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首页> 美国政府科技报告 >Survey of the Photodegradation of Organic Polymers Exposed to Ultraviolet Radiation.
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Survey of the Photodegradation of Organic Polymers Exposed to Ultraviolet Radiation.

机译：紫外辐射有机聚合物光降解的研究进展。

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Some of the variables involved in the photodegradation of organic polymers are examined, with special emphasis given to research on the photochemistry of poly(vinyl chloride). New approaches to the problem of protecting polymers from ultraviolet (u.v.) radiation in extraterrestrial space are required to replace present hit-and-miss procedures for selecting u.v. inhibitors. Attention will be focused on those variables that are critical to the successful u.v. stabilization of polymers. The discussion will center about the nature of the u.v. absorbing grouping, the wavelength dependence of the photochemical reaction and the rate enhancing effect of polychromatic radiation. The absorption spectra of the u.v. absorbing groups - present in PVC film has been measured by means of single-beam spectrophotometry. These groups are identified as polyenes on the basis of comparison with known polyenes and the wavelength dependence curve of color development. The interaction of the pi-electrons of the polyenes initially present in PVC with antimony trichloride markedly retarded the rate of photodegradation. Useful criteria are presented for the choice of energy-transfer systems for the u.v. protection of PVC. Monochromatic quantum yields of photolysis for a variety of linear polymers are compared. These quantum yields appear to fall into two classes; those accompanied by chain scission, and those accompanied by crosslinking. p1.

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