Direct 3D Printing of High-Mass-Loaded Metal-Organic Framework Filaments with Excellent Adsorption Ability

Abstract

Conferring adsorptive properties to 3D printed materials by functionalizing thermoplastic polymers with metal-organic framework (MOF) materials paves the way for fused deposition modeling (FDM) 3D printing. However, to maintain the flexibility of the filament for printing, a low MOF loading mass (<10 wt %) must be maintained, which undesirably reduces the adsorption capability of the printed materials. In this study, 50 wt % HKUST-1 MOF is loaded into polyethylene glycol dimethyl ether (PEGDME) plasticized polylactic acid (PLA) to form a composite (HK@PLA-PEG-50). The high mass loading is achieved by the introduction of PEGDME as a plasticizer and the preparation of a homogeneous composite slurry. Without the post-printing process, the printed sorbent material with a high surface area of 547 m2 g-1 (49% relative to that of the originally prepared HKUST-1) has a CO2 adsorption capacity of 37.7 cm3 g-1 at 1 atm and 298 K, with a removal efficiency of 93.4% for 18 mg L-1 methylene blue (MB) solution. These results prove that HKUST-1 in the filament exhibits adsorption ability without hindrance from the polymer portion, which resulted from the high mass loading of HKUST-1 and led to the interconnection between the particles, thereby avoiding the blocking effect of the PLA polymer. This study demonstrates a promising method for preparing high-mass-loading HKUST-1 composite materials for FDM 3D printing and opens up the possibility of loading other MOF materials with unique properties into polymers for diverse applications. © 2025 American Chemical Society.