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 nano-silica/carbon black/epoxy(SiO2/CB/EP)composites through alternately arranging nano-silica/epoxy(SiO2/EP)composites with high strength and car-bon black/epoxy(CB/EP)composites with high conductivity.According to the rheological properties,the epoxy com-posites 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 manufac-turing 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.