MASS-TRANSPORT IN FINITE BATHS - EFFECT OF SURFACE BARRIERS

Mass transfer of diffusants to the surface of solid polymeric material from some external medium can occur through a diffusional boundary layer. Equations exist that permit the description of such mass-transfer phenomena, but such equations are valid only for infinite bath systems, i.e., systems in which the concentration of diffusant in the external medium is constant. A new technique is given that permits the mathematical description of mass transfer through a diffusional boundary layer for finite bath systems, i.e., systems in which the concentration of diffusant in the external medium changes during the sorption process.