Thermosetting Allyl Resins Derived from Soybean Oil

A new class of biopolymers based on plant oils with allylic double bonds was prepared from vegetable oils by oxirane ring-opening. Investigation of model systems revealed that the main side reactions during ring-opening were formation of intramolecular cyclic ethers in epoxidized linoleic fatty ester and oligomerization. Side reactions in the epoxidized oleic fatty ester were insignificant. Allyl alcohol ring-opened epoxidized soybean oil (AESBO) was then copolymerized with maleic anhydride (MA) to prepare thermosetting resins by free radical polymerization and esterification. In the best case, high gel content (99%), low water absorption (similar to 1%), and low swelling ration in toluene (similar to 4%) were achieved. Glass transition temperatures of these resins ranged from below room temperature to about 123 degrees C depending on the loading of MA. Tensile modulus varied from few MPa to 1.1 GPa, with the highest tensile strength of 29 MPa.