| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1988: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1987: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Hindered amine light stabilizers (HALS) have recently been utilized as light stabilizers in plastics in largest amount. However there remain many unobvious points on the action mechanism. It was found in the last year that hals were able to form phenolic substrates from quinones. In this fiscal year, the formation of phenolic substrates will be studied in more detail, and the action mechanism will be discussed.
1) Formation of phenols from quinones: The formation of phenolic substrates from quinones was found to be much enhanced by UV irradiation and/or addition of an adequate amount of a hydroperoxide.
2) Isolation and identification of phenols: The formation of phenolic substrates by interaction of HALS with quinones was ascwetained by electrochemical methods. Furthermore, in the autoxidation system containing both HALS and quinones, phenols were detected qualitatively by a Prussian Bule test, and were isolated and identified by a chromatographic method and FT-IR, respectively.
3) Action mechanism: Hals were not concerned with light stabilization directly. On the contrary, quinones derived from antioxidant phenols were easily excited by UV light to induced the degradation of plastics. In the case that HALS exist together with quinones, quinones excited by absorption of harmful UV light are reduced by HALS, resulting in the regeneration of some antioxidant phenols. Consequently, light stabilization will be attained.
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