Modeling and Comparison with Experiment for Solvent Squeezing from Polymer Gels

We have compared the experimental results on solvent squeeze from cylindrical poly(vinyl alcohol) (PVA) gels with the model presented in this paper. The model says that a characteristic time for solvent squeeze, which is also a retardation time of the creep of gels, is proportional to the diameter squared. A simplified version of the model, which is valid when the creep strain is small enough, indicates that retardation time is independent of the applied stress and the height of gels approaches to a constant value in a single-exponential manner. Experiments on PVA gels say that the change in height occurs almost in a single-exponential manner. The retardation time was independent of the applied stress at small stresses but became longer in the high stress region, as in the case of the presented model. The diameter dependence of the retardation time for the PVA gels was weaker than the model prediction. As a whole, the simplified version of the model is useful to explain the squeezing behavior of the PVA gels.