Permeation and sorption of water vapour in varnish films

Abstract

An experimental investigation on the moisture permeability and sorption of detached varnish and polystyrene films is described. Details for preparation of samples and methods of test, under various conditions of vapour pressure and temperature, are given. Both the permeability and sorption of the films have been determined at constant moisture concentrations, that is, by using streams of moist air, the amounts permeating and the amounts sorbed being directly weighed. In addition to moisture permeability, some measurements of that of hydrogen and carbon dioxide are reported.