Design and fabrication of hierarchically porous polymer composites by powder bed fusion

Materials with adsorption functions have a wide range of applications in gas storage and separation, water purification, catalysis, etc. However, most of them show weak ability to form a specific shape, which limitstheir practical application. Additive manufacturing has the characteristic to manufacture complex structures, particularly forming porous structures. This paper demonstrates a universal method to manufacture hierarchical porous functional components by powder bed fusion (PBF). The porous structure at different scales was created through the design of the part, addition of milled salt as porogen and the addition of activated carbon (AC). The activated carbon had a dual function: pore integration with microscopic pores and adsorption. Once dissolved, the salt created macropores; while a lattice structure was adopted for the design of the component, which can further increase the macroscopic pores of the component and maximize the adsorption capacity. The carbon dioxide (CO₂) adsorption capacity of sintered components with different AC/Polyamide12 (PA12) ratios and porous structures was tested. The 40 wt% AC content exhibited a high CO₂ adsorption capacity of 22.71 cm³/g at 1 bar at 25 °C. The addition of salt as a method of enhancing the porous structure led to approximately 43 % improvement over the typical standard AC/PA12 porous structure.