The Effect of Water Activity and Penetrant Vapor Activity On the Permeation of Toluene Vapor Through a Two-Side Pvdc Coated Opaque Oriented Polypropylene Film

The permeance of toluene vapor through an oriented polypro pylene film coated with a copolymer of vinylidene chloride (PVDC) was evalu ated as a function of water activity and penetrant vapor concentration. It was found that the value of permeance increased as both toluene and water activity increased. Toluene permeance values exhibited a strong dependency on toluene vapor concentration. This concentration dependency was shown to be less intense at high water activity values. Similarly, the effect of water activity-at a specified toluene concentration-on the permeance of toluene diminished as the values of permeant concentration increased. These results illustrate the complex rela tionship of penetrant vapor concentration and water activity on organic vapor permeability through a multilayer structure.