Boron trifluoride catalyzed ring-opening polymerization of epoxidized soybean oil in liquid carbon dioxide

Ring-opening polymerization of epoxidized soybean oil (ESO) catalyzed by boron trifluoride diethyl etherate (BF₃·OEt₂), in liquid carbon dioxide, was conducted in an effort to develop useful biobased biodegradable polymers. The resulting polymers (RPESO) were characterized by FTIR spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), ¹H NMR, ¹³C NMR, solid state ¹³C NMR spectroscopies and gel permeation chromatography (GPC). The results indicated that ring-opening polymerization of ESO occurred at mild conditions, such as at room temperature, and a subcritical CO₂ pressure of 65.5 bar. The formed RPESO materials were highly crosslinked polymers. The glass transition temperatures of these polymers ranged from −11.9 °C to −24.1 °C. TGA results showed that the RPESO polymers were thermally stable at temperatures lower than 200 °C and significant decomposition mainly occurred above 340 °C.