Submitted to: Green Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/9/2009
Publication Date: 11/17/2009
Citation: Liu, Z., Doll, K.M., Holser, R.A. 2009. Boron Trifluoride Catalized Ring-Opening Polymerization of Epoxidized Soybean Oil in Liquid Carbon Dioxide. Green Chemistry. 11:1774-1789. Interpretive Summary: In this research, we discovered a new method for making useful polymers from epoxidized soybean oil. Previous methods for making these materials used expensive and environmentally unfriendly solvents, like dichloromethane. With our new process, these useful materials can be made using a liquid form of carbon dioxide, a natural component of the air. Material made from this new process has all of the advantageous qualities of material made using conventional solvents. Moreover, the new process also produces a more easily purified product, because the carbon dioxide simply vaporizes when the material is removed from the pressure reactor. This is important because the targeted applications for these materials are pharmaceutical delivery and cosmetics. Our technology will help the soy based materials gain acceptance in these high value markets, benefiting both the end users and the agricultural industry.
Technical Abstract: Boron trifluoride diethyl etherate (BF3.OEt2) catalyzed ring-opening polymerization of epoxidized soybean oil (ESO), 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 deg C to -24.1 deg C. TGA results showed that the RPESO polymers were thermally stable at temperatures lower than 200 deg C and significant decomposition mainly occurred above 340 deg C. GPC results indicated the extracted soluble substances from RPESO polymers were smaller ESO oligomers.