@article { ISI:000278905100015,
	title = {Investigation of gas permeation properties of systematically modified polybenzimidazoles by N-substitution},
	journal = {Journal of Membrane Science},
	volume = {357},
	number = {1-2},
	year = {2010},
	month = {JUL},
	pages = {134-142},
	publisher = {ELSEVIER SCIENCE BV},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<p>Gas permeation behavior of a series of thermally stable N-substituted polybenzimidazoles by systematically varying bulk and flexibility of the substituent was investigated. Two different PBIs having variation in their acid moiety, viz., PBI-I (based on isophthalic acid) and PBI-BuI (based on 5-tert-butyl isophthalic acid) were selected for N-substitution by alkyl groups possessing different bulk and flexibility. These substituent groups were methyl, n-butyl, methylene trimethylsilane and 4-tert-butylbenzyl. Pure gas sorption and permeability using H(2), N(2), O(2), CH(4) and CO(2) were investigated and correlated with physical properties of formed polymers. Estimation of dual-mode sorption parameters, coefficients of sorption, permeability and diffusion for different gases provided an insight towards effects of nature of a substituent group and parent PBI on governing gas sorption and permeation properties. By changing the substituent group, diffusivity coefficients was found to vary to a larger extent than the solubility coefficient. This significantly enhanced gas permeability for different gases by 1.2-129 times than that of parent PBIs. The permselectivity P(O2)/P(N2) was increased (up to 237\%), while for other gas pairs, it was decreased to a different extent. (C) 2010 Elsevier B.V. All rights reserved.</p>},
	keywords = {Diffusion, Gas permeation, N-Substitution, Polybenzimidazole, Sorption},
	issn = {0376-7388},
	doi = {10.1016/j.memsci.2010.04.014},
	author = {Kumbharkar, Santosh C. and Kharul, Ulhas K.}
}
