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Key Features of Polyimide‐Derived Carbon Molecular Sieves
Author(s) -
Qiu Wulin,
Leisen Johannes E.,
Liu Zhongyun,
Quan Wenying,
Koros William J.
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202106740
Subject(s) - molecular sieve , pyromellitic dianhydride , polyimide , raman spectroscopy , fourier transform infrared spectroscopy , carbon fibers , chemical engineering , pyrolysis , carbon 13 nmr , gas separation , materials science , characterization (materials science) , chemistry , membrane , polymer chemistry , organic chemistry , nanotechnology , catalysis , physics , composite material , biochemistry , layer (electronics) , composite number , optics , engineering
Abstract Carbon molecular sieve (CMS) membranes have impressive separation properties; however, both chemical and morphology structures need to be understood better. Here we characterize CMS with the simplest polyimide (PI) PMDA/pPDA (PMDA=pyromellitic dianhydride, pPDA= p ‐phenylenediamine), using FTIR, solid‐state 15 N‐NMR and 13 C‐NMR, XPS, XRD, and Raman spectra to study chemical structure. We also compare gas separation properties for this CMS to a CMS derived from a more conventional PI precursor. The detailed characterization shows the presence of aromatic pyridinic, pyrrolic rings as well as graphitic, pyridonic components and a few other groups in both CMS types derived from the very different precursors. The CMS morphologies, while related to precursor and pyrolysis temperature details, show similarities consistent with a physical picture comprising distributed molecular sieving plate‐like structures. These results assist in understanding diverse CMS membrane separation performance.