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  • 1965-1969  (7)
  • 1
    Electronic Resource
    Electronic Resource
    Polymerization of amino acid derivatives by polymer catalysts. I. Polymerization by poly-2-vinylpyridine (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 917-924 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerizations of D,L-β-phenylalanine, p-nitro-D,L-β- phenylalanine, and o,p-dinitro-D,L-β-phenylalanine NCA's were carried out with the use of α-picoline or poly-2-vinyl-pyridine as initiator. Polymerizations induced by the polymer catalyst were always faster than those with α-picoline in the same base concentrations. Furthermore, the polymer effect was more marked when the number of nitro groups in the NCA's increased. It was considered that the polymer catalyst interacts with the NCA's primarily by hydrogen bonding and increases the effective concentration of NCA along the chain. The increase of the NCA concentration in the vicinity of the polymer catalyst wits also achieved through charge-transfer complexes between nitrophenyl groups in the NCA's and pyridine groups in the polymer catalyst. As the polymer chain is flexible, a collision between an adsorbed NCA and a pyridine unit in the same polymer chain is favored, thus increasing the polymerization rate.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1969.360070607
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Polymerization of amino acid derivatives by polymer catalysts. II. Polymerization by copolymer catalysts containing a tertiary amine as a component (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 925-936 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerizations of D,-Lβ-phenylalanine NCA, p-nitro-D,L-β-phenylalanine NCA, and o,p-dinitro-D,L-β-phenylalanine NCA were investigated, homopolymers and copolymers of N-vinyl-2-ethylimidazole or 2-Vinylpyridine being used as catalysts. When N-vinylpyrrolidone and N,N-diethylacrylamide, which are capable of forming hydrogen bonds with the NCA's, were used as comonomers with N-vinyl-2-ethylimidazole, the copolymer catalysts were found to bring about a faster polymerization than poly-N-vinyl-2-ethylimidazole. However, when styrene, which has no particular interaction with the NCA's, was used as a comonomer with 2-vinylpyridine, the copolymer catalyst was found to give a slower polymerization than poly-2-vinylpyridine. Electronic spectroscopy showed that the charge-transfer complex between copolymer catalysts and the NCA's plays an important role in the polymerization. The experimental results are discussed in terms of the effectiveness of the copolymer catalysts for forming hydrogen bonds or charge-transfer complexes with the NCA's.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1969.360070608
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Polymerization of amino acid derivatives by polymer catalysts. III. Chain effect polymerization induced by poly(N-ethylglycine) diethylamide (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 937-947 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of D,L-β-phenylalanine NCA induced by preformed polyi(N-ethylglycine) diethylamide having a terminal secondary amino group was investigated. The polymerization was much faster than the same reaction initiated by a low molecular weight amine of similar base strength. Hence, the chain effect is operative with poly (N-ethylglycine) diethylamide as well as polysarcosine diethylamide, with which Bamford et al. found the chain-effect mechanism. The polymerization rate was dependent on the degree of polymerization of the polymer catalyst. The rate enhancement was attributed to adsorption of the NCA onto the amide carbonyl groups of the polymer chain by the formation of hydrogen bond. In going from polysarcosine diethylamide to poly (N-ethylglycine) diethylamide, the absorptivity of NCA on on the polymer chain was little affected. However, the reaction between an adsorbed NCA and a terminal base was more difficult with poly (N-ethylglycine) diethylamide than with polysarcosine diethylamide. This may be related to differences in flexibility of the polymer chain.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1969.360070609
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Free radicals observed in the vinyl ether-iodine system (1967)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 5 (1967), S. 449-451 
    Details
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1967.110050602
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  • 5
    Electronic Resource
    Electronic Resource
    Cationic copolymerization of isobutene. III. Solvent effect in cationic copolymerization of isobutene with styrene in mixed solventsFor the previous paper, see Imanishi et al.1 (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 2455-2474 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Copolymerizations of isobutene (M1) and styrene (M2) were carried out at -78°C. with the use of titanium tetrachloride as the catalyst in n-hexane-methylene chloride mixed solvents of various compositions. A great variation of r1, r2 was observed. In n-hexane r1 〈 1 and r2 〉 1, in methylene chloride r1 〉 1 and r2 ≃ 1, and in the mixed solvents both r1 and r2 were greater than unity. These experimental facts were interpreted on the basis of a large difference between the reactivities of isobutene cation and styrene cation. A values, on which the discussion of the decrease in the degree of copolymer polymerization can be based, were maximal in n-hexane and decreased with increasing ratio of methylene chloride in the mixed solvent. This is characteristic of the styrenetype monomer transfer reaction.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030705
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    α-Polypeptide synthesis by the hydrogen-migration polymerization of trans-p-nitrocinnamide (1969)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 7 (1969), S. 773-778 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1969.150070230
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  • 7
    Electronic Resource
    Electronic Resource
    Cationic polymerization of cyclic dienes. V. Polymerization of the methylcyclopentadieneFor Part IV see Kohjiya et al.1 (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 6 (1968), S. 809-820 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methylcyclopentadiene (MCPD) has been polymerized with cationic catalysts in toluene solution at -78°C. to a white powdery polymer, whose intrinsic viscosity in benzene solution at 30°C. ranged from 0.1 to 0.5. The comparison of the rate of homopolymerization of MCPD with that of cyclopentadiene (CPD) and the copolymerization of MCPD and CPD indicated that MCPD is much more reactive than CPD. It was suggested that the high stability of cycloalkenyl cation is responsible for the high reactivity of cyclic dienes. Infrared and NMR spectroscopy on polymethylcyclopentadiene showed that almost all of the monomer units in polymethylcyclopentadiene produced under the present conditions have a trisubstituted double bond. The mechanism of the initiation reaction in the polymerization of cyclic dienes is also discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.150060410
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