Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Transport Properties of CO2 and CH4 using Poly(ether-block-amide)/GPTMS Hybird Membranes

Poly(ether-block-amide)/GPTMS 하이브리드 분리막을 이용한 이산화탄소와 메탄의 투과특성

  • Lee, Keun Chul (Department of Chemical Engineering, Kyonggi University) ;
  • Kim, Hyunjoon (Department of Chemical Engineering, Kyonggi University)
  • 이근철 (경기대학교 화학공학과) ;
  • 김현준 (경기대학교 화학공학과)
  • Received : 2016.06.30
  • Accepted : 2016.08.03
  • Published : 2016.10.01
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Abstract

Poly(ether-block-amide)(PEBAX$_{(R)}$) resin is a thermoplastic elastomer combining linear chains of hard-rigid polyamide block interspaced soft-flexible polyether block. It was believed that the hard polyamide block provides the mechanical strength and permselectivity, whereas gas transport occurs primarily through the soft polyether block. The objective of this work was to investigate the gas permeation properties of carbon dioxide and methane for PEBAX$^{(R)}$-1657 membrane, and compare with those obtained for other grade of pure PEBAX$^{(R)}$, PEBAX$^{(R)}$-2533 and PEBAX$^{(R)}$ based hybrid membranes. The hybrid membranes based PEBAX$^{(R)}$ were obtained by a sol-gel process using GPTMS ((3-glycidoxypropyl) trimethoxysilane) as the only inorganic precursor. Molecular structure and morphology of membrane were analyzed by $^{29}Si$-NMR, DSC and SEM. PEBAX$_{(R)}$-2533 membrane exhibited higher gas permeability coefficients than PEBAX$^{(R)}$-1657 membrane. This was explained by the increase of chain mobility. In contrast, ideal separation factor of $CO_2/CH_4$ for PEBAX$^{(R)}$-1657 membrane was higher than PEBAX$^{(R)}$-2533 membrane. It was explained by the decrease of diffusion selectivity caused by increase of chain mobility. For PEBAX$^{(R)}$/GPTMS hybrid membrane, gas permeability coefficients were decreased with reaction time. Gas permeability coefficient of $CH_4$ was more significantly decreased than $CO_2$. It can be explained by the reduction of chain mobility caused by the sol-gel process, and strong affinity of PEO segment with $CO_2$. Comparing with pure PEBAX$^{(R)}$-1657 membrane, ideal separation factor of $CO_2/CH_4$ for PEBAX$^{(R)}$/GPTMS hybrid membrane has decreased to 4.5%, and gas permeability coefficient of $CO_2$ has increased 3.5 times.

Poly(ether-block-amide)(PEBAX$^{(R)}$)는 열가소성 탄성체(thermoplastic elastomer, TCU)로서 hard-rigid amide block과 soft-flexible ether block으로 구성되어 있으며, 분자량과 두 block간의 구성비에 따라 여러 종류가 있다. PEBAX$^{(R)}$는 분리막소재로 이용할 경우 PEBAX$^{(R)}$의 hard amide block은 우수한 기계적 특성과 선택도를, 그리고 soft ether block은 높은 투과도를 제공할 수 있다. 따라서 본 연구에서는 2종류의 PEBAX$^{(R)}$를 사용하여 기체 분리막을 제조하고, 종류에 따른 이산화탄소와 메탄의 투과특성 변화를 연구하였다. 또한 순수 PEBAX$^{(R)}$ 분리막의 투과특성을 향상시키기 위해 GPTMS ((3-glycidoxypropyl)trimethoxysilane)를 무기전구체로 사용한 PEBAX$^{(R)}$/silica 하이브리드 분리막을 제조하여 이산화탄소와 메탄의 투과특성을 측정하였으며, 29Si-NMR, DSC, SEM 분석을 통해 무기전구체의 도입에 따른 고분자의 구조 변화를 연구하였다. 순수 PEBAX$^{(R)}$-1657과 PEBAX$^{(R)}$-2533 분리막의 투과도 측정 결과, 상대적으로 높은 ether block 비율의 PEBAX$^{(R)}$-2533 분리막의 투과도 계수가 높은 값을 가졌다. 상대적으로 높은 ether block 함량 때문에 고분자 사슬의 유연성이 보다 크기 때문으로 볼 수 있고, 이로 인한 확산선택도의 감소 효과에 의해 이상분리인자는 PEBAX$^{(R)}$-1657 분리막이 보다 높은 값을 가졌다. PEBAX$^{(R)}$/GPTMS 하이브리드 분리막의 기체투과도 측정 결과 $CO_2$와 $CH_4$ 모두 반응시간이 경과됨에 따라 $CO_2$에 비해 $CH_4$의 투과도 계수가 낮아졌으나 이상분리인자는 증가함을 보였다. GPTMS가 가수분해되어 생성된 silanol이 고분자 사슬에 침투되어 축합과정을 거치며 공유결합에 의해 사슬간 결합이 커지고 사슬의 운동성을 감소시켜 투과도 계수가 낮아진 것으로 보이며, PEO segment와 $CO_2$와의 강한 친화도에 의해 $CO_2$의 투과도계수가 상대적으로 덜 낮아진 것으로 판단된다. 순수 PEBAX$^{(R)}$-1657 순수 분리막의 결과와 비교하였을 때 이상분리인자는 4.5% 감소한 반면 $CO_2$ 투과도계수는 3.5배 증가하는 우수한 결과를 보였다.

Keywords

References

  1. Li, D. and Hwang, S. T., "Gas Separation by Silicon Based Inorganic Membrane at High Temperature," J. Membr. Sci., 66, 119-127(1992). https://doi.org/10.1016/0376-7388(92)87002-F
  2. Shelekhin, A. B., Grosgogeat, E. J. and Hwang, S. T., "Gas Separation Properties of a New Polymer/Inorganic Composite Membrane," J. Membr. Sci., 66, 129-141(1992). https://doi.org/10.1016/0376-7388(92)87003-G
  3. Sforca, M. L., Yoshida, I. V. P. and Nunes, S. P., "Organic-Inorganic Membranes Prepared from Polyether Diamine and Epoxy Silane," J. Membr. Sci., 159, 197-207(1999). https://doi.org/10.1016/S0376-7388(99)00059-9
  4. Chung, T., Jiang, L. Y., Lia, Y. and Kulprathipanja, S., "Mixed Matrix Membranes (MMMs) Comprising Organic Polymers with Dispersed Inorganic Fillers for Gas Separation," Prog. Polym. Sci., 329(4), 483-507(2007).
  5. Iwata, M., Adachi, T., Tomidokoro, M., Ohta, M. and Kobayashi, T., "Hybrid Sol-Gel Membranes of Polyacrylonitrile-Tetraethoxysilane Composites for Gas Permselectivity," J. Appl. Polym. Sci., 88(7), 1752-1759(2003). https://doi.org/10.1002/app.11895
  6. Que, W., Zhang, Q. Y., Chan, Y. C. and Kam, C. H., "Sol-gel Derived Hard Optical Coatings via Organic/Inorganic Composites," Composites Sci. Technol., 63, 347-351(2003). https://doi.org/10.1016/S0266-3538(02)00227-0
  7. Sridhar, S., Suryamurali, R., Smitha, B. and Aminabhavi, T. M., "Development of Crosslinked Poly(ether-block-amide) Membrane for $CO_2$/$CH_4$ Separation," Colloids and Surfaces A., 297, 267-274(2007). https://doi.org/10.1016/j.colsurfa.2006.10.054
  8. Bondar, V. I., Freeman, B. D. and Pinnau, I., "Gas Transport Properties of Poly(ether-b-amide) Segmented Block Copolymers," J. Polym. Sci.(Part B: Polym. Phys.), 38(15), 2051-2062(2000). https://doi.org/10.1002/1099-0488(20000801)38:15<2051::AID-POLB100>3.0.CO;2-D
  9. Car, A., Stropnik, C., Yave, W. and Peinemann, K., "Pebax$^{(R)}$/Polyethylene Glycol Blend Thin Film Composite Membranes for $CO_2$ Separation: Performance with Mixed Gases," Separation and Purification Technol., 62(1), 110-117(2008). https://doi.org/10.1016/j.seppur.2008.01.001
  10. Kim, H., Lim, C. and Hong, S., "Gas Permeation Properties of Organic-Inorganic Hybrid Membranes Prepared from Hydroxyl-Terminated Polyether and 3-isocyanatopropyltriethoxysilane," J. Sol-Gel Sci. Technol, 36(2), 213-221(2005). https://doi.org/10.1007/s10971-005-3782-y
  11. Kim, J. H., Ha, S. Y. and Lee, Y. M., "Gas Permeation of Poly(amide-6-b-ethylene oxide) Copolymer," J. Membr. Sci., 190(2), 179-193 (2001). https://doi.org/10.1016/S0376-7388(01)00444-6
  12. Kim, H., "Gas Permeation Properties of carbon Dioxide and Methane for PEBAX$^{TM}$/TEOS Hybrid Membranes," Korean Chem. Eng. Res., 49(4), 460-464(2011). https://doi.org/10.9713/kcer.2011.49.4.460
  13. Brinker, C. J., "Hydrolysis and Condensation of Silicates: Effects on Structure," Journal of Non-Crystalline Solids, 100, 31-50(1988). https://doi.org/10.1016/0022-3093(88)90005-1
  14. Miller, R. L., "Crystallographic Data and Melting Points for Various Polymers," in: Brandrup, J., Immergut, E. H., Grulke, E. A., Abe, A., Bloch D. R., (Eds.), Polymer Handbook, 4th ed., John Wiley & Sons, New Jersey, NJ(1999).
  15. Mehta, R. H., "Physical Constants of Various Polyamides," in: Brandrup, J., Immergut, E. H., Grulke, E. A., Abe, A., Bloch D. R., (Eds.), Polymer Handbook, 4th ed., John Wiley & Sons, New Jersey, NJ(1999).
  16. Kim, S. W., "Oxygen Permeation Characteristics of Nano-Silica Hybrid Thin Films," J. Korean Oil Chemists' Soc., 24(2), 174-181 (2007).
  17. Kim, J. H. and Lee, Y. M., "Gas Permeation Properties of Poly(amide-6-b-ethylene oxide)-Silica Hybrid Membranes," J. Membr. Sci., 193(2), 209-225(2001). https://doi.org/10.1016/S0376-7388(01)00514-2
  18. Shchipunov, Y. A. and Karpenko, T. Y., "Hybrid Polysaccharide-Silica Nano-composites Prepared by the Sol-Gel Technique," Langmuir : the ACS Journal of Surfaces and Colloids, 20(10), 3882-3887(2004). https://doi.org/10.1021/la0356912
  19. Lin, H. and Freeman B. D., "Gas Solubility, Diffusivity and Permeability in Poly(ethylene oxide)," J. Membr. Sci., 239(1), 105-117(2004). https://doi.org/10.1016/j.memsci.2003.08.031
  20. Lim, C., Hong, S. and Kim, H., "Effect of Polyether Diamine on Gas Permeation Properties of Organic-Inorganic Hybrid Membranes," J. Sol-Gel Sci. Technol, 43, 35-40(2007). https://doi.org/10.1007/s10971-007-1553-7