Additively manufacturing high-performance bismaleimide architectures with ultraviolet-assisted direct ink writing

Bismaleimide (BMI), as a high-performance thermosetting resin, has been widely used to many cutting-edge fields, but the ability of difficult to dissolve and complicated post-treatment process has hindered the applications of BMI in Additive manufacturing technology. In this study, additive manufacturing of BMI is realized via UV-assisted direct ink writing (UV-DIW) of BMI resin inks followed by heat treatment. The inks are composed of prepolymer 4,4′-bismaleimidodiphenyl methane and 2,2′-diallylbisphenol A, diluent N-vinyl-2-pyrrolidone, and photo initiator Irgacure 819, which exhibit desirable UV curing performance and rheological properties for additively manufacturing various complex three-dimensional (3D) structures via UV-DIW at room temperature. The followed heat treatment results in BMI architectures with excellent mechanical properties, dimensional stability and thermoresistant properties with ~91 MPa tensile strength and at the same time realize the shrinkage of 2–3%, ~4 GPa Young's modulus, exceeding 370 °C decomposition temperature, and ~210 °C glass transition temperature, which are comparable to that of traditionally molding BMI. The 3D architectures with outstanding performances are promising in fields ranged from microelectronics to aerospace and automotive industries.