Effect of relative humidity on the external area of paper

Abstract

Adsorption isotherms of n-decane and mesitylene on cotton cellulose paper conditioned at several relative humidities were measured using a gas-chromatographic technique. Relative humidities in the chromatographic column were achieved by controlling the partial pressure of water in the carrier gas. From the isotherms, the external area of the paper was determined while the paper was in dynamic equilibrium with the water vapour. Between 0 and 65% relative humidity the external surface area of the paper decreased irreversibly due to some stress relaxation effects, while over 85% relative humidity the area decreased reversibly due to pore-filling by water of the large external pore system of the fibres and of the paper.