BINARY ADSORPTION EQUILIBRIA OF VOLATILE HUMECTANT AND WATER-VAPOR FOR TOBACCO-LEAVES

To reveal a fundamental function of a volatile humectant such as propy lene glycol, binary adsorption equilibria of propylene glycol and wate r vapors for tobacco leaves were examined with a flow-type multi-compo nent adsorption system. Surface tensions were measured for aqueous sol ution of propylene glycol. The adsorbed amount of the propylene glycol as well as water increased with an increase in the vapor pressure of propylene glycol, under the constant conditions of temperature and vap or pressure of water. The surface tension for aqueous solution of prop ylene glycol was greater than that of ethanol. Therefore, propylene gl ycol was found to have a function of increasing the equilibrium moistu re content of the tobacco leaves, causing the more capillary condensat ion.