Effects of casting and post casting annealing on xylene isomer transport properties of Torlon® 4000T films

Raymond Chafin, Jong Suk Lee, William J. Koros

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Procedures for Torlon® 4000T membrane formation were developed to provide attractive and repeatable xylene separation properties. Torlon® 4000T membrane films cast by our method were investigated in terms of thermally induced imidization, molecular weight enhancement, and solvent removal. After development of the Torlon® 4000T casting procedure, pervaporation of a xylene mixture (i.e. 30% para-xylene, 30% meta-xylene, 30% ortho-xylene, and 10% ethylbenzene) was performed in both Torlon® 4000T and post casting annealed Torlon® 4000T films. The xylene pervaporation in annealed Torlon® 4000T film at 200°C gave a permeability of 0.25 Barrer and a selectivity of 3.1 (para/ortho) and 2.1 (para/meta) respectively. A so-called " permeability collapse" reflecting an accelerated reduction in the free volume is consistent with significant temperature-induced changes in the films observed after thermal annealing at 300°C. This conditioning effect is induced by a combination of heat treatment and the presence of the interacting aromatic penetrants. Optical methods were used to verify that the density of annealed samples exposed to xylene for 5 days eventually increased, suggesting that the membrane is originally swollen upon initial xylene exposure, and then relaxes to a more densified, and more discriminating state. © 2010 Elsevier Ltd.
Original languageEnglish (US)
Pages (from-to)3462-3471
Number of pages10
JournalPolymer
Volume51
Issue number15
DOIs
StatePublished - Jul 2010
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors would like to acknowledge financial support from BP, The Coca Cola Company, and Award No. KUS-I1-011-21 made by King Abdullah University of Science and Technology (KAUST). Also, we would like to convey special thanks to Chuck Hoppin for his assistance in making the viscometry measurements.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

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