Effect of barbituric acid on the self‐polymerization reaction of bismaleimides

Abstract Barbituric acid (BTA) was used as an initiator for the homopolymerization of bismaleimide (BMI). The reaction was controlled by the amount of barbituric acid and ended up with solvent‐soluble oligomers. The effects of varying the amounts of BTA, as well as the reaction time, on BMI's self‐polymerization reaction were investigated. The thus‐formed oligomers were characterized by gel permeation chromatography (GPC), infrared spectra (IR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The degree of reaction increased proportionally to the concentration of BTA or the length of the reaction time. Thus, solvent‐soluble BMI oligomer can be controlled and obtained.