Polymer drying. IX. Effect of history on the kinetics of evaporation from poly(styrene‐co‐divinylbenzene)–liquid systems in the rubbery and glassy states

Abstract

AbstractIn these time studies of evaporation from liquid‐saturated microporous composite film samples, comprised of poly(styrene‐co‐divinylbenezene) particles enmeshed in poly(tetrafluoroethylene) microfibers, the samples were preswelled to saturation in a good solvent, such as toluene, which was then replaced via solvent exchange in excess test liquid before the start of the time study that monitored the residual weight (Wt) of sorbed liquid to virtual dryness. The patterns of change with time (i.e., Wt. vs. t and Log Wt vs. t) obtained thereby were compared with the corresponding time studies already reported for evaporation from equivalent polystyrene–liquid (PS–L) systems that did not have a history of preswelling in a better solvent. These comparisons show that the history of the samples in its liquid‐saturated gel state can affect markedly the kinetics of desorption from the PS–L system in its glassy state, and also during the interval of transition from the rubbery state to the glassy state, as discussed in the text. © 1994 John Wiley & Sons, Inc.