Synthesis and characterization of a microporous 6FDA-polyimide made from a novel carbocyclic pseudo Tröger's base diamine: Effect of bicyclic bridge on gas transport properties
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KAUST DepartmentAdvanced Membranes and Porous Materials Research Center
Chemical and Biological Engineering Program
Physical Sciences and Engineering (PSE) Division
Imaging and Characterization Core Lab
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AbstractA newly designed carbocyclic pseudo Tröger's base diamine (CTB) monomer, 2,8-dimethyl-3,9-diamino-5,6,11,12-tetrahydro-5,11-methanodibenzo[a,e]annulene (CTBDA) and its isomeric analogue 2,8-dimethyl-(1,7)(4,10)(3,9)-diamino-5,6,11,12-tetrahydro-5,11-methanodibenzo[a,e]annulene (iCTBDA), were designed for the synthesis of microporous 6FDA-based polyimides (6FDA-CTBDA and 6FDA-iCTBDA). Both polyimides were soluble, exhibited excellent thermal stability of ∼490 °C, and had high surface areas of 587 m2 g−1 (6FDA-CTBDA) and 562 m2 g−1 (6FDA-iCTBDA). A 6FDA-based polyimide derived from 4,10-dimethyl-3,9-diamino-6H,12H-5,11-methanodibenzo[b,f][1,5]-diazocine (6FDA-TBDA) was made for comparison to investigate the effects of the basic tertiary nitrogen functionality in the Tröger's base diamine on the polymer properties relative to the carbocyclic 6FDA-CTBDA analogue. 6FDA-TBDA displayed lower gas permeabilities but moderately higher gas-pair permselectivities than 6FDA-CTBDA. The enhanced permselectivity of 6FDA-TBDA resulted exclusively from higher diffusion-based selectivity. Direct gas sorption measurements demonstrated that the basicity in the Tröger's base bridge moiety enhanced the sorption capacity of CO2 only slightly and had no effect on the CO2/CH4 solubility selectivity in 6FDA-TBDA vs. 6FDA-CTBDA.
CitationAbdulhamid MA, Ma X, Miao X, Pinnau I (2017) Synthesis and characterization of a microporous 6FDA-polyimide made from a novel carbocyclic pseudo Tröger’s base diamine: Effect of bicyclic bridge on gas transport properties. Polymer 130: 182–190. Available: http://dx.doi.org/10.1016/j.polymer.2017.10.017.
SponsorsThis work was supported by funding from King Abdullah University of Science and Technology (KAUST).