posted on 2023-01-06, 20:00authored byMing Yu, Andrew B. Foster, Colin A. Scholes, Sandra E. Kentish, Peter M. Budd
Physical aging of glassy polymers leads to a decrease
in permeability
over time when they are used in membranes. This hinders the industrial
application of high free volume polymers, such as the archetypal polymer
of intrinsic microporosity PIM-1, for membrane gas separation. In
thin film composite (TFC) membranes, aging is much more rapid than
in thicker self-standing membranes, as rearrangement within the thin
active layer is relatively fast. Liquid alcohol treatment, which swells
the membrane, is often used in the laboratory to rejuvenate aged self-standing
membranes, but this is not easily applied on an industrial scale and
is not suitable to refresh TFC membranes because of the risk of membrane
delamination. In this work, it is demonstrated that a simple method
of storage in an atmosphere of methanol vapor effectively retards
physical aging of PIM-1 TFC membranes. The same method can also be
utilized to refresh aged PIM-1 TFC membranes, and one-week methanol
vapor storage is sufficient to recover most of the original CO2 permeance.