本研究係以聚醯胺酸(polyamic acid, PAA)為前驅物，以旋轉塗佈成膜於多孔性氧化鋁基材上，並經環化形成聚醯亞胺(polyimide, PI)後，再以熱裂化法製備碳分子篩/氧化鋁複合膜(CMS/Al2O3)，以供氣體透過之用。文中針對所合成之PI膜進行特性分析，並探討不同裂化溫度對所得碳分子篩膜特性與其氣體透過之影響。
　　
　　關於PAA之製備，係以純化後之BTDA與ODA在低溫氮氣環境下合成。經FTIR與EA分析顯示此法所得之PAA可成功製備出PI膜。TGA分析結果顯示，在氮氣氣氛下，此PI膜自500℃才開始有重量損耗，至800℃時損耗約達40％，並形成一穩定碳膜，此膜之碳含量約為 86.72％，且表面均勻、緻密性佳。XRD分析顯示各裂化溫度所得之碳膜皆為非晶態。

　　由N2與CO2於碳膜上之吸附實驗可知，兩氣體之吸附行為符合Langmuir恆溫吸附模式。碳膜之BET比表面積值約為200～500 m2/g，且隨裂化溫度增加而增大，其平均孔徑則由18.6 Å(600℃)減至7.9 Å(900℃)。另由CO2之吸附來分析碳膜微孔結構結果。700℃裂化之CMS具有最大之微孔洞體積。但當裂化溫度達到900℃時，由於孔洞之收縮，導致CO2亦難以進入，故吸附量下降，由此估計孔徑應與CO2之動力學直徑(3.3 Å)相當或更小。

　　以碳分子篩膜進行氣體透過實驗，結果顯示當裂化溫度為600℃時，由於碳膜孔洞過大，氣體透過機制主要受Knudsen diffusion控制，其N2及CO2之透過速率隨透過溫度之增加而下降，不具分子篩之分離能力；裂化溫度在700℃以上所得之碳膜，由於微孔收縮，故呈現分子篩特性，但其氣體透過量亦減小。當透過溫度增加時，由於活化擴散(activated diffusion)機制，氣體透過量隨之增加。裂化溫度為700℃所得碳分子篩/氧化鋁複合膜具有最佳之CO2/N2分離能力，在50℃、500 kPa條件下，CO2、N2之透過係數分別為0.25×10-10 mole/m2 sec Pa、3.0×10-10 mole/m2 sec Pa，其分離係數高達12。

　　In this study, the carbon molecular sieve/alumina (CMS/Al2O3) composite membranes were prepared from the polyamic acid (PAA)-derived polyimide (PI) /Al2O3 membranes by pyrolysis. The properties of CMS membranes as well as the PI membranes were characterized by FT-IR, EA, TGA, SEM and AFM techniques. Moreover, the effects of pyrolysis temperature on characteristics of CMS composite membranes and the permeations of N2 and CO2 were also investigated.

　　Firstly, the PAA synthesized from BTDA and ODA at 0oC under N2 atmosphere was successfully used to obtain the PI. The result of TGA showed that the PI was thermally stable below 500 oC at N2 atmosphere. Up to 800 oC, a stable carbon membrane was achieved with weight loss of about 40 % and carbon content of 86.72 %, which was amorphous structure from XRD analysis.

　　From the results of gas adsorption experiments, it was found that the adsorptions of N2 and CO2 on CMS membranes follow the Langmuir model. The BET surface area of CMS membrane, estimated about 200~500 m2/g based on the N2 adsorption at 77 K, was increased with increasing the pyrolysis temperature, whereas the average pore size decreased from 18.6 Å (600 oC) to 7.9 Å (900 oC). From the result of CO2 adsorption at 273 K, it revealed that the CMS membrane pyrolyzed at 700 oC exhibited the largest total volume of micropores. However, as the pyrolysis temperature increased to 900℃, the adsorption amount of CO2 was dramatically decreased due to the shrinkage of micropores. Accordingly, it was inferred that the pore diameter was approximate to or less than the kinetic diameter of CO2 (3.3 Å).

　　From the result of gas permeation experiments, it showed that permeabilities of N2 and CO2 in the CMS membrane pyrolyzed at 600 oC were decreased with increasing the permeating temperature, indicating that the gas permeation rate was dominantly controlled by Knudsen diffusion and was without molecular sieving effect. For the CMS membranes pyrolyzed at temperature above 700 oC, due to the shrinkage of pore, the gas permeability was decreased with increasing pyrolysis temperature. However, due to the activated diffusion effect, the gas permeability was increased with elevating the permeating temperature.

　　In addition, it showed that the CMS membrane pyrolyzed at 700 oC exhibited the best separation efficiency for CO2/N2 among all. This result was in accordance with those obtained from gas adsorption. At permeation conditions of 50 oC and 500 kPa, the CO2 and N2 permeabilities were 3.0×10-10, and 0.25×10-10 mole/m2 sec Pa, respectively, with the high CO2/N2 selectivity of 12.

1. P. Meares, ed., Membrane Separation Processes, Elsevier, Amsterdam, p. 259 (1976).

2. M. A. Anderson, M. J. Gieselmann and Q. Xu, “Tatiana and Alumina Ceramic Membranes.” Journal of Membrane Science, 39, 243 (1988).

3. S. L. Matson, J. Lopez and J. A. Quinn, “The Pinch Design Method for Heat Exchanger Networks.”, Chemical Engineering Science, 38(4), 503 (1983).

4. S. L. Michaels, “Crossflow Microfilters Ins and Outs.”, Chem. Eng., 96, 84 (1989, Jan.).

5. 仲川勤編, 最新分離機能膜, CMS, 日本東京 (1987)。

6. H. P. Hsieh, “AMERICAN INSTITUTE OF CHEMICAL ENGINEERS.”, AlChE Symp. Ser., 34(1), 116 (1988).

7. R. J. R. Uhlhorn, K. Keizer and A. J. Burggraaf, “Gas and surface diffusion in modified g alumina systems.”, Journal of Membrane Science, 46, 225 (1989).

8. R. R. Bhave, Inorganic Membrane: Synthesis, Characteristics and Applications, Van Nostrand Reinhold, New York (1991).

9. J. D. Way and D. L. Roberts, “Hollow Fiber Inorganic Membranes for Gas Separations.”, Separation Science and Technology, 27, 29 (1992).

10. A. B. Shelekhin, A. G. Dixon and Y. H. Ma, “Adsorption, permeation, and diffusion of gases in microporous membranes. I. Adsorption of gases on microporous glass membranes.”, Journal of Membrane Science, 75, 221 (1992).

11. Y. Cao, B. Liu and J. Deng, “Catalytic
dehydrogenation of ethanol in Pd–M/γ-Al2O3 composite membrane reactors.”, Applied Catalysis A: Genera, 154, 129 (1997).

12. 曾怡享, 碳分子篩膜之製備及其特性之研究, 國立成功大學碩士論文 (1999)。

13. 朱秦億, 鈀及鈀銀複合膜之製備、特性分析及其氫/氮選透性之研究, 國立成功大學博士論文 (2004)。

14. W. J. Koros, R. T. Chern, Handbook of Separation Process Technology, John Willy & Son, New York (1987).

15. H. Suda and K. Haraya, “Propylene-propane separation using a carbon molecular sieve membrane.”, Journal of Physical Chemistry B, 100, 3988 (1997).

16. R. A. Alberty and R. J. Silbey, Physical Chemistry, 2nd Edition. John Willy & Son, New York (1998).

17. 陳見財, 分離膜污染阻塞與控制簡介, 環保產業雙月刊第11期。

18. M. A. de la Casa-Lillo, J. Alcaniz-Monge, E. Raymundo-Pinero, D. Cazorla-Amoros and A. Linares-Solano, “Molecular sieve properties of general-purpose carbon
fibres.”, Carbon, 36(9), 1353 (1998).

19. Y. Yin and R. E. Collins, “Carbon Molecular-
Sieve Films Produced by DC Sputtering”, Carbon, 31(8), 1333 (1993).

20. V. Jayaraman, Y.S. Lin, M. Pakala, and R.Y. Lin, “Fabrication of Ultrathin Metallic Membranes on Ceramic Support by Sputter Deposition.”, J. Membrane Sci., 99, 89 (1995).

21. Do, D.D., Hu, X. and Rao, G.N., “Experimental Determination of the Intrinsic Surface Diffusivity of Hydrocarbons in Activated Carbon by Means of a Differential Analysis.”, Separation Technology (ed. E.F. Vansant), Elsevier, 309 (1994).

22. 黃盟欽, PI-TEOS複合高分子之製備及其特性分析, 國立成功大學化程實驗(2002)。

23. K. Wang, H. Suda, K. Haraya, “The characterization of CO2 permeation in a CMSM derived from polyimide.”, Separation and Purification Technology, 31, 61 (2003).

24. C. Nguyen, D.D. Do, K. Haraya , K. Wang, ”The structural characterization of carbon molecular sieve membrane (CMSM) via gas adsorption.”, Journal of Membrane Science, 220, 177 (2003).

25. A.B. Fuertes and T.A. Centeno, Journal of Membrane Science, 144, 105 (1998).

26. Teresa A. Centeno, Antonio B. Fuertes, Carbon,
38, 1067 (2000)

27. T.A. Centeno, A.B. Fuertes, Letters to the editor / Carbon, 41, 2016 (2002).

28. T.A. Centeno, J.L. Vilas, A.B. Fuertes, Journal of Membrane Science, 228, 45 (2004).

29. A.B. Fuertes, T.A. Centeno, Microporous and Mesoporous Materials, 26, 23 (1998).

30. Antonio B. Fuertes, Carbon, 39, 697 (2001).

31. A.B. Fuertes, D.M. Nevskaia, T.A. Centeno, Microporous and Mesoporous Materials, 33, 115 (1999).

32. T.A. Centeno, A.B. Fuertes, “Carbon molecular sieve membranes derived from a phenolic resin supported on porous ceramic tubes.”, Separation and Purification
Technology, 25, 379 (2001).

33. De Q. Vu, William J. Koros , Stephen J. Miller, “Mixed matrix membranes using carbon molecular sieves I Preparation and experimental results.”, Journal of Membrane Science, 211, 311 (2003).

34. De Q. Vu, William J. Koros , Stephen J. Miller, “Mixed matrix membranes using carbon molecular sieves II Modeling permeation behavior.”, Journal of Membrane Science, 211, 335 (2003).

35. De Q. Vu, William J. Koros, Stephen J. Miller, “Effect of condensable impurity in CO2/CH4 gas feeds on performance of mixed matrix membranes using carbon molecular sieves.”, Journal of Membrane Science, 221, 233 (2003).

36. Keisha M. Steel , William J. Koros, “Investigation of porosity of carbon materials and related effects on gas separation properties.”, Carbon, 41, 253 (2003).

37. Michael S. Strano, Henry C. Foley, “Temperature- and pressure-dependent transient analysis of single component permeation through nanoporous carbon membranes.”, Carbon, 40, 1029 (2002).

38. Michael S. Strano, Henry C. Foley, “Modeling ideal selectivity variation in nanoporous membranes.”, Chemical Engineering Science, 58, 2745 (2003).

39. J.N. Barsema, N.F.A. van der Vegt., G.H. Koops, M. Wessling, “Carbon molecular sieve membranes prepared from porous fiber precursor.”, Journal of Membrane Science, 205, 239 (2002).

40. J.N. Barsema, J. Balster, V. Jordan, N.F.A. van der Vegt, M. Wessling, “Functionalized Carbon Molecular Sieve membranes containing Ag-nanoclusters.”, Journal of Membrane Science, 219, 47 (2003).

41. Youn Kook Kim, Ho Bum Park, Young Moo Lee, “Carbon molecular sieve membranes derived from metal-substituted sulfonated polyimide and their gas separation properties.”, Journal of Membrane Science, 226, 145 (2003).

42. Ho Bum Park, Youn Kook Kim, Ji Min Lee, Sun Yong Lee, “Relationship between chemical structure of aromatic polyimides and gas permeation properties of their carbon molecular sieve membranes.”, Young Moo Lee, Journal of Membrane Science, 229, 117 (2004).

43. Youn Kook Kim, Ji Min Lee, Ho Bum Park, Young Moo Lee, “The gas separation properties of carbon molecular sieve membranes derived from polyimides having carboxylic acid groups.”, Journal of Membrane Science, 235, 139 (2004).

44. N. A. Adrova, M. I. Bessonov, L. A. Laius ans A.
P. Rudakov, Polyimide: A new class of thermally stable polymers(in Russian), Nauka, Leningrad(1968).

45. 吳宏明, 聚醯亞胺覆銅膜之製備及其裂化現象之研究, 國立功大學化工碩士論文 (1996)。

46. 施俊安, 可溶性聚醯亞胺之合成及物性之研究, 國立成功大學化工碩士論文 (1996)。

47. 蔡東穎, 可溶性聚醯亞胺之研究, 國立成功大學化工碩士論文(1998)。

48. 李政義, 含羥基可溶性聚醯亞胺之合成及性質研究, 國立成功大學化工碩士論文(2001)。

49. 蘇盟雄, 含第三丁基可溶性聚醯胺-醯亞胺之合成及性質研究, 國立成功大學化工碩士論文(2002)。

50. 張武君, 含苯氧基聚醯亞胺之合成及性質研究, 國立成功大學化工碩士論文(2002)。

51. A. Weill and E. Dechenaux, “Some observations on the static hold up of aqueous solutions”, Polym. Eng. Sci., 28, 945 (1988).

52. D. Bornside, C. Macosko, L. Scriven, “On the Modeling of Spin Coating.”, Journal of Imaging Technology, 13, 122 (1987).

53. B. D. Washo, “AUTOMATIC SIGNATURE VERIFICATION BASED ON ACCELEROMETRY.”, IBM J. Res. Dev., 21, 190 (1977).

54. B. T. Chen, “Structural transformations of aromatic polyamides containing carborane at increased temperatures.”, Polym. Eng. Sci., 23, 399 (1983).

55. 賴耿陽, 碳材料化學與工學, 初版, 復漢初版社 (1991)。

56. K. Kinoshita, Carbon, Electrochemical and physicochemical properties, John Wiley & Sons (1988).

57. 李秉傑, 邱宏明, 王奕凱, 非均勻系催化原理與應用, 初版, 渤海堂文化公司(1988)。

58. J. W. Patrick, Porosity in Carbons, 1st ed., Edward Arnold (1995).

59. D. S. Scott, F. A. Dullien, “Diffusion of Ideal Gases in Capillaries and Porous Solids.”, AlChe J., 8, 113 (1962).

60. K. Keizer, R. J. R. Uhlorn, V. T. Zaspalis, A. J. Burggraaf, “Microporous sol-gel modified membranes for hydrogen separation.”, Key Eng. Mater., 61, 143 (1991).

61. K. Keizer, R. J. R. Uhlorn, R. J. Van Vuren, A. J. Burggraaf, “Gas separation mechanisms in microporous modified Ag/Al2O3 membranes.”, Journal of Membrane Science, 39, 285 (1988).

62. 陳慧英, “氧化鋁薄膜之製備及其在氣體分離上之應
用”, 國立成功大學化學工程研究所博士論文(1995)。

63. G. L. Holleck, “Diffusion and solubility of
hydrogen in palladium and palladium silver alloys.”, J Chem. Phys., 74, 503 (1970).

64. Y. Hishiyama, K. Inagaki, I. Kanaoka, H. Fujii, T. Koidesawa, Y. Shimazawa and A. Yoshida, “Graphitization behavior of kapton-derived carbon film related to structure, microtexture and transport properties.”, Carbon, 35(5), 657 (1997).

65. H. Konno, T. Nakahashi and M. Inagaki, “State analysis of nitrogen in carbon film derived from polyimide kapton.”, Carbon, 35(5), 669 (1997).

66. M. Takahashi and M. Fuji, “Synthesis and Fabrication of Inorganic Porous Materials: From Nanometer to Millimeter Sizes”, KONA, 20, 84(2002).