(266e) Development of Bioplasticizers from Soybean Oil

Plasticizers are high-boiling organic liquids that impart flexibility to polymers. Polyvinyl chloride (PVC), the third largest commercial plastic, is the primary polymer that utilizes plasticizers. The most commonly used plasticizers are a class known as phthalate esters. Recently the use of phthalates in products such as medical plastics, food contact materials, and children’s toys has come under intense scrutiny as they have been shown to cause negative health affects including hormonal disruptions, carcinogenic properties and developmental effects. Vegetable oils, especially soybean and high oleic soybean, are particularly suitable raw materials for developing new plasticizers due to their ready availability, low cost and ease of chemical modification. Numerous functional groups were introduced at the ester head group and on the back bone of the fatty acid esters to create changes in polarity and branching to enhanced PVC compatibility. The soybean oil triacylglycerols were converted to fatty acid esters by transesterification with various alcohols such as pentanol and glycerol, while the double bonds on the back bone were converted to epoxy function. The epoxy groups were ring opened with acetic acid to form estolide functions on the fatty acid back bone. The free hydroxyls were acetylated to give the final products. The resulting fatty acid esters showed excellent physical and plasticizer properties. They have low color, viscosities, and acid values. The plasticizers compounded with PVC gave low gelation times and temperatures with high thermal stability. The best performing bioplasticizers synthesized would be useful as replacements for phthalate plasticizers as they are non-toxic and perform equal to or better than current phthalate plasticizers.