Ideal Copolymerization

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Koji Masaki - One of the best experts on this subject based on the ideXlab platform.

  • Polymerization of Isoprene with Ni(acac)_2-Methylaluminoxane Catalyst
    Polymer Journal, 1997
    Co-Authors: Kiyoshi Endo, Koji Masaki, Yoshiki Uchida
    Abstract:

    The polymerization of isoprene (IP) with transition metals (MtX) and methylalumoxane (MAO) catalysts was carried out. Nickel(II) acetylacetonate [Ni(acac)_2] in combination with MAO revealed high catalytic activity. The microstructure of the polymers obtained with the Ni(acac)_2-MAO catalyst was mainly cis -1,4-units, and but no 1,2-units were observed, indicating that the polymerization of IP with the Ni(acac)_2-MAO catalyst proceeds through a mainly 4,1-addition mode. From the Copolymerization of styrene (St) and IP with the Ni(acac)_2 and MAO catalyst, monomer-reactivity ratios were estimated to be r _St=1.18 and r _IP=0.88, indicating an Ideal Copolymerization to proceed to give a random copolymer. The IP units in the copolymers consist of mainly cis -1,4-microstructure.

  • Copolymerization of styrene and isoprene with Ni(acac)2-methylalumoxane catalyst
    Macromolecular Rapid Communications, 1995
    Co-Authors: Kiyoshi Endo, Koji Masaki
    Abstract:

    Copolymerization of styrene (St) and isoprene (IP) with nickel(II) acetylacetonate [Ni(acac)2] and methylalumoxane (MAO) catalyst was investigated. It was found that the Ni(acac)2-MAO catalyst is effective for the Copolymerization of St and IP. From the Copolymerization of St (M1) and IP (M2) and IP (M2) with the Ni(acac)2-methylalumoxane catalyst, the monomer-reactivity ratios were determined to be r1 = 1,18 and r2 = 0,88, i.e., Ideal Copolymerization was found to proceed to give perfectly random copolymers without formation of any homopolymer. The microstructure of IP units in the copolymers exhibits high cis-1,4 contents.

Kiyoshi Endo - One of the best experts on this subject based on the ideXlab platform.

  • Polymerization of Isoprene with Ni(acac)_2-Methylaluminoxane Catalyst
    Polymer Journal, 1997
    Co-Authors: Kiyoshi Endo, Koji Masaki, Yoshiki Uchida
    Abstract:

    The polymerization of isoprene (IP) with transition metals (MtX) and methylalumoxane (MAO) catalysts was carried out. Nickel(II) acetylacetonate [Ni(acac)_2] in combination with MAO revealed high catalytic activity. The microstructure of the polymers obtained with the Ni(acac)_2-MAO catalyst was mainly cis -1,4-units, and but no 1,2-units were observed, indicating that the polymerization of IP with the Ni(acac)_2-MAO catalyst proceeds through a mainly 4,1-addition mode. From the Copolymerization of styrene (St) and IP with the Ni(acac)_2 and MAO catalyst, monomer-reactivity ratios were estimated to be r _St=1.18 and r _IP=0.88, indicating an Ideal Copolymerization to proceed to give a random copolymer. The IP units in the copolymers consist of mainly cis -1,4-microstructure.

  • Copolymerization of styrene and isoprene with Ni(acac)2-methylalumoxane catalyst
    Macromolecular Rapid Communications, 1995
    Co-Authors: Kiyoshi Endo, Koji Masaki
    Abstract:

    Copolymerization of styrene (St) and isoprene (IP) with nickel(II) acetylacetonate [Ni(acac)2] and methylalumoxane (MAO) catalyst was investigated. It was found that the Ni(acac)2-MAO catalyst is effective for the Copolymerization of St and IP. From the Copolymerization of St (M1) and IP (M2) and IP (M2) with the Ni(acac)2-methylalumoxane catalyst, the monomer-reactivity ratios were determined to be r1 = 1,18 and r2 = 0,88, i.e., Ideal Copolymerization was found to proceed to give perfectly random copolymers without formation of any homopolymer. The microstructure of IP units in the copolymers exhibits high cis-1,4 contents.

Yoshiki Uchida - One of the best experts on this subject based on the ideXlab platform.

  • Polymerization of Isoprene with Ni(acac)_2-Methylaluminoxane Catalyst
    Polymer Journal, 1997
    Co-Authors: Kiyoshi Endo, Koji Masaki, Yoshiki Uchida
    Abstract:

    The polymerization of isoprene (IP) with transition metals (MtX) and methylalumoxane (MAO) catalysts was carried out. Nickel(II) acetylacetonate [Ni(acac)_2] in combination with MAO revealed high catalytic activity. The microstructure of the polymers obtained with the Ni(acac)_2-MAO catalyst was mainly cis -1,4-units, and but no 1,2-units were observed, indicating that the polymerization of IP with the Ni(acac)_2-MAO catalyst proceeds through a mainly 4,1-addition mode. From the Copolymerization of styrene (St) and IP with the Ni(acac)_2 and MAO catalyst, monomer-reactivity ratios were estimated to be r _St=1.18 and r _IP=0.88, indicating an Ideal Copolymerization to proceed to give a random copolymer. The IP units in the copolymers consist of mainly cis -1,4-microstructure.

A. Valvassori - One of the best experts on this subject based on the ideXlab platform.

  • Infrared Study on the Distribution of Propylene Units in Ethylene—Propylene Copolymers
    Journal of Polymer Science Part C: Polymer Symposia, 2007
    Co-Authors: F. Ciampelli, A. Valvassori
    Abstract:

    An accurate comparison of the infrared spectra of ethylene-propylene copolymers, the infrared spectrum of alternate ethylene-propylene copolymer obtained by complete hydrogenation of natural rubber, and the infrared spectra of various branched hydrocarbons made it possible to find a method for determining the distribution of the propylene sequences in ethylene-propylene copolymers. This method is based on the measurement of the ratio of absorbancies at 10.3 and 10.675μ, which are proportional to the number of propylene units in sequences of two or more units and to isolated propylene units, respectively. A distribution index φ is also defined as a ratio between the number of isolated propylene units and the number of units present in sequences of two or more propylene units. This index is compared with that obtained from the calculation for an Ideal Copolymerization. The comparison suggests that some catalysts give rise to copolymers for which the plot of φ versus propylene units content is very similar to the plot predicted for an Ideal Copolymerization. Some other catalysts yield copolymers for which the plot of φ is somehow different. However, these copolymers contain considerable amounts of (CH2)2 groups (which are not foreseen in the calculations performed for the Ideal Copolymerization) that might be responsible for the anomalous behavior of the φ values.

Arno Kraft - One of the best experts on this subject based on the ideXlab platform.

  • Synthesis and polymerization of 5‐(methacrylamido)tetrazole, a water‐soluble acidic monomer
    Journal of Polymer Science Part A: Polymer Chemistry, 2002
    Co-Authors: Andreas Taden, Alison H. Tait, Arno Kraft
    Abstract:

    The reaction of methacryloyl chloride with 5-aminotetrazole gave the polymerizable methacrylamide derivative 5-(methacrylamido)tetrazole (4) in one step. The monomer had an acidic tetrazole group with a pKa value of 4.50 ± 0.01 in water methanol (2:1). Radical polymerization proceeded smoothly in dimethyl formamide or, after the conversion of monomer 4 into sodium salt 4-Na, even in water. A superabsorbent polymer gel was obtained by the Copolymerization of 4-Na and 0.08 mol % N,N′-methylenebisacrylamide. Its water absorbency was about 200 g of water/g of polymer, although the extractable sol content of the gel turned out to be high. The consumption of 4-Na and acrylamide (as a model compound for the crosslinker) during a radical polymerization at 57 °C in D2O was followed by 1H NMR spectroscopy. Fitting the changes in the monomer concentration to the integrated form of the Copolymerization equation gave the reactivity ratios r4-Na = 1.10 ± 0.05 and racrylamide = 0.45 ± 0.02, which did not differ much from those of an Ideal Copolymerization. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4333–4343, 2002