CO₂超臨界 流體에서 轉化法을 利用한 폴리카보네이트와 폴리프로필렌 非對稱 多孔性 膜의 製造 및 應用 = Preparation and application of asymmetric and porous membranes with polycarbonate and polypropylene by an inversion method in supercritical CO₂fluid

다국어 초록 (Multilingual Abstract)

In this study, polycarbonate and polypropylene porous membranes were prepared with supercritical CO_(2). The effects of reaction time, temperature, and pressure of supercritical CO_(2) on the preparation of porous membranes were examined. The electrolyte composite membrane for fuel cell was obtained with the prepared porous membrane.
The results were as follows.
1. The prepared polycarbonate and polypropylene porous membranes have sponge structures. The cross sections of the membranes showed asymmetric structures and the surfaces of the membrens showed uniform pore distributions.
2. The optimum conditions of preparation of polycarbonate porous membrane, considering porosity and tensile strength, were 19 wt% of polycarbonate concentration and 8.1 wt% of polyethylene glycol concentration. The membrane showed porosity of 72∼77 % and tensile strength of 1.8 kgf/㎟.
3. Considering porosity and tensile strength, the optimum condition of preparation of polypropylene porous membrane was 10 wt% of polypropylene concentration. It showed porosity of 73∼80 % and tensile strength of 0.2 kgf/㎟.
4. The supercritical CO_(2) was used to extract the polyethylene glycol for the preparation of polycarbonate porous membrane and the optimum extraction conditions were 35 ℃, 150 bar, and 20 min.
5. The supercritical CO_(2)was employed to extract the camphene for the preparation of polypropylene porous membrane and the optimum conditions of extraction were 45 ℃, 150 bar, and 10 min.
6. In the preparation of polycarbonate and polypropylene porous membranes, the supercritical CO_(2) in extraction process worked more efficiently by 19 % and 10 % than other liquid solutions such as ultra-pure water and ethanol.
7. The optimum process for the impregnation of Nafion^(ⓡ) solution into polycarbonate porous membrane was vacuum inhalation method. The prepared polycarbonate composite membrane showed Nafion^(ⓡ) density of 0.83 g/㎤ in the polycarbonate porous membrane and water uptake of 47 %. The polycarbonate composite membrane had about ion conductivity of 0.0024 S/cm, which was 57 % of ion conductivity of Nafion 115 membrane.
8. The dip coating process was excellent for the impregnation of Nafion^(ⓡ) solution into polypropylene porous membrane. The obtained polypropylene composite membrane showed Nafion^(ⓡ) density of 1.37 g/㎤ in the polypropylene porous membrane and water uptake of 24 %. The polypropylene composite membrane had about ion conductivity of 0.0029 S/cm, which was 57 % of ion conductivity of Nafion 115 membrane.

목차 (Table of Contents)

• 목차 = i
• List of tables = iii
• List of figures = v
• 1. 서론 = 1
• 2. 이론 = 8
• 2-1. 상전화법에 의한 막제조 = 8
• 2-1-1. 건습식법 및 습식법 = 8
• 2-1-2. 열식법 = 10
• 2-2. 다공성 고분자 분리막에서의 이온전도 = 12
• 2-3. 초임계 유체의 용해도 = 15
• 3. 실험 = 19
• 3-1. 시료 = 19
• 3-2. 실험장치 = 19
• 3-3. 실험 방법 = 25
• 4. 결과 및 고찰 = 33
• 4-1. 다공성 막의 제조 및 형상 = 33
• 4-2. 공극률 = 39
• 4-3. 인장강도 = 44
• 4-4. 초임계 유체의 추출효율 = 47
• 4-4-1. 반응시간의 영향 = 47
• 4-4-2. 온도의 영향 = 54
• 4-4-3. 압력의 영향 = 60
• 4-5. 이온 전도도 = 63
• 4-5-1. 전해질 복합막의 제조 = 63
• 4-5-2. 전해질 복합막의 이온 전도도 = 65
• 5. 결론 = 67
• 참고문헌 = 69
• Appendices = 77
• Abstract = 97