3D printing of epoxy-based composites with high strength and electromagnetic interference shielding ability.

A dual-material 3D printing technique is developed to rationally construct namrsilica/carbon black/epoxy (SiO₂/CB/EP) composites through alternately arranging nano-silica/epoxy (SiO₂/EP) composites with high strength and carbon black/epoxy (CB/EP) composites with high conductivity. According to the rheological properties, the epoxy composites with 11. 6 wt. % SiO₂ and 10 wt. % CB exhibits excellent printability. A stable diameter of 400 μm was achieved through controlling the extrusion pressure and printing speed. The SiO₂/CB/EP composites show an excellent manufacturing accuracy and a highly ordered 3D structure as verified by the optical and micro-CT images. The tensile, compres-sive and bending strengths of the SiO₂/CB/EP composites were 35 MPa, 64 MPa and 120 MPa, respectively, indicating that there is no attenuation compared to those of the SiO₂/EP composites. Moreover, the electromagnetic interference shielding effectiveness of the composites is as high as 25 dB on the basis of the microwave absorbing mechanism. [ABSTRACT FROM AUTHOR]