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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 3311-3325 
    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: Radiation-induced polymerization of water-saturated styrene (water content 3.5 × 10-2 mole/liter) was carried out in a wide range of dose rate between 1.2 × 103 and 1.8 × 107 rad/sec, and compared with the polymerization of the moderately dried styrene (water content 3.2 × 10-3 mole/liter). Molecular weight distribution curves of the polymerization products showed that they were generally consisted of four parts, namely, oligomers, radical, cationic, and super polymers. Contributions of the four constitutents to the polymerization and the number average degrees of polymerization (DP) of the four kinds of polymers were calculated by the graphical analysis of the curves. The rate of radical polymerization and DP of radical polymers are independent of the water content; the dose rate dependences of the polymerization rate and DP agree with the well known square root and inverse square root laws, respectively, of the radical polymerization of styrene. The rate of ionic polymerization is directly proportional to the dose rate, but it decreases, at a given dose rate, inversely proportional to the water content of styrene. DP of ionic polymer is independent of the dose rate but decreases with increasing water content. The super polymer of DP about 104 is not formed in the case of the moderately dried styrene. G values for the initiating radical and ion formation are calculated to be, independently of the dose rate and water content, 0.66 and 0.027, respectively. It was suggested that oligomer was formed in the early stage by the interaction of cation with anion and only those cations which had survived underwent polymerization.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 2683-2693 
    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 kinetic equation was derived for the radiation-induced polymerization of styrene under the assumption that both radical and cationic polymerizations take place concurrently throughout the whole range of the dose rate of radiation and the water content of the styrene. The equation enables one to calculate rates of the total, radical, and cationic polymerization at a given dose rate and water content and agrees satisfactorily with experimental results, which cover dose rates from 4.2 × 10 to 2.1 × 105 rad/sec and water contents from 3.2 × 10-3 to 3.5 × 10-2 mol/l. Experimental estimation of the contribution of radical and cationic mechanisms was done by GPC curves of polymers obtained under various conditions. When the contribution of ionic mechanism is expressed in weight percent, it changes from 0% to 100% in the range of the experiment; on the other hand, if it is expressed in mole percent, it is independent of the dose rate and remains constant throughout the whole range of the experiment.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 239-262 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The infrared absorption spectra of selected crystalline and noncrystalline bands were studied in bulk-crystallized specimens of linear polyethylene which encompassed the extremely wide density range of 0.92-0.99 g./cm.3. The analysis of the data obtained at room temperature yield degrees of crystallinity by infrared methods which are in very good accord with the values deduced from the density measurements. Studies of the infrared spectra as a function of temperature give fusion curves which are in agreement with those obtained by thermodynamic methods. However, in order to obtain these latter results cognizance must be taken of the large negative temperature coefficient of the specific extinction coefficients of the crystalline bands from room temperature to the melting point. The necessary data to account for this phenomena were obtained from studies of the spectra of the n-paraffin, C94H190, where molecular crystals are formed. Analysis of the two gauche bands, at 1352 and 1303 cm.-1, which are assigned to the noncrystalline regions demonstrate that for bulk-crystallized samples of lowest densities the intensity ratio at room temperature is identical to that expected from the pure melt at this temperature. The conclusion is thus reached that the noncrystalline regions in these cases and the pure melt are structurally very similar. For samples of higher density, where the crystallite size is comparable to the extended chain length, the intensity ratio of the two gauche bands is altered. This change could reflect a change in the sequential distribution of gauche bonds. This intensity ratio for crystals formed from dilute solution is very similar to that for the high-density bulk-crystallized material and indicates a similarity in structure of the noncrystalline regions in the two cases.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 48 (1993), S. 1825-1829 
    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: Surface graft polymerization of a hydrophobic monomer, 2,2,3,3,3-pentafluoropropyl methacrylate (5FMA), onto hydrophilic poly(vinyl alcohol) (PVA) and cellulose films was studied after corona discharge of the films. It was found that grafting strongly depended on the reaction medium; especially, addition of alcohol to the monomer greatly accelerated graft polymerization. For instance, when an ethanol/ water /5FMA mixture (65/25/10, by volume) was used as the polymerization medium. the PVA and cellulose films corona-discharged for a few minutes exhibited a high contact angle up to 100° after 30 min polymerization, the graft density being approximately 170 μg/cm2 for cellulose and 80 μg/cm2 for PVA. © 1993 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 4 (1966), S. 1043-1048 
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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