Linseed Oil

Linseed oil is a triglyceride, like other fats. Linseed oil is distinctive for its unusually large amount of α-linolenic acid, which has a distinctive reaction with oxygen in air. Specifically, the fatty acids in a typical linseed oil are of the following types:[3] The triply unsaturated α-linolenic acid (51.9–55.2%), The saturated acids palmitic acid (about 7%) and stearic acid (3.4–4.6%), The monounsaturated oleic acid (18.5–22.6%), The doubly unsaturated linoleic acid (14.2–17%). Having a high content of di- and tri-unsaturated esters, linseed oil is particularly susceptible to polymerization reactions upon exposure to oxygen in air. This polymerization, which is called "drying", results in the rigidification of the material. The drying process can be so exothermic as to pose a fire hazard under certain circumstances. To prevent premature drying, linseed oil-based products (oil paints, putty) should be stored in airtight containers. Like some other drying oils, linseed oil exhibits fluorescence under UV light after degradation.[4] Representative triglyceride found in a linseed oil, a triester (triglyceride) derived of linoleic acid, alpha-linolenic acid, and oleic acid. Uses Most applications of linseed oil exploit its drying properties, i.e., the initial material is liquid or at least pliable and the aged material is rigid but not brittle. The water-repelling (hydrophobic) nature of the resulting hydrocarbon-based material is advantageous.