Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
637018 | Journal of Membrane Science | 2009 | 14 Pages |
Abstract
The establishment of specific concentration profiles inside the LDPE membrane during permeation and sorption experiments evoke time-dependent structure changes of the LDPE matrix and such chain reorganisations consequently influence the transport parameters and they are also related to a certain form of high concentration-evoked molecular aggregation (clustering). X-Ray diffraction measurements excluded that the observed phenomena could be due to significant irreversible changes in the crystallinity of the material. Toluene and heptane favourably influence one another's transport and consequently both sorption and permeation experiments reveal a distinct coupling effect. Permeation experiments show a gradual increase of the integral diffusion with increasing vapour activity whereas VPC and gravimetric sorption analysis find a maximum around activity a = 0.7. This difference is due to the deviation from Fickian behaviour at high activity and to fundamental differences in the measurement principle.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Filtration and Separation
Authors
Karel Friess, Johannes Carolus Jansen, OndÅej VopiÄka, Alena Randová, VladimÃr Hynek, Milan Å Ãpek, Lidmila Bartovská, Pavel Izák, Maarten Dingemans, Jo Dewulf, Herman Van Langenhove, Enrico Drioli,