The process and mechanism of the photodegradation of Polyphenylene-ether [poly (oxy-1-4 (2, 6-dimethyl phenylene)) PPE] have been studied with a Xenon arc lamp and a monochromatic light source in the National Institute for Basic Biology at Okazaki, Japan. The absorption peak at 280nm of irradiated film increased with increasing the irradiation time. However, when irradiated film was dissolved in chloroform, this absorption peak deacreased as the irradiation time increased. This suggested that the absorption peak at 280nm was due to the crossslinking structure of the side chain. On the other hand, the absorption peak at 340nm, increased by irradiation of monochromatic light at 300nm wavelength, that indicated the formation of a quinone-methide. In the case of the photodegradation of PPE, the experimental results in the irradiation with polychromatic and monochromatic sources showed that the shorter wavelength caused the decomposition and crosslinking of the PPE side chain, but the coloring was produced by the relatively longer wavelength light.

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In order to examine the geographical effect on the weatherability, plasticized polyvinyl chloride films were exposed at the six sites, Iwamizawa, Choshi, Tsukuba, Ritto, Shin-Nanyo, and Miyakojima. The exposed sample surfaces were characterized by scanning electron microscope, surface roughness, and FT-IR. The sample surfaces degraded more severely in Ritto, Shin-Nanyo and Tsukuba than in Miyakojima where air temperature was high and quantity of solar radiation was large. Rather than the air temperature, quantity of solar radiation, or rainfall, the degradation of the plasticized polyvinylchloride correlated with SO2 and /or NOx concentration (s).

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