@article { ISI:000251722700028, title = {Assessing feasibility of polyarylate-clay nanocomposites towards improvement of gas selectivity}, journal = {Journal of Membrane Science}, volume = {306}, number = {1-2}, year = {2007}, month = {DEC}, pages = {277-286}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Polymer-clay nanocomposites are well known to reduce the penetrant permeability by following tortuous path. Effects of such reduction in gas permeability on variation in selectivity of nanocomposites prepared using a high permeability polymer were examined. The polyarylate: poly (tetramethyl bisphenolA-iso/terephthalate) that exhibits high permeability and moderate selectivity was chosen for making nanocomposites with two organically modified clays (Cloisite 6A and 10A) by solution intercalation method. The nanocomposite formation for various clay loadings (3, 5 and 7\% w/w) in polyarylate was ascertained by change in physical properties (X-ray diffraction, DMA, TEM). Behavior of solution viscosity and nanocomposite density indicated existence of polymer-clay layer interactions. As anticipated, though the gas permeability of pure gases, viz., He, N-2, CH4 and CO2 exhibited decrease, it was not monotonous. This decrease was more for larger gases (N-2, CH4 and CO2) in comparison to the decrease for smaller gas (He) permeability. This led to a decrease in CO2/N-2 and CO2/CH4 selectivities and increase in He/CO2 selectivity; while He/CH4 selectivity was increased substantially at 7\% clay loading. This variation indicated feasibility of nanocomposites formation as a tool for improving selectivity of certain gas pairs. (c) 2007 Elsevier B.V. All rights reserved.

}, keywords = {Gas permeation, Nanocomposites, polyarylates, selectivity, solution intercalation}, issn = {0376-7388}, doi = {10.1016/j.memsci.2007.09.001}, author = {Bhole, Yogesh S. and Wanjale, Santosh D. and Kharul, Ulhas K. and Jog, Jyoti Prakash} } @article { ISI:000250122000026, title = {Gas sorption and transport in polyarylates: effect of substituent symmetry and polarity}, journal = {Journal of Membrane Science}, volume = {303}, number = {1-2}, year = {2007}, month = {OCT}, pages = {244-251}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The gas sorption properties of polyarylates based on bisphenol-A possessing symmetric/asymmetric substitution by nonpolar -CH3 group and symmetrically linked terephthalic acid were examined. The effects of substitution of polar bromine on terephalic acid moiety of polyarylate based on asymmetrically substituted bisphenol were also studied for physical, sorption and transport properties. The estimation of dual mode sorption parameters, solubility and diffusion coefficient revealed that nature of the substituent and substitution type plays a crucial role in depicting permeation properties. An asymmetric substitution by -CH3 group increased solubility coefficient of pure gases (N-2, O-2, CH4 and CO2) up to 27\% and symmetric substitution increased the same up to 106\%. This was coupled with 7-35\% increase in solubility selectivity in both cases of substitution, which ascertained the usefulness of methyl group substitution in polyarylates based on terephalic acid. The pressure dependency of solubility coefficients and solubility selectivity was also investigated for these polyarylates. The sorption and transport properties of these polyarylates correlated well with physical properties of polyarylates and gases studied. The sorption/desorption kinetics of symmetrically substituted TMBisA-T was performed in order to deduce time dependent sorption behavior and to evaluate diffusivity coefficient. The apparent diffusion coefficients from sorption kinetics, desorption kinetics and from steady-states permeation-sorption were compared. The diffusion coefficients of CH4 and N-2 deduced by these methods correlated well with each other. (C) 2007 Elsevier B.V. All rights reserved.

}, keywords = {Diffusion, kinetics, permeation, polyarylates, Sorption}, issn = {0376-7388}, doi = {10.1016/j.memsci.2007.07.018}, author = {Karadkar, Prasad B. and Kharul, Ulhas K. and Bhole, Yogesh S. and Badhe, Yogesh P. and Tambe, Sanjeev S. and Kulkarni, Bhaskar D.} } @article { ISI:000274348100003, title = {Polyarylate based thin film composite (TFC) membranes: effects of coating parameters, gutter layer, and intrinsic material properties}, journal = {Separation Science and Technology}, volume = {45}, number = {2}, year = {2010}, month = {JAN}, pages = {163-171}, publisher = {TAYLOR \& FRANCIS INC}, address = {325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA}, abstract = {

Investigations in thin film composite (TFC) membrane formation with polyacrylonitrile ultrafiltration membrane as a support and three polyarylates with sequentially increased polarity are reported. Effects of TFC membrane preparation parameters viz., concentration of the coating solution, dip time, presence of solvent in pores of UF membrane support, and presence of the gutter layer were examined towards the formation of the selective skin layer, which was assessed by gas permeation analysis. TFC membranes prepared using dimethyl bisphenol-A based polyarylate exhibited similar to 3 orders of magnitude higher permeability and comparable selectivity as that of its dense membrane.

}, keywords = {Gas permeation, gutter layer, polarity, polyarylates, TFC membrane}, issn = {0149-6395}, doi = {10.1080/01496390903423089}, author = {Chendake, Yogesh J. and Bhole, Yogesh S. and Lohokare, Harshada R. and Kharul, Ulhas K.} }