Abstract: Thermal Oxidizing Aging properties of modified aromatic polyoxadiazoles fiber at 200℃、250℃ and 300℃ were studied by the Thermal Oxidizing Aging method, and then its thermal properties were compared with that of m-aramid fiber and polyimide fiber. The results show that the breaking strength retention of modified aromatic polyoxadiazoles fiber after heat aging of 80 days at 200℃ is near 90%, over 60% after 65 days at 250℃, and more than 70% after 25 days at 300℃. The results also show that the linear density of modified aromatic polyoxadiazoles fiber after thermal oxidizing aging does not change obviously, which declares the excellent dimensional stability of modified aromatic polyoxadiazoles fiber.

Key words: modified aromatic polyoxadiazole fiber , m-aramid fiber , polyimide fiber , thermal oxidizing aging