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  • 1965-1969  (33)
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Material
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Year
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  • 11
    Electronic Resource
    Electronic Resource
    Trioxane formation in the solid-state polymerization of tetraoxane (1967)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 5 (1967), S. 65-67 
    Details
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1967.110050111
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  • 12
    Electronic Resource
    Electronic Resource
    A simple index of copolymerizability (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 6 (1968), S. 841-847 
    Details
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.110061204
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  • 13
    Electronic Resource
    Electronic Resource
    Solvent effects in anionic copolymerization. II. Molecular orbital treatment for the pair: Styrene-methylstyrene (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 2215-2222 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A model is proposed for the transition state of the anionic copolymerization of styrene and p-methylstyrene in hydrocarbon solvent with lithium counterion. An LCAO-MO treatment which considers the effect of the positive counterion on the negative chain end is used to calculate the electrostatic and the π electron resonance contributions to the activation energies of the four propagation reactions. The electron contributions to the activation energies are also calculated for the propagation reactions of free ions, i.e., in the absence of a counterion. The previously determined rate constants in benzene and tetrahydrofuran are then compared with the results of these calculations.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030610
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  • 14
    Electronic Resource
    Electronic Resource
    Cationic polymerization α,β-disubstituted olefins. Part I. Cationic copolymerization of β-methylstyrenes (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 2567-2578 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Steric and electronic effects of the β-methyl group on monomer reactivity have been studied by copolymerization of styrenes and β-methylstyrenes. Steric hindrance of the β-methyl group in the transition state of homopolymerization is so great that the rate of the propagation reaction is considered to be depressed by as much as 1/10-1/20 of the corresponding styrene derivatives. In contrast to this, steric hindrance of the β-methyl group in cross propagation reactions with styrene is found to be very small. The monomer reactivity itself of β-methylstyrenes is a little lower than that of corresponding styrenes. This lowered reactivity of β-methylstyrenes is considered to be due to the electronic effect of the β-methyl group.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030714
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  • 15
    Electronic Resource
    Electronic Resource
    Penultimate effect in stereospecific polymerization by ionic mechanism (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 3729-3739 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: To clarify the penultimate effect in the stereospecific polymerization by ionic catalysts, the relationship between the steric structure of the polymer and polymerization conditions was studied for α-methylstyrene (αMS), methyl vinyl ether (MVE), and methyl methacrylate (MMA) from our result and literature results. Two possible probabilities of an isotactic addition considering the penultimate effect, Pii and Psi, are compared. We define the α value as Psi = αPii. The greater the deviation of the α-value is from unity, the greater the penultimate effect. It is shown that the α value in a given monomer is constant for a wide range of tacticity in the various conditions. In αMS, the α value is unity and there is no penultimate effect. Otherwise, in the MVE-BF3.-O(C2H5)2 system, α is 0.7 and the penultimate effect is present. When MMA is polymerized by alkali alkyl, the α value is changed by the kind of alkali metal, that is, α values in toluene solution are 0.45, 0.65, and 0.75 for Li, Na, and K, respectively.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100031105
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  • 16
    Electronic Resource
    Electronic Resource
    NMR studies on the stereospecific polymerization of methyl vinyl ether. Part II. Polymerization by sulfuric acid-aluminum sulfate complex: Enantiomorphic catalyst sites model (1967)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 5 (1967), S. 863-875 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Highly crystalline poly(methyl vinyl ether) (PMVE) was produced in toluene in a temperature range of 0 to -20°C. with the use of sulfuric acid-aluminum sulfate complex (SA catalyst). It was found from the NMR spectra that these polymers contained more than 50% of the triad isotactic fraction and the melting point of the unfractionated polymer was about 130°C. However, PMVE containing a large amount of the isotactic fraction was insoluble in nitromethane, so the triad tacticity of highly crystalline PMVE could not be quantitatively determined. The molecular weight of PMVE increased with increasing conversion and increasing polymerization temperature. This behavior is different from that in metal halide catalysts. Also, the stereoregularity of PMVE decreased with increasing monomer concentration. However, addition of a polar solvent and increasing the polymerization temperature had little effect on the stereoregularity of the polymer. The increase in the isotactic fraction at high catalyst concentration and the difference in the monomer composition in the copolymerization of methyl vinyl ether with 2-chloroethyl vinyl ether by SA catalyst from that obtained by BF3·O(C2H5)2 suggest that the absorption of MVE on a catalyst surface is an important step in the propagation step by SA catalyst. The fraction of the triad tacticity calculated from the enantiomorphic catalyst sites model8 coincided with the experimental results. This fact shows that the steric structure of the adding monomer is determined only by the nature of the catalyst irrespective of the nature of a growing chain end. It is concluded, on considering also the results of the previous paper, that completely different factors can control the steric structure of a polymer even for the same monomer when different catalysts are used.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1967.150050413
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  • 17
    Electronic Resource
    Electronic Resource
    NMR studies on the stereospecific polymerization of methyl vinyl ether. Part I. Polymerization by metal halides: Penultimate effect (1967)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 5 (1967), S. 849-862 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl vinyl ether (MVE) was polymerized under various conditions by BF3·O(C2H5)2 and SnCl4·CCl3CO2H catalysts. The effect of polymerization conditions on the steric structure of poly(methyl vinyl ether) (PMVE) was studied by NMR spectra. It was found that the triad isotacticity of PMVE decreased and the syndiotacticity and heterotacticity increased with increasing polarity of the solvent and increasing polymerization temperature. This result coincided with the qualitative conclusion estimated from softening point and infrared spectra. However, the variation of tacticity by the change of the polarity of a solvent was not so large as expected. There was no large difference between the behavior of BF3·O(C2H5)2 and SnCl4·CCl3CO2H as catalysts. From the relation between the difference of free energy of monomer addition due to the steric structure of the polymer and the polymerization temperature, it was concluded that the penultimate effect really existed and was due to only the difference in enthalpy in the MVE-BF3. O(C2H5)2 or MVE-SnCl4·CCl3CO2H systems. The penultimate effect was not greatly changed by the polymerization conditions in these systems.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1967.150050412
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  • 18
    Electronic Resource
    Electronic Resource
    Cationic polymerization of cyclic olefins (1966)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 4 (1966), S. 869-879 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization and the polymerizabilities of indene, benzofuran, and 1,2-dihydronaphthalene are discussed from the point of view of ring strain, ring stabilization, and steric hindrance in the transition state. Monomer reactivities of these olefins were estimated from copolymerization with styrene and from the rate of addition of iodine bromide in acetic acid. Rates and degrees of polymerization are compared with monomer reactivities and resonance energies of indene, 1,2-dihydronaphthalene, and benzofuran as a measure of ring strain and stabilization. It is found that indence is 1.5-2.0 times more reactive than styrene. This high reactivity of indene is attributed to the ring strain in the monomer state and to the low amount of steric hindrance in the transition state of the coplanar five-membered cyclic olefin. 1,2-Dihydronaphthalene is strained and therefore reactive, but propagation to higher molecular weight products is impeded due to the steric hindrance. The reactivity of benzofuran is decreased by conjugative stabilization of C=C double bonds at the reaction site.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1966.150040413
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  • 19
    Electronic Resource
    Electronic Resource
    Polymerization of tetraoxane at low concentration catalyzed by BF3·O(C2H5)2 (1967)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 5 (1967), S. 2997-3007 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the solution polymerization of tetraoxane catalyzed by BF3·O(C2H5)2, trioxane and methanol-insoluble polymer were produced. However, the amounts of these products depend on the nature of solvent used. A critical concentration of tetraoxane is observed for the formation of methanol-insoluble polymer; at less than this critical concentration of tetraoxane no methanol-insoluble polymer is obtained, but trioxane is preferentially produced. This critical concentration of tetraoxane is higher in a more polar solvent, so the amount of methanol-insoluble polymer produced decreases and the amount of trioxane produced increases with increasing the polarity of solvent used. These results may be explained in terms of a stabilization of the active center leading to formation of trioxane by a solvation with solvent.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1967.150051203
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  • 20
    Electronic Resource
    Electronic Resource
    Cationic polymerization of the geometrical isomers of β-methylstyrene and anetholeThis is the sixth in a series of papers, “Cationic Polymerization of α,β-Disubstituted Olcfins.” (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 6 (1968), S. 1825-1832 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cationic polymerization of the geometrical isomers of β-methylstyrene and anethole (p-β-methoxy-β-methylstyrene) was studied in order to clarify the relation between the geometrical structure of the α,β-disubstituted olefins and their monomer reactivities, subsequent to previous work. Polymerization was carried out in toluene or ethylene dichloride with stannic chloride at 0°C. trans-β-Methylstyrene was 1.3 to 1.5 times more reactive than cis-β-methylstyrene to the styrene carbonium ion; copolymerization between the trans and the cis isomers of β-methylstyrene showed little difference in monomer reactivity. By contrast, the cis anethole was 1.5-2.0 times more reactive than the trans, according to copolymerization between the two isomers together. The lower reactivity of the cis-β-methylstyrene could be explained by steric hindrance in the cis isomer, proposed by Overberger et al.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.150060704
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