3D Printing of Delicately Controllable Cellular Nanocomposites Based on Polylactic Acid Incorporating Graphene/Carbon Nanotube Hybrids for Efficient Electromagnetic Interference Shielding

Control of the architectures of three-dimensional (3D)-printed cellular parts to achieve electromagnetic interference (EMI) shielding protection is a challenging issue. In this paper, by combining FDM 3D-printing technology with hybridizing strategy, we successfully designed and fabricated high-performance polylactic acid nanocomposites incorporating graphene/carbon nanotube hybrids (PLA/GNPs/CNTs) and delicately controllable 3D-printed cellular parts. PLA/GNPs/CNTs nanocomposites prepared under the optimum conditions possessed the excellent comprehensive performance: Their tensile strength and Young's modulus can achieve values 16.2 and 25.5% higher than those of pure PLA, respectively. The corresponding electrical conductivity can reach 82.0 S/m, and EMI shielding efficiency can achieve 36.8 dB, which is far beyond the commercial shielding standard (20 dB). In addition, the 3D-printed cellular parts were successfully fabricated with light weight and highly efficient EMI shielding property. Finally, a cellular factor (Tcell) was innovatively adopted to quantitatively evaluate the relationship between cell structures and EMI shielding behaviors of 3D-printed cellular materials, indicating that the critical cell size of about 4.29 mm could be successfully fitted to maintain the suitable shielding efficiency in X-band frequency range. These related investigations provide a new theoretical mechanism for evaluating the EMI shielding performance of 3D-printed cellular materials and open up new spaces for construction of the lightweight and multifunctional cellular parts for EMI protection applications.