질산증기에 의한 石油系 等方性 핏치纖維의 安定化

다국어 초록 (Multilingual Abstract)

Stabilization of pitch fiber is an important process in the production of pitch-based carbon fiber, and usually performed by an oxidat1on in hot air.
In this study, isotropic pitch fibers were stabilized by nitric acid vapor instead of hot air as an oxidant to reduce the stabilization time and temperature, and then the stabilized fibers were carbonized at 10000℃ for 30 minutes with a heating rate of 10℃/min.
The stabilized and pre-carbor11zed fibers were analyzed by the e1ernental analyzer and FT-IR. The cross-sectional structures of the carbonized fibers were observed by polarized-light microscope, and the tensile strength of them was measured.
The following results have been obtained through the experimental and analysis.
1. In the stabilization of the isotropic pitch fiber by nitric acid vapor, dealkyl oxidation and dehydrogenative nitration reactions take place, resulting in formation of surface functional groups such as carboxyl (-COOH) and nitro (-NO_2) groups.
2. The ratios of the introduced functional groups (-NO_2/-COOH) in the fibers stabilized by nitric acid vapor were decreased as the Increase of stabilization time, and all the values of the ratio were larger than 1.0. It indicates that the formation rate of the nitro groups is faster and the reactivity sites in pitch molecules to introduce the nitro groups are more than the carboxyl groups.
3. In the pre-carbonization process, all components in the fibers stabilized by hot air have been re leased gradually over 300℃, but the behaviors in the fibers stabilized by nitric acid vapor shown that weight loss have been begun below 200℃ and nitro, carboxyl and alkyl groups have been re leased stepwise.
4. The isotropic pitch fibers with about 15㎛ in diameter were completely stabilized by nitric acid vapor within 20 minutes at 85℃. In comparison with hot air stailizat1on, stabilization by nitric acid vapor became to shorten the stabilization time to 1/10 and to lower the stabilization temperature about 200℃, on the other hand, the tensile strength of the resulted carbon fiber was 10% less.

목차 (Table of Contents)

• 목차
• I. 서론 = 1
• II. 이론적 고찰 = 5
• 2-1. 핏치의 화학적구조 = 5
• 2-2. 산소와 핏치섬유의 반응성 및 기구 = 6
• 2-3. 핏치섬유의 안정화공정 개선 방향 = 10
• 2-4. 핏치와 질산의 반응 = 13
• 2-5. 산화섬유의 탄화 = 15
• III. 실험장치 및 방법 = 19
• 3-1. 실험재료 = 19
• 3-2. 실험장치 및 방법 = 20
• 3-2-1. 질산증기에 의한 산화 = 20
• 3-2-2. 공기에 의한 산화 = 22
• 3-2-3. 산화섬유의 탄화 = 22
• 3-3. 분석 = 25
• 3-3-1. 무게 측정 = 25
• 3-3-2. 원소 분석 = 25
• 3-3-3. FT-IR 분석 = 26
• 3-3-4. 편광현미경 관찰 = 26
• 3-3-5. 인장강도 측정 = 27
• IV. 결과 및 고찰 = 29
• 4-1. 안정화 = 29
• 4-1-1. 필치섬유의 무게 변화 = 29
• 4-1-2. 산화섬유의 성분 = 33
• 4-1-3. FT-IR 분석 = 37
• 4-2. 탄화 = 42
• 4-2-1. 초기탄화 = 42
• 4-2-2. 탄소섬유의 단면조직 = 51
• 4-2-3. 탄소섬유의 인장강도 = 53
• V. 결론 = 57
• 참고문헌 = 58
• 영문요약 = 63