Construction of Bionic Porous Polyetherimide Structure by an In Situ Foaming Fused Deposition Modeling Process

The biological hierarchical porous structures have excellent properties that are unmatched by artificial fabrication and have great potential for applications in catalysis, adsorption, energy and biomedicine. However, the traditional fabrication methods are difficult to mimic finely hierarchical porous structures and involve complex solution handling and residues. 3D printing is limited by materials and resolution, making it difficult to achieve microporous preparation. Herein, an in situ foaming fusion deposition modeling (FDM) technology using environmentally friendly CO 2 as blowing agent to fabricate polyetherimide bionic hierarchical porous structures is applied. The macroscopic pores are obtained by 3D design, while the microporous structure is regulated by changing foaming parameters such as saturation pressure, desorption time, and nozzle temperature. The cell size of the microextruded fibers by FDM nozzle vary from 1.3 to 5.3 μm and the cell density vary from 7.3 × 10 8 to 1.0 × 10 10 cell cm −3 with the change of parameters. In addition, the deposited hierarchical porous scaffold with density of 0.89 g cm −3 possess a compressive strength of 78.9 MPa at 15% strain and a compressive modulus of 1454.3 MPa, which exhibits comparable mechanical property with that of bone.