Characterization of Membrane Compaction

Peterson et al. (1998) also used UTDR to show that the compressive strain for integral cellulose-acetate membranes has both elastic and inelastic components, only some of which are recoverable that is, membranes display some degree of nonrecoverable compressive strain when subjected to high pressures. UTDR also revealed that the recovery of these membranes is viscoelastic or time dependent, which possibly explains the hysteresis effects observed when membranes are subjected to pressure cycling. 

MEMBRANE CHARACTERIZATION BY ULTRASONIC TIME-DOMAIN REFLECTOMETRY 

Interestingly, after the transmembrane pressure is reduced to zero, a permanent strain of approximately 6% is observed at a recovery time of 150 min. These studies also indicated that membrane compaction increases with an increasing concentration of CO2 in the feed stream. The ability to characterize membrane mechanical response to CO2 is of particular interest owing to the plasticizing namre of this gas. 

---