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Title: Blended polybenzimidazole and melamine-co-formaldehyde thermosets

Polybenzimidazole [PBI; poly-2,2’(m-phenylene)-5,5’-bibenzimidazole] is known to have excellent high temperature stability (up to 450 ºC) and superb H2/CO2 selectivity compared to most high performance (HP) polymers. But, PBI has issues in thin-film formation compared to other HP polymers, due to challenging processing techniques. In this work, new blended thermosets were made with PBI and poly(melamine co-formaldehyde) [PMF] to produce stable thin-films after thermal processing at 220-250 ºC. PBI film formation is difficult, and the film tends to fracture and fissure due to loss of processing aids and stabilizers (salt/acid additives) that are found in PBI solutions above10 wt %. The PBI-PMF blended thermosets we report do not have stabilizers, and can be made into dense thin-films. It is remarkable that these thermally processed PBI-PMF films were stable in deionized water for extended periods, whereas many PBI films that contain additives are not. The PBI-PMF films were analyzed using pure and mixed gas permeability measurement techniques. At 250 °C, the data show H2/CO2 gas selectivities greater than 13. Also, from the gas permeation data, the energy of activation (Ep) of a mixed gas stream for PBI-PMF shows that hydrogen permeates more easily than the other gases, while the permeabilities for themore » larger kinetic diameter gases are greatly diminished. The FT-IR spectra show that the PBI-PMF films have changed from parent PBI after thermal processing, and PMF dominates the spectra even in minor percent compositions. Altogether, the reported PBI-PMF thermoset films show good stability which can be used for high temperature gas separation.« less
Authors:
 [1] ;  [1] ;  [1]
  1. Idaho National Lab. (INL), Idaho Falls, ID (United States)
Publication Date:
OSTI Identifier:
1357450
Report Number(s):
INL/JOU--15-36391
Journal ID: ISSN 0376-7388; PII: S0376738816303325
Grant/Contract Number:
AC07-05ID14517
Type:
Accepted Manuscript
Journal Name:
Journal of Membrane Science
Additional Journal Information:
Journal Volume: 515; Journal Issue: C; Journal ID: ISSN 0376-7388
Publisher:
Elsevier
Research Org:
Idaho National Laboratory, Idaho Falls, ID (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE gas permeation; high performance polymers; polybenzimidazole; polymers; synthesis