Solvent Free and Photocurable Polyimide Inks for 3D Printing
High performance three-dimensional (3D) printing materials are the key for the advancement and practical applications of emerging 3D printing technology and are still very few in market. In this work, photocurable polyimide inks for Digital Light Processing (DLP) 3D printing to produce constructs with excellent comprehensive property are presented. Maleic anhydride-terminated polyimide oligomers with glycidyl methacrylate graft were prepared by one-step imidization of phenolic hydroxyl groups containing diamine and aromatic dianhydride in high boiling-point solvent, followed by the reaction of glycidyl methacrylate with the phenolic hydroxyl groups. The good solubility of the oligomers in reactive diluents allows to form solvent-free photo-curable ink for DLP 3D printing to layer-by-layer deposit into polyimide complex shapes. The resultant photo-curable polyimide inks were capable of fabricating various complicated, precision architectures with good mechanical and thermoresistant properties. As such, the 3D printing polyimides are believed to be promising in building parts and models wherever heat-resistance, chemical inertness and high mechanical properties are required, such as micro-oil filter, through-tubing, cooling valve and various engine components.