| Popis: |
A mathematical model is derived for computer simulation of solvent removal from thin polymer films on a moving web for the polyvinylacetate-acetone and polymethylacrylate- ethyl acetate systems. The model uses the Crank-Nicholson 6 point implicit numerical method solved by the substitution method, to solve the coupled, non-linear, partial differen- tial equations for mass and energy transport in the film. Concentration and temperature dependence of diffusion in polymer-solvent systems is handled by using an exponential Arrehnius type diffusion coefficient. Interphase transport is accounted for by exact solution of the boundary layer equations for high rate of mass transfer. The study investigates the effect of carrier gas velocity, pressure, solvent content, and temperature upon solvent removal rate. |
