Polybenzimidazole based random copolymers containing hexafluoroisopropylidene functional groups for gas separations at elevated temperatures

POLYMER

卷:119

Article

Singh, Rajinder P.¹  Li, Xin²  Dudeck, Kevin W.¹  Benicewicz, Brian C.²  Berchtold, Kathryn A.¹ 

[1] Los Alamos Natl Lab, Mat Phys & Applicat Div, Carbon Capture & Separat Energy Applicat CaSEA La, Los Alamos, NM 87545 USA

[2] Univ South Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA

关键词: Polybenzimidazole;    Random copolymer;    Pre-combustion;    Carbon capture;    Synthesis gas;    Hydrogen selective membrane;   

DOI  :  10.1016/j.polymer.2017.04.075

来源: Elsevier

【 摘 要 】

Polybenzimidazoles (PBIs) are attractive membrane materials for H-2/CO2 separation at hydrocarbon fuel derived synthesis gas operating conditions due to their exceptional physicochemical stability and promising permselectivity character. PBI molecular structure modification is a viable approach to disrupt chain packing altering the free-volume architecture which results in improved gas transport characteristics. This work is focused on the synthesis and characterization of novel PBI random copolymers for application as elevated temperature H-2/CO2 membranes. The co-polymerization route is expected to result in tailorable permeability and selectivity by combining the high H-2 permeability aspect of the highly disrupted loosely packed hexafluoroisopropylidene diphenyl group containing PBI segments (6F-PBI) with the highly selective tightly packed phenylene group containing PBI segments (m-PBI). 6F/m-PBI copolymers with varying 6F-PBI and m-PBI ratios having high inherent viscosity were synthesized. The structure and ratio of the 6F- and m-PBI fractions were confirmed using FTIR and NMR spectroscopic techniques. The measured gas transport properties of copolymer thin films cast in controlled environment were measured as a function of the operating conditions. The H-2 permeability increased while H-2/CO2 selectivity decreased as the 6F-PBI copolymer fraction was increased. (C) 2017 Elsevier Ltd. All rights reserved.

【 授权许可】

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