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Degradation of partially mononitrated-poly(N-vinylcarbazole) by thermogravimetry

✍ Scribed by F. Zamora; M.C. Gonzalez; L.M. Leon

Publisher: Elsevier Science
Year: 1990
Tongue: English
Weight: 328 KB
Volume: 26
Category: Article
ISSN: 0014-3057
DOI: 10.1016/0014-3057(90)90047-8

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✦ Synopsis

Fractions of cationic poly(N-vinylcarbazole) (PNVC-A) and unfractionated radical poly(Nvinylcarbazole) (PNVC-B) have been nitrated in dimethylsulphoxide using a sulphuric-nitric acid mixture. Proportions of 3-nitrocarbazoyl units, ranging from 70 to 90% were found in PNVC-A samples depending on the molecular weight. An i.r.-band at 650 cm-i present in dinitrated carbozoyl compounds but absent from mononitrated, could be used for analysis of polymer mixtures or copolymers, containing those units. By differential scanning calorimetry, exothermal and endothermal processes were observed. An average value ofAH = 272 + 8 J/g in samples A and AH = 218 + 8 J/g in samples B were found for the exothermal process. This process corresponds with the first stage observed by thermogravimetry in degradation. Samples with nitration degree <76% did not show that behaviour. The activation energy during degradation depended on both molecular weight and nitration degree.

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