New insights into structural evolution in carbon molecular sieve membranes during pyrolysis

被引:128
作者
Adams, Jason S. [1 ]
Itta, Arun K. [1 ]
Zhang, Chen [1 ]
Wenz, Graham B. [1 ]
Sanyal, Oishi [1 ]
Koros, William J. [1 ]
机构
[1] Georgia Inst Technol, Sch Chem & Biomol Engn, 311 Ferst Dr, Atlanta, GA 30332 USA
关键词
GAS-TRANSPORT PROPERTIES; TEMPERATURE-DEPENDENCE; SEPARATION; POLYIMIDES; PERMEABILITY; PERFORMANCE; MECHANISM; GRAPHENE;
D O I
10.1016/j.carbon.2018.09.039
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Carbon molecular sieve (CMS) membranes separate penetrants using size and shape-selective pores. In this paper we report pyrolysis of a 6FDA:BPDA-DAM polyimide precursor between 500 and 800 degrees C and measure gas evolution during the CMS structural development. The CMS materials were then characterized using combined transport properties, porosimetry, FTIR, Raman spectroscopy, TGA-FTIR, WARD, and elemental analysis measurements to assess their resulting physical and chemical properties. The results support a previous vision that fragmentation of the polyimide precursor occurs to form aromatic strands that provide building blocks for the overall CMS cell structure. This fact notwithstanding, these new findings indicate that constituent strands appear to be more complicated than previously suggested. An ordering process of such strands can generate a bimodal morphology comprising larger micropores with irregular cell walls containing ultramicropores. Permeability and permselectivity of the CMS for the C2H4/C2H6 pair are also correlated with CMS structures based on the above characterizations. The results of this work suggest that molecular probe-based transport measurements are by far the most useful tools to study these complex, amorphous materials for molecular separation applications. (C) 2018 Elsevier Ltd. All rights reserved.
引用
收藏
页码:238 / 246
页数:9
相关论文
共 45 条
[1]   Pore morphology and temperature dependence of gas transport properties of silica membranes derived from oxidative thermolysis of polydimethylsiloxane [J].
Adams, Jason ;
Bighane, Neha ;
Koros, William J. .
JOURNAL OF MEMBRANE SCIENCE, 2017, 524 :585-595
[2]   From molecular mechanochemistry to stress-responsive materials [J].
Black, Ashley L. ;
Lenhardt, Jeremy M. ;
Craig, Stephen L. .
JOURNAL OF MATERIALS CHEMISTRY, 2011, 21 (06) :1655-1663
[3]   POLYIMIDES AS PRECURSORS FOR ARTIFICIAL CARBON [J].
BURGER, A ;
FITZER, E ;
HEYM, M ;
TERWIESCH, B .
CARBON, 1975, 13 (03) :149-157
[4]   Iron-containing carbon molecular sieve membranes for advanced olefin/paraffin separations [J].
Chu, Yu-Han ;
Yancey, David ;
Xu, Liren ;
Martinez, Marcos ;
Brayden, Mark ;
Koros, William .
JOURNAL OF MEMBRANE SCIENCE, 2018, 548 :609-620
[5]   Gas-Transport-Property Performance of Hybrid Carbon Molecular Sieve-Polymer Materials [J].
Das, Mita ;
Perry, John D. ;
Koros, William J. .
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 2010, 49 (19) :9310-9321
[6]   Defect characterization in graphene and carbon nanotubes using Raman spectroscopy [J].
Dresselhaus, M. S. ;
Jorio, A. ;
Souza Filho, A. G. ;
Saito, R. .
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 2010, 368 (1932) :5355-5377
[7]  
Ehlers G.F.L., 1970, J. Polym. Sci., V8, P3511
[8]  
FLORY PJ, 1984, ADV POLYM SCI, V59, P1
[9]   Basis of permeability/selectivity tradeoff relations in polymeric gas separation membranes [J].
Freeman, BD .
MACROMOLECULES, 1999, 32 (02) :375-380
[10]   Temperature dependence of gas transport and sorption in carbon molecular sieve membranes derived from four 6FDA based polyimides: Entropic selectivity evaluation [J].
Fu, Shilu ;
Sanders, Edgar S. ;
Kulkarni, Sudhir S. ;
Wenz, Graham B. ;
Koros, William J. .
CARBON, 2015, 95 :995-1006