Abstract: Epoxidized linseed oil is a type of epoxy resin synthesized by the epoxidation reaction of linseed oil. Thermosetting epoxy resin-based polymer composites with a variety of properties can be prepared after the reaction of epoxy resin and curing agents, which can be used in many fields. In this work, the curing reaction of epoxidized linseed oil was studied and the optimized reaction conditions were also obtained by the application of orthogonal experimental method based on the best selection of curing agent and accelerator. Fourier transform infrared spectroscopy（FT-IR）and differential scanning calorimetry（DSC）techniques were applied to investigate the curing reaction process and characterization. The results show that a mixture of maleic anhydride and phthalic anhydride (molar ratio 0.83﹕0.17) was the best curing agent while N, N-dimethylbenzylamine was the best accelerator. The factors impacting curing reaction were in the order of mixed anhydride/epoxy ratio > temperature > amount of accelerator > time. Curing degree of the final product could reach 97.13% under the following optimized conditions: mixed anhydride / epoxy ratio was 1.2﹕1.0 (molar ratio), the amount of accelerator was 2.5%, the temperature and time were 120 ℃ and 4 h,respectively. IR characteristic absorption of epoxy and anhydride gradually disappeared as the proceeding of the reaction and the curing reaction tended to be complete. Curing reaction of epoxidized linseed oil with mixed anhydride is an exothermic one with peak temperature at 182.6 ℃ and reaction enthalpy is -130.2 J/g.

Key words: epoxidized linseed oil, anhydride, curing reaction, curing degree