Temperature effects during the sorption and desorption of water vapor in high polymers. I. Fibers with particular reference to wool

Abstract

Abstract The sorption‐desorption method of measuring diffusion constants for water in polymers is often complicated by the accompanying heat effects. This is particularly true in the case of wool and other protein fibers because of the large heats of sorption. Corrections for this effect have been reported by CASSIE et al. assuming that the water vapor was taken up to equilibrium essentially instantaneously. Simple experiments have demonstrated that the diffusivity must also be taken into account and the correction equations have been modified to include the rate of diffusion. The necessary parameters have been determined experimentally for wool fabric and the extent of the corrections demonstrated. The correction factors increase with increasing water content and rapidly become several hundred percent. At very high water contents the correction parameters become so large that the equations become too sensitive for accurate corrections to be made. Measurements of untreated and styrene grafted wool have been made, the diffusivity of water is less in the grafted wool and is also less affected by the concentrations in keeping with its more hydrophobic nature.