Film Properties of Glyceryl Esters of Various Octadecadienoic Acids

The effect of cis and trans isomers in isolated and conjugated structures of glyceryl esters of octadecadienoic acids on film formation was examined with respect to drying time, film quality and after‐tack. Little difference in the drying rates of the conjugated trans‐trans and cis‐trans oils was observed. Oils based on octadecadienoic acids with a high content of either conjugated or isolated double bonds dried at a slower rate than blends of these two types. A minimum drying time occurred when 60 ± 5% of conjugated oils were blended with 40 ± 5% of isolated diene oils. This is related to the faster oxygen uptake and peroxide formation of the isolated cis structure. This peroxide acts as the initiator for vinyl‐type polymerization. The drying rate of isolated trans diene oils is directly related to the trans content. The development of after‐tack appears to be related to the trans content. The conjugated trans‐trans esters heat‐polymerize more rapidly than the conjugated cis‐trans.