Abstract
In high volume liquid transfer into or out of a polymer, swelling and shrinkage phenomena occur. Simultaneously, the diffusivity for the liquid transfer is concentration dependent, increasing exponentially. An investigation into the process of diffusion–absorption and diffusion–evaporation has been carried out. Five parameters intervene: the diffusivity; its concentration dependency through the polymer; the coefficients of convective transfer at the surface during absorption; or desorption; and the extent of liquid absorbed. At the beginning of the absorption stage, the convective coefficient and the diffusivity of the liquid in the polymer free from liquid were determined. At the onset of evaporation from the pre-saturated polymer, the convective coefficient and the diffusivity in the polymer were also determined. Finally, the concentration dependency of the diffusivity was obtained from the values of the diffusivity in the polymer free from liquid and saturated. Rather good agreement is shown between the kinetics determined either experimentally or calculated using these parameters and a numerical model.
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