The degradation of an aromatic polyamideimide in an NO2 atmosphere

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AbstractFilms of an aromatic polyamideimide showed a significant degradation in an NO2 atmosphere at 100 mm Hg at 50°C. The degradation was followed by the dynamic tensile measurements. In the curves of temperature dependence of dynamic loss modulus of degraded films, a separate mechanical absorption α′ peak appeared below the glass transition α peak. In the course of degradation, the α′ peak grew and shifted to lower temperature. On thermal treatment of degraded films, the α′ peak shifted to higher temperature and finally merged into the α peak. The formation of reacted surface layers by the diffusion of NO2 was confirmed by scraping off and by solvent extraction. Infrared spectroscopy showed that most amide linkages were destroyed by NO2. The gel permeation chromatography of extracted products showed that the low molecular products were occluded in degraded layers. The influence of these components caused the α′ absorption in dynamic loss curves.