Rigid,thermosetting liquid molding resins from renewable resources. I. Synthesis and polymerization of soy oil monoglyceride maleates

In this study, rigid thermoset polymers were prepared from radical copolymerization of the soybean oil monoglyceride maleates with styrene. In the first part of the study, soybean oil monoglycerides (SOMGs) were obtained from the reaction of soybean oil with glycerol at 220–240°C with an optimization of the reaction to maximize the monoglyceride yield. In the following step, SOMG were reacted with maleic anhydride at temperatures around 100°C to produce the SOMG maleate half esters. Different catalysts and different reaction conditions were examined to increase the maleate half esters' yields. The reactions were followed by IR and ¹H NMR, and the products were characterized by mass spectrometry. In the final step, the radical initiated copolymerization of the SOMG maleates with styrene produced rigid, thermoset polymers. The emulsion copolymerization of the SOMG maleates with styrene was also carried out successfully without the addition of an emulsifier. The obtained polymers were characterized by IR and the crosslinked network structure of the copolymers was examined with the swelling behavior in different solvents. Mechanical properties of the cured resin such as T_g, dynamic flexural modulus, and surface hardness were also determined. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 69–77, 2001