Measurements of sorption isotherms and diffusion coefficients by means of a magnetic suspension balance

Sorption equilibrium and diffusion coefficients of solvents in a polymer were determined by use of a magnetic suspension balance (MSB). The binary systems poly(vinyl acetate)–methanol and poly(vinyl acetate)–toluene at 20, 40 and 60 °C were investigated. The solvent activity was calculated with the Flory–Huggins and UNIFAC-FV model and the diffusion coefficient with the free-volume theory. The measured values are compared with literature data and Flory–Huggins interaction parameters and free-volume parameters were adapted to the measured data.