Chapter 2: Natural Epoxy Oil (Euphorbia Oil) Polymerization in Liquid Carbon Dioxide–Green Solvents^† Check Access

Aside from being renewable, non-toxic, non-polluting, biodegradable and environmentally friendly, vegetable oils also possess renewable properties. Due to these properties, vegetable oils have been used in a variety of industrial applications, such as plastics, lubricants, adhesives, inks, fuels/biodiesel, coatings, printing inks, varnish solvents and surfactants. Many researchers have reported the production of polymers from vegetable oils, specifically from epoxidized soybean oil (ESO). However, ESO must be synthesized using conventional synthetic routes and some of the synthesized epoxide rings can degrade during the process. Plant oils with an epoxidized ring have been investigated to overcome this shortcoming. One such plant oil is euphorbia oil (EuO). This chapter discusses the ring-opening polymerization of EuO in a liquid carbon dioxide–green solvent using the boron trifluoride diethyl etherate (BF₃·OEt₂) catalyst. A variety of analytical techniques have been used to characterize the material, including FTIR, ¹H-NMR, ¹³C-NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and gel permeation chromatography (GPC). Using subcritical carbon dioxide (CO₂) and a pressure of 65.5 bar, the ring-opening polymerization of euphorbia oil (RPEuO) was carried out under mild conditions, such as at room temperature. It was found that the cross-linked polymers formed by RPEuO had glass transition temperatures ranging from −15.0 °C to −22.7 °C. RPEuO polymers were thermally stable below 220 °C, and decomposition occurred above 340 °C, according to the TGA results.