Phase inversion in plane membranes. I. Computer-aided gravimetric data acquisition and fitting procedures of the desolvation kinetics
✍ Scribed by C. Castellari; S. Ottani
- Publisher
- Elsevier Science
- Year
- 1988
- Tongue
- English
- Weight
- 814 KB
- Volume
- 69
- Category
- Article
- ISSN
- 0011-9164
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✦ Synopsis
Solvent evaporation from a plane cast membrane has been followed gravimetrically with the aid of a small on-line computer. The desorption experiments have been carried out dissolving poly(vinylidene) fluoride in 1,3dioxolane and cellulose acetate in acetone.
The experimental data have been fitted with the expressions usually employed both in sorption and desorption experiments and a statistical analysis has been carried out. Since the predicted values do not fit the gravimetric data beyond the gel point, a new expression is presented. This equation utilizes two adjustable constants to characterize each system and leads to a good agreement between experiment and calculation. Only in one case the best fit requires three parameters. The new equation describes the experimental data better than the commonly available predictive methods, and covers also the range beyond polymer gelation. When derived with respect to time, the predictive equation gives a good estimate of the evaporative flux. Since the prediction is valid at all times, the values of the flux can be confidently inserted into a mathematical model aimed at reproducing the drying of a polymeric solution.