Abstract
Two-types of carbon fiber, anisotropic- and isotropic- pitch based, were expose to isothermal oxidation in air and $CO_{2}$ gas and the weight change rates was measured by TGA apparatus. Thc oxidation rate was laster in air than in $CO_{2}$ gas, and the oxidation rare of isotropic T- 101s liher was over 23 9 times faster than that of anisotropic HM-60 filler at $600^{\circ}C$ in air. The activation energy was 36-56 Kcal/mole at lower temperature range and 6- 13 Kcal/molc at higher temperature range. It was higher that the transition temperalure 01 reaction zone(zone 1. 2, :i) of 11M-GO fiber than that of T-101s fiber, and it was higher in $CO_{2}$ gas than in air. From SEM observation, it Lvas found that the oxidation of carbon fibers was progressed through the imperfection.
이방성과 등방성을 갖는 두 종류의 피치계 탄소섬유를 TGA장치를 이용하여 $CO_{2}$gas와 공기중에서 등온산화반응을 실시하였다. $CO_{2}$ gas보다 공기중에서의 산화가 훨씬 빠르게 일어났으며, $600^{\circ}C$공기중에서 등방성 T-10IS섬유는 이방성 HM-60섬유보다 23.9배나 빠른 산화속도를 보였다. 실험적으로 구한 활성화에너지를 저온에서 36-56Kcal/mole의 값을 가지며, 고온에서는 6-13Kcal/mole의 값을 나타내었다. 반응기구(zone 1,2,3)의 천이도는 T-10IS섬유보다 HM-60 섬유가 높았으며, 공기중에서보다 $CO_{2}$ gas분위기에서 더 높게 나타났다. SEM으로 관찰된 표면상변화로부터 탄소섬유의 산화반응은 섬유의 결함을 따라 진행된다는 것을 알 수 있었다.
