화학공학소재연구정보센터
Journal of the Korean Industrial and Engineering Chemistry, Vol.18, No.5, 483-489, October, 2007
Polyaniline/Polyimide 혼합막의 기체 분리 특성
Gas Separation Properties of Polyaniline/Polyimide Blend Membranes
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초록
Polyaniline (PANI)/Polyimide (PI) 혼합막을 제조하여 PANI 함량과 doping처리가 막의 구조적 특성과 기체 분리 특성에 미치는 영향을 연구하였다. NMP를 용매로 하여 6FDA와 ODA를 반응시켜 얻어진 polyamic acid (PAA) 용액과 PANI 용액을 혼합하여 PANI/PI 혼합막을 얻었다. 얻어진 PANI/PI 막을 1M의 HCl 수용액에서 24시간 doping처리하여 doped PANI/PI 혼합막을 제조하였다. 제조한 막은 FT-IR과 XRD 및 TGA에 의하여 구조적 특성을 분석하였고, 30 ℃와 5 atm에서 압력변화법으로 H2, O2, CO2, N2 및 CH4에 대한 기체 투과 특성을 조사하였다. PANI/PI 혼합막은 PANI와 PI의 흡수특성을 잘 보여주었고 PANI보다 열적 안정성이 향상되었으며, PANI의 함량이 증가할수록 d-spacing은 감소하였다. PANI/PI 혼합막에서 기체의 투과도계수는 PANI의 함량이 증가함에 따라 감소하였으며 투과도 계수의 크기는 H2 > O2 > CO2 > N2 > CH4의 순서였다. PANI/PI막을 doping처리하면 투과도계수는 감소하나 투과선택도는 향상되었다. 특히 doping한 PANI/PI (75/25)막에서 H2/CH4의 선택도는 991을 나타내었다.
Polyaniline (PANI)/Polyimide (PI) membranes were prepared and the effects of PANI contents and doping on the structural properties and gas separation properties were studied. The polyamic acid (PAA) solution was prepared by the polycondensation reaction of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 4,4'-oxydianiline (ODA) in 1-methyl-2-pyrrolydinone (NMP) solvent. The PANI/PI blends were obtained by mixing PAA solution and PANI solution, and were doped with 1 M aqueous HCl solution for 24 h. The structural characterizations of the as-cast and doped membranes were examined by FT-IR, XRD, and TGA. The gas permeation experiments with H2, CO2, O2, N2, and CH4 were carried out by variable pressure method at 30 ℃ and 5 atm. For all gases tested, the permeability coefficients of the blends decreased with increasing PANI content and the magnitude of permeability was in the order of H2 > CO2 > O2 > N2 > CH4. The permeability for PANI/PI membranes decreased after the doping process while the permselectivity increased. For H2/CH4 separation, the doped PANI/PI (75/25) membrane has a permselectivity of 991.
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