Design of 3D printed metal frame nested porous polyimide composites

Porous polyimide (PPI) can store oil, but the mechanical properties are also weakened by the pores. To solve this problem, a 3D printed metal frame-PPI nested composite (MFP) was proposed. The composite material has a binary pore structure (ordered submillimeter-level metal frame macropores and disordered micron-level PPI micropores). PPI material is filled in the metal frame, and the oil could be filled into the micropores, improving the mechanical and tribological performances. The preparation method was optimized and the mechanical, oil content, tribological properties of MFP were investigated. The experimental results showed that MFP enhance its ability to resist external deformation and has excellent mechanical properties and tribological properties. As the density of PPI filled in the metal frame increases, PPI is tightly bonded to the metal. Under the PPI filling density of 1.1 g cm-3 and sintering temperature of 330 degrees C, MFP could be well formed, and the friction coefficient is the lowest (0.035). MFP exhibits excellent mechanical and tribological performances.