Effects of casting and post casting annealing on xylene isomer transport properties of Torlon® 4000T films
Type
ArticleDate
2010-07Permanent link to this record
http://hdl.handle.net/10754/598071
Metadata
Show full item recordAbstract
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.Citation
Chafin R, Lee JS, Koros WJ (2010) Effects of casting and post casting annealing on xylene isomer transport properties of Torlon® 4000T films. Polymer 51: 3462–3471. Available: http://dx.doi.org/10.1016/j.polymer.2010.05.028.Sponsors
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.Publisher
Elsevier BVJournal
Polymerae974a485f413a2113503eed53cd6c53
10.1016/j.polymer.2010.05.028