Fused Filament Fabrication of COC/Aluminum Composites for Structured Reactor Components

The development of 3D-printable polymer–metal composites offers new opportunities for structured catalytic reactor design and process intensification. Here, cyclic olefin copolymer (COC) composites filled with micron-scale aluminum particles (1–15 wt%, 160 µm) were prepared via a two-step compounding and extrusion process to produce filaments suitable for fused filament fabrication (FFF). Thermal analysis confirmed that aluminum incorporation does not significantly alter the glass transition (Tg = 76–77 °C) or thermal stability of the polymer. Melt flow rate measurements indicated processable viscosity (MFR 3.82–4.57 g/10 min), while tensile testing revealed Young’s modulus of 1277 MPa–1783 MPa, maximum stress of 27 MPa–39 MPa, and enhanced strain at break for the 1 wt% Al composite (εB = 5.33%). Composites containing up to 15 wt% Al were successfully printed into mechanically robust static mixers, demonstrating complex geometries without particle sedimentation issues. The incorporation of aluminum particles introduces potential functionalities related to thermal management, surface modification, and future catalytic or photocatalytic applications. This work establishes a scalable polymer–metal platform integrating structural stability, geometric complexity, and prospective multifunctional behavior for advanced flow-reactor applications.