@article { ISI:000264434000008,
	title = {Variation in acid moiety of polybenzimidazoles: investigation of physico-chemical properties towards their applicability as proton exchange and gas separation membrane materials},
	journal = {Polymer},
	volume = {50},
	number = {6},
	year = {2009},
	month = {MAR},
	pages = {1403-1413},
	publisher = {ELSEVIER SCI LTD},
	address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND},
	abstract = {<p>A series of polybenzimidazoles (PBIs) were prepared from 3,3{\textquoteright}-diaminobenzidine (DAB) and substituted aromatic dicarboxylic acids. Effects of added polarity, bulk and isomerism in the dicarboxylic acid moiety on the properties of formed aromatic polybenzimidazoles were investigated. Solution polycondensation procedure was optimized for individual case of PBI synthesis in order to obtain inherent viscosity of \&gt;= 1 dL/g. Analysis of physical properties, water uptake, acid doping (H(3)PO(4) and H(2)SO(4)) and gas permeability was performed. All these PBIs exhibited high thermal stability, good solvent solubility and amorphous nature. The uptake of H(3)PO(4) varied from 9 to 20.1 moles per repeat unit (mol/RU), H(2)SO(4) uptake varied from 3.39 to 3.81 mol/RU, while water uptake varied from 1.8 to 3.6 mol/RU of PBI. The dibromoterephthalic acid and tert-butylisophthalic acid based PBI showed the highest H(3)PO(4) uptake in the series, while tert-butylisophthalic acid based PBI exhibited the highest water uptake. Acid uptake was correlated with swelling of the PBI matrix, while density estimation of H(3)PO(4)-doped PBI by He gas expansion method could be correlated to the physical state of PBI. 5-tert-Butylisophthalic acid and 4,4{\textquoteright}-(hexafluoroisopropylidene)bis(benzoic acid) based PBI exhibited higher H(2) and O(2) permeability than other PBIs. The ideal gas selectivity for O(2)/H(2) was considerably higher for most of the PBIs than conventional gas separation membrane materials. These analyses suggested that some of these PBIs have a potential to be used as a PEM or gas separation membrane material. (C) 2009 Elsevier Ltd. All rights reserved.</p>},
	keywords = {Gas permeability, Polybenzimidazole, Proton exchange membrane},
	issn = {0032-3861},
	doi = {10.1016/j.polymer.2009.01.043},
	author = {Kumbharkar, S. C. and Islam, Md. Nazrul and Potrekar, R. A. and Kharul, Ulhas K.}
}
@article {45347,
	title = {Modelling of water-to-gas hollow fiber membrane humidifier},
	journal = {Chemical Engineering Science },
	volume = {192},
	year = {2018},
	month = {DEC},
	pages = {955-971},
	type = {Journal Article},
	abstract = {<p>A microscopic mathematical model is developed for membrane based water-to-gas humidification by rigorously accounting for phase equilibrium between the membrane and water phases as well as membrane and gas phases in addition to the coupled heat and mass transfer occurring across the membrane. The model is then integrated along the length of a hollow fiber membrane humidifier in order to predict humidifier performance as a function of design variables, operating variables and operational strategies. For realistic values of membrane thickness and flow parameters, the model suggests that while membrane-gas interfacial resistance alone is crucial for heat transfer, the vapor transfer is governed by the combined resistances of diffusion within the membrane and membrane-gas interface. The model is validated against experimental data obtained using a commercial hollow fiber</p>},
	keywords = {Coupled Heat and Mass, Fuel Cell Applications, Humidification, Phase equilibrium, Proton exchange membrane, Water-to-gas},
	doi = {10.1016/j.ces.2018.08.015},
	author = {Pandey, R. and Lele, A.}
}
