Synthesis and Characterization of the Intrinsic Properties of Milkweed Polyhydroxy Fatty Acids

Seed oils consist mainly of triglycerides, that is, they comprise a unit of glycerol backbone esterified with three acyl groups (usually but not limited to C16-C18) which may be saturated or unsaturated with one or more olefinic functionalities per acyl group. Very rarely do seed oils contain additional functional groups, such as hydroxyls as in castor and lesquerella seeds. Milkweed seed oil follows the natural triglyceride patterns, but with a difference in being highly poly olefinic. This character allows for the introduction of different reactive groupings into the structure of the oil so as to be amenable to tailoring to a variety of uses. Synthesis of the milkweed polyhydroxy triglyceride (MWPHTG) from the polyoxirane triglyceride derivative of milkweed oil using in situ peroxy acid epoxidation of the oil was previously reported. Subsequent acidolysis of the epoxy derivative gave the MWPHTG. Here the polyhydroxy triglyceride was saponified for glycerol removal thus generating the polyhydroxy fatty acids of milkweed oil. Studies of the physical characteristics, flow and stability of the resulting hydroxylated fatty acids using FTIR, NMR, DSC, Rheometry and TGA indicate a stable material with unique properties that would be useful as additives in many applications such as pharmaceuticals.