乾燥時のPVA偏析に関する数学的シミュレーション

抄録

For quantitative analysis of surface segregation of PVA, a one-dimensional drying model for PVA-water-alumina was taken, and transfer of PVA in the drying process was mathematically simulated based on drying rate of slurry and diffusion coefficient of PVA. The results of simulation agreed well with the measured results. The surface segregation of PVA was found to result from the migration to the surface caused by a capillary force and the back-diffusion driven by the concentration gradient. In the simulation, forming of a gelated region of PVA was considered during the constant rate drying period at higher drying temperatures. The gelated region is the reason to reduce the drying period in this system. Adsorption of PVA on the particle surface appeared to affect the surface segregation of PVA in the cases of lower drying temperatures and lower concentrations of PVA.