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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 40 (1968), S. 1116-1118 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 32 (1960), S. 725-726 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 32 (1960), S. 1209-1210 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 37 (1965), S. 1422-1423 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 32 (1960), S. 103-106 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 1631-1639 
    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: According to mechanisms described in the literature, photodecomposition of nylon 66 proceeds through the abstraction of the hydrogen on the carbon α to the amide NH group by a free radical which has been activated by photo absorption. In the propagation phase, the α-carbon radical could readily react with atmospheric oxygen to form a hydroperoxide. The formation of a hydroperoxide in the photodecomposition scheme for nylon 66 has been detected but has not been measured quantitatively. With the colorimetric method described in this paper, it is now possible to determine the peroxide content in a polyamide to a level of 1 μmole/g. with a relative precision of less than 5%. The polyamide is dissolved in tetrafluoropropanol, to which aliquots of potassium iodide and glacial acetic solutions are added. The absorbance of the liberated iodine is measured in a 1-cm. cell at 400 mμ and the hydroperoxide concentration determined from a calibration curve constructed from hydrogen peroxide solution standards. The rate of peroxide formation, which is dependent on the wavelength of ultraviolet radiation, can be correlated to the strength loss exhibited by a nylon 66 yarn free from antioxidant and delustrant. In addition, an increase in the level of thermal degradation will accelerate yarn strength loss and peroxide formation under ultraviolet exposure. The hydroperoxide begins to decompose at about 100°C. Yarn finish will contribute to the peroxide formation during exposure.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 7 (1963), S. 1629-1634 
    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: Methods described in the literature for the estimation of the cyclic oligomer content (which includes cyclic dimer, trimer, etc.) of nylon 6 are indirect determinations, generally based on weight differences, and require the prior extraction of ∊-caprolactam (monomer) from the sample. Infrared studies show that all of the cyclic oligomers have a strong NH deformation band at 6.45 μ, whereas the monomer does not exhibit such a band. This difference in the infrared is the basis of a direct determination of the cyclic oligomer content in the presence of monomer. In the method, the residue obtained after evaporation of the water extract of nylon 6 is dissolved in tetrafluoropropanol, and the absorbance at 6.45 μ is determined by the base line method. If the per cent moisture in the original nylon 6, the per cent water extractables, and the per cent oligomers in the water extract are known, one can also estimate the monomer content of the sample.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 2117-2128 
    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: Infrared bands in the 900-1100 cm-1 region are sensitive to thermal energy. These bands can result from intermolecular coupling, producing the crystal lattice, or from intramolecular coupling of the various atomic groups in a regular helix or coiled chain. In either case an increase in temperature will disrupt the coupling mode, resulting in a form of structural relaxation and a reduction in the integrated absorbance. It is proposed that the temperature at which the peak areas begin to decrease be assigned as the Tg. This is measured by continuously scanning a selected peak in the infrared spectrum of a polymer film while it is heated at a rate of about 1°C/min. Using this technique polyamides (nos. 6,66, and 610) exhibited transitions in the 30-50°C range, and by studying the increase in the free NH region (3440 cm-1) of nylon 66 two other transitions were detected at 80 and 137°C; the latter represents a change in the nylon 66 crystal state. An amorphous film of poly(ethylene terephthalate) displayed a transition at 58-68°C (Tg) and at 85°C, which is the crystallization temperature. Films of poly(vinyl acetate) and polystyrene exhibited transitions at 25-37°C and at 70°C, respectively.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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