catalysts (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 4237-4251 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerization of ethylene and copolymerizations of ethylene with 1-octene and oligoethylene having a vinyl end group were conducted with Cp2ZrCl2 and [(C5Me4)SiMe2N(t-Bu)]TiCl2a as catalysts, and the structures of the resulting polymers were analyzed in detail. The Cp2ZrCl2 catalyst combined with methylalumoxane (MAO) gives polyethylene with vinyl, vinylidene and trans-vinylene groups. The use of Al(iC4H9)3/(C6H5)3C · B(C6F5)4 as cocatalyst produces polyethylene predominantly containing trans-vinylene groups. Polyethylene with vinyl end groups was obtained selectively with [(C5Me4)SiMe2N(t-Bu)]TiCl2—MAO as catalyst. The types and contents of C=C double bonds in polyethylene markedly depend upon the metallocene compound as well as as the cocatalyst. In the copolymerizations the [(C5Me4)SiMe2N(t-Bu)]TiCl2—MAO catalyst system, on the other hand, gives poly[ethylene-co-(1-octene)] with a high content of 1-octene and a polyethylene containing an appreciable amount of long-side-chain oligoethylene.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1996.021971220
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis of MgCl2-supported dichlorobis(4,4,4-trifluoro-1-phenyl-1,3-butanedionato)titanium catalysts with different titanium contents and their application to propene polymerization (1998)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 199 (1998), S. 1495-1499 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Various MgCl2-supported Ti(4,4,4-trifluoro-1-phenyl-1,3-butanedionato)2Cl2 catalysts with different Ti contents (0.017 ∼ 0.002 mmol/g) were synthesized and applied to propene polymerization using triethylaluminium and di-i-propyldimethoxysilane (DIPDMS) as the cocatalyst and external donor, respectively. When polymerization was conducted in the absence of DIPDMS, neither the activity nor the isospecificity of catalyst were dependent upon the Ti content. However, the effect of DIPDMS on the catalyst performance was found to be markedly dependent upon the Ti content, i.e., the addition of DIPDMS to the catalyst with low Ti content caused a prominent increase in the activity for isotactic polymerization. As a result, the present catalyst with low Ti content gave a highly isotactic polypropene with Tm = 169.3°C and [mmmm] 〉 99% in high selectivity (I.I. = 97.7%).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Polymerization of propylene with the [ArN(CH2)3NAr]TiCl2 (Ar = 2,6-iPr2C6H3) complex using R3Al/Ph3CB(C6F5)4 (R = Me, Et, iBu) as cocatalyst (1998)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 19 (1998), S. 597-600 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerization of propylene was conducted at 0 ∼ 150°C with the [ArN(CH2)3NAr]TiCl2 (Ar = 2,6-iPr2C6H3) complex using a mixture of trialkylaluminium (AIR3, R = methyl, ethyl and isobutyl) and Ph3CB(C6F5)4 as cocatalyst. When AlMe3 or AlEt3 was employed, atactic polypropylene (PP) was selectively produced, whereas the use of Al(iBu)3 gave a mixture of atactic and isotactic PP. The isotactic index (I.I.; weight fraction of isotactic polymer) depended strongly upon the polymerization temperature, and the highest I.I. was obtained at ca. 40°C. The 13C NMR analysis of the isotactic polymer suggests that the isotactic polymerization proceeds by an enantiomorphic-site mechanism. It was also demonstrated that the present catalyst shows a very high regiospecificity.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Alternating copolymerization of ethylene and propene with the [ethylene(1-indenyl)(9-fluorenyl)]zirconium dichloridemethylaluminoxane catalyst system (1998)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 19 (1998), S. 337-339 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The copolymerization of ethylene and propene was conducted at -40°C with the [ethylene(1-indenyl)(9-fluorenyl)]zirconium dichloride-methylaluminoxane catalyst system, and the microstructure of the resulting copolymers was analyzed in detail by 13C NMR. The content of alternating [EP] sequences increased markedly with an increase in the feed ratio of propene to ethylene. A poly(ethylene-co-propene) with a proportion of [EP] sequences over 95% was thus obtained under appropriate copolymerization conditions. It was also demonstrated that the alternating ethylene-propene copolymer is stereoregular and isotactic.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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