Polymer drying, 11: Desorption studies using poly-(Styrene-co-divinylbenzene) samples that had been swelled to saturation in chloromethanes

The kinetics of evaporation from samples of poly(Styrene-co-divinylbenzene) presaturated with CH3Cl, CH2Cl2, CHCl3, and CCl4 were monitored to virtual dryness in order to establish how the molecular structure of the probe molecule and the conditions of evaporation affect the time-dependent pattern of transition from the rubbery to a glassy state, and the corresponding distribution of residual probe molecules entrapped in the macrostructure of the glassy state at the completion of this transition. The complexity of the relationships, before and after attaining the rigidity of the glassy state, were found to increase with the number of chlorine atoms in the probe molecule. The physical conditions during evaporation-induced transition affect both relationships in the same manner. This parallelism supports the point of view that there is a cause-and-effect relationship between the events that occur during the transition interval and the macrostructure of the resulting glassy state; the latter affects the physical properties of the product and the ensuing time-dependent aging effects. The relevance of these results to physically crosslinked polystyrene-liquid systems is discussed. One may infer that it should be possible to tailor the physical properties of glassy polymers, obtained via casting or extrusion of polymer solutions, by appropriate selection of the solvent and conditions during evaporation-induced transition to the glassy state.