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. Keywords: 3D printing, Bismaleimide, Direct ink writing, Additive manufacturing