Studies in the Drying Oils: XVII. Influence of Several Factors on the Mechanism of Drying of Oil Films

Abstract

The first stage in the drying of linseed oil films is a matter of oxidation or, more generally, of making polar molecules. The mechanism of reaction in this stage is greatly influenced by factors such as temperature and humidity. High humidity greatly inhibits and modifies the reactions occurring. The second stage in the drying involves association of the polar molecules produced in the first stage to form the solid gel-like coherent structure of the film. Some further oxidation occurs after the oil has “set,” but the film is soon oxidized to a stage corresponding to the addition of two oxygen atoms at each double bond, and the percentage of oxygen remains practically constant thereafter. The aging of films of linseed oil or of trilinolenic glyceride consists in a gradual transition of polar liquid phase to solid phase of substantially the same ultimate analysis. Embrittlement and failure of drying oil films is primarily a matter of reduction of the percentage of liquid phase to low values. © 1929, American Chemical Society. All rights reserved. © 1933, American Chemical Society. All rights reserved.