Diffusion in the nylon 12 and water system

Abstract

Diffusion in a nylon 12 and water system has been measured by means of a quartz microblance and weighing bottle method at penetrant concentrations ranging from about 0.2to 2 (wt%) and temperatures ranging from 20 to 70°C. The average diffusion coefficient (Formula Presented) for quenched nylon 12 film and the apparent average diffusion coefficient (Formula Presented)av* for annealed nylon 12 film as a function of penetrant concentration have been determined from the absorption—desorption data. The integral diffusion coefficient (Formula Presented)s as a function of penetrant concentration has been determined from the steady-state behavior and compared with (Formula Presented)av or (Formula Presented). The concentration dependences of (Formula Presented)av and (Formula Presented) are somewhat different from each other, but the concentration dependences of Ds for quenched film are the same as thosefor annealed film when plotted against the weight of water absorbed per unit weight of the amorphous part of the dry polymer. The solubility S and the permeability P in the nylon12+water system are proportional to the volume fraction Xa of the amorphous phase. The mutual diffusion coefficient at the limit of zero penetrant concentration for this system is compared with those for other polymer+water systems. © 1976 The Society of Polymer Science, Japan.