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  • 1
    Electronic Resource
    Electronic Resource
    Fluoride-promoted, dye-sensitized photooxidation of enols (1982)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 104 (1982), S. 4695-4696 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00381a040
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis, characterization, and stability of poly(3,4-dibutoxythiophenevinylene) copolymers (1993)
    s.l. : American Chemical Society
    Macromolecules 26 (1993), S. 2704-2710 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00063a011
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Photodegradation of UV absorbers: Kinetics and structural effectsPaper presented at the “16th International Conference on Advances in the Stabilization and Degradation of Polymers” in Luzern (Switzerland), June 14-17, 1994. (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 232 (1995), S. 229-238 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When poly(methyl methacrylate) films containing UV absorbers are exposed to UV light, the absorbers undergo photodegradation resulting in loss of absorbance. If the data extend for less than one half-life, both zero and first order kinetic treatment give fairly linear fits, but the rate constants so derived are dependent on the initial absorbance of the films. When the zero order rate constants are corrected to account for the higher rate of degradation near the surface compared with the bulk that occurs in highly absorbing films, consistent “infinite absorption” zero order rate constants are derived. The inhomogeneous degradation is due to only the highly absorbed, higher energy light contributing significantly to the degradation. For the benzophenone and benzotriazole classes of absorber, at least 65% of the degradation is due to light with wavelengths 〈 350 nm. Structural variations generally caused only small differences in the rates of degradation of these classes of absorbers unless the substitutions disrupted the intramolecular hydrogen bonds that are critical for stability. If the hydrogen bond is weakened, the absorber is less stable.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1995.052320114
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of accelerated exposure conditions on the photodegradation of BPA polycarbonate/ABS blends (1997)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 247 (1997), S. 1-18 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A BPA polycarbonate/ABS blend containing 2% TiO2 was exposed to xenon are irradiation under SAE J 1885 conditions (quartz/borosilicate filters). “CRD” conditions (borosilicate/borosilicate filters), and ASTM D4459-86 conditions (borosilicate/soda lime filters). The results are consistent with the conclusion that polycarbonate dominates the photochemistry of polycarbonate/ABS blends under SAE J1885 and CRD xenon are exposure conditions. Exposure under ASTM D4459-86 conditions produced results similar to CRD conditions with some additional contribution attributable to the ABS component. The “activation spectrum” of PC/ABS blends under CRD conditions closely resembled the sum of the activation spectra of ABS and PC determined under similar conditions. The well-known change in mechanism that occurs when polycarbonate is exposed to light with wavelengths 〈 300 nm was manifested by increased rates of yellowing, surface erosion. and loss of gloss under SAE J 1885 conditions. Because of the mechanism change, testing under quartz/borosilicate filtered xenon are exposure cannot be considered to be appropriate for polycarbonate-containing formulations.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1997.052470101
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  • 5
    Electronic Resource
    Electronic Resource
    Calculation of the efficiency of ultraviolet screeners in plastics (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 33 (1987), S. 525-531 
    Details
    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: Calculation of the effect of light absorbers (UV screeners) on the photochemistry of polymers shows that a critical factor in reducing the rate of photodegradation is the thickness of the actual degraded layer. When the degradation is confined to a zone within a few microns of the exposed surface, the efficiency of light absorption as a stabilization mechanism is greatly reduced. The relative absorptivity of the base resin and pigment loadings are calculated to have a minor effect on stabilization efficiency for polymers having thin layers of degradation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070330220
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  • 6
    Electronic Resource
    Electronic Resource
    Calculated and measured outdoor UV doses (1997)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 252 (1997), S. 217-236 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The ultraviolet (UV) radiation dose received by a sample is often the determining factor in its outdoor weathering lifetime. However, little relevant data exist for UV doses except for certain standard locations and orientations such as for the commercial test sites in Florida and Arizona. We have modified a computer program by Jokela based on other atmospheric radiation models in the literature to calculate UV doses for any latitude and orientation relative to standard exposure in Florida and have used the fraction of sunshine data for various sites that are readily available from meteorlogical compendia to correct for cloudiness. The usefulness of the calculations have been substantiated by examining the amount of yellowing in unstabilized polycarbonate films exposed at several orientations at six sites in the northern hemisphere. The calculations and doses inferred from the yellowing data are in generally good agreement, although there is increased error in highly cloudy regions and for the northerly exposures.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1997.052520115
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    Paper (German National Licenses)
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