Vapor-Phase Acetylation of Piled Sheets of Cellophane

Vapor-phase acetylation was carried out on samples of piled cellophane sheets that had been impregnated with sodium or potassium acetate. In the case of the samples of 10 sheets, acetic acid content of each sheet did not depend on the situation in the pile but on the kind and amount of impregnants. This is discussed in terms of accessi bility. In the case of the samples of 20 sheets, some sheets in the deepest situation contained the same amount of free acetic acid as the outside sheet did, but were hardly acetylated. This is explained by the difference in penetration rate between acetic acid and acetic anhydride. With these and other facts in mind, it has been concluded that the cross section of acetylated high-tenacity rayon is uniform in acetic acid content.