Three‐dimensional printing of high‐performance polyimide by direct ink writing of hydrogel precursor

Abstract

AbstractThree‐dimensional (3D) printing of all‐aromatic polyimides (PIs) is attracting extensive attention due to the advantages of excellent comprehensive performances and complex structures. It still remains challenges because of some drawbacks, such as poor solubility and infusibility, and the environmental unfriendly preparation. Here, polyamide acid salt (PAAS) hydrogels were prepared by the reaction of polyamide acid (PAA) with organic amines in water. PAAS hydrogels had remarkable rheological properties, which made it applied in direct ink writing 3D printing. The printed objects were finally converted into high‐performances PI objects with prominent mechanical properties and thermal stability. Not only so, the advantages also include simple preparation, less organic solvent, low thermal imidization temperature (250°C), controllable macrostructure and porous microstructure, and the present 3D printed PI by PAAS was expected to significantly promote the application potentials. In this study, thermal conductivity (100°C) of the PI objects after structure design and 3D printing was reduced from 0.102 W m−1 K−1 to 0.061 W m−1 K−1, and density was reduced from 0.4562 g cm−3 to 0.2731 g cm−3.