Catalyzed ring-opening polymerization of epoxidized soybean oil by hydrated and anhydrous fluoroantimonic acids

Ring-opening polymerization of epoxidized soybean oil (ESO) catalyzed by a superacid, fluoroantimonic acid hexahydrate (HSbF₆·6H₂O) and the anhydrous form (HSbF₆) in ethyl acetate was conducted in an effort to develop useful biodegradable polymers. The resulting polymerized ESO (SA-RPESO and SAA-RPESO) was characterized using infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis (TGA), ¹H-NMR, ¹³C-NMR, solid-state ¹³C-NMR and gel permeation chromatography (GPC). The results indicated that ESO was effectively polymerized by fluoroantimonic acid and formed polymers with relatively high cross-link density. Glass transition temperatures of these polymers ranged from –13°C to –21°C. TGA results showed the SA-RPESO and SAA-RPESO polymers were thermally stable at temperatures up to 200°C. Decomposition of the polymers was found to occur at temperatures greater than 350°C. GPC results indicated the extracted soluble substances from SA-RPESO polymers were oligomers of ESO. These soybean oil–based polymers will be explored for application in the personal and health care areas.