A novel class of thermosetting resins based on allylated and transesterified epoxidized soybean oil (AE-ESBO) curable by radical mechanism was developed. The AE-ESBO was prepared from ESBO by oxirane ring-opening and then transesterification with allyl alcohol. A family of rubbery to glassy resins was prepared by radical copolymerization of AE-ESBO with different concentrations of maleic anhydride (MA). Glass transition temperatures (Tg) of these resins ranged from below room temperature to about 130 degrees C based on the amount of MA. In spite of the presence of anhydride groups, water absorption was low <2% even when maleic anhydride was 30% of total weight. Low sol content after extraction and low swelling in toluene indicated high crosslinking density. Tensile moduli of these resins were up to 1.4 GPa and tensile strengths up to 37 MPa. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012