Ozone interaction with conjugated polymers—II. Polyphenylacetylene |
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Authors: | Franco Cataldo |
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Institution: | Progega s.n.c., via Casilina 1626/A, 00133, Rome, Italy |
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Abstract: | Free-standing films of cis-transoidal polyphenylacetylene, when treated with ozonized air at 1–2% by weight O3 concentration, undergo a cis-trans isomerization induced by ozone as shown by electronic spectra. Moreover, the presence of the radical cation of polyphenylacetylene can be observed during ozone addition. The cis-trans isomerization is also confirmed by FT-IR spectra of polyphenylacetylene ozonized in solution. Hydroperoxidic groups, as well as peroxidic and aldehydic, are observed by FT-IR spectroscopy on ozonized polyphenylacetylene; in addition, ozonide groups are clearly present. The kinetics of ozonization of cis-transoid and trans-cisoid polyphenylacetylene was followed by electronic spectroscopy. The curves obtained as a function of ozonization time have a characteristic sigmoid shape. Polyphenylacetylene reacts more slowly with ozone than with the isolated double bonds of cis-1,4-polyisoprene, and thus it cannot act as an antiozonant. |
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