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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 1067-1072 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Kinetic equations for the decomposition of S-hydroxymethyl cellulose xanthate in the presence of acid and formaldehyde are derived. The assumed mechanism involves an equilibrium between the S-hydroxymethyl cellulose xanthate and cellulose xanthic acid and xanthate ion. Decomposition appears to proceed via interaction between the cellulose xanthate ion and hydrogen ion which form an activated complex that subsequently decomposes to cellulose and carbon disulfide. The equations derived show the proper dependence on acid and formaldehyde concentrations. An estimate of the equilibrium constant between cellulose xanthate and S-hydroxymethyl cellulose xanthate is calculated from the rate constants.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An exploratory investigation of the kinetics of the polymerization of chlorotrifluoroethylene (I) has been made. Experiments were conducted in bulk, in solution in several solvents, and in the presence of several comonomers. Acetyl peroxide (II) was found to be the most effective of common initiators and was used in most of the experiments. The sealed empoule technique was employed. The bulk polymerization of I is zero order to 60-80% conversion; the rate varies as the 0.7 to 0.8 power of the acetyl peroxide concentration, and the over-all activation energy is 17 kcal./mole. The solution polymerization in benzene appears to be first order in monomer; in other solvents the order was not ascertained. The rate and activation energy in solution are solvent dependent and there appears to be an inverse relationship between the rate of polymerization of I in a solvent and the rate of decomposition of II in that solvent. The rate of decomposition of II was measured in a number of solvents and found to vary widely and to parallel, roughly, the rate of decomposition of benzoyl peroxide. The polymerization rate of I in solution is also c. 0.7 order in acetyl peroxide, but was 0.5 order in Porofor N in limited experiments. From copolymerization experiments with styrene, vinyl acetate and methyl methacrylate values of Q of 0.025, 0.025, and 0.016, and of e of 1.4, 2.0, 1.4, respectively, were inferred, in the Q-e scheme of Alfrey and Price. These results above are discussed in the light of polymerization theory.
    Additional Material: 5 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 353-353 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 21 (1956), S. 546-546 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 485-494 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A cellulose pulp of about 550 D.P. was readily dissolved in a combination of (CH2O)x/DMSO to afford an initial 6/6/88 cellulose/(CH2O)x/DMSO composition solution. The concentration of formaldehyde was found to be a function of solution heating time and temperature. The solutions were microscopically free of gels and undissolved cellulose fibers. Cellulosic articles such as fibers and films are easily regenerated from these cellulose solutions in the presence of coagulants such as methanol or water. Fibers with high wet modulus, intermediate tenacity, and low elongations were produced from these regenerations systems. Fibers have been spun with conditioned and wet tenacities as high as 2.9 and 2.1 g/d, respectively, with wet modulus (at 5% elongation) as high as 1.3 g/d and solubility in 6.5% NaOH in the low range of 3.0%-15%. In many respects, these fibers are comparable to those produced in the viscose process. However, the low elongations of these fibers probably would not permit normal textile processing. The cellulose/(CH2O)x/DMSO solutions were modified with compounds containing reactive N—H functional groups which are known to react with excess formaldehyde to yield the corresponding N-methylol derivatives. However, the resulting fiber physical properties were not significantly improved compared to those obtained from unmodified cellulose solutions. Addition of acrylic acid derivatives such as methyl acrylate, butyl methacrylate, or acrylonitrile to the cellulose solutions did not result in the formation of the expected 1,4-type adducts.
    Additional Material: 2 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 4 (1995), S. 481-496 
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of irreversible reactions between polymer chains of different molecular weights are studied, with emphasis on the case of highly reactive end groups. We calculate the rate constant k(N, M) for reaction between chains of lengths N and M respectively, in dilute and semi-dilute solutions and in the melt. In all cases, k(N, M) is dominated by the shortest chain: the limit k(N) ≡ k(N, ∞) is well-defined and scales as if both chains were of length N. In dilute solutions k(N, M) obeys mean field theory, being proportional to the equilibrium reactive group contact probability. For melts and concentrated solutions, k(N, M) follows diffusion-controlled laws: k(N, M) ≈ (RN3/τN)ƒ(M/N) where RN and τN are the coil size and relaxation time of the shortest chain N, and ƒ(M/N) is a cross-over function describing the approach to the asymptotic form k(N) for M/N ≫ 1. We calculate the leading contributions to this cross-over function, which has universal forms depending on the concentration regime. The implications of these results for high-conversion free-radical polymerization are discussed.
    Additional Material: 4 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 19 (1985), S. 991-1010 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 7 (1969), S. 794-795 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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