Sandwich structures based on fused filament fabrication 3D‐printed polylactic acid honeycomb and poly(vinylidene fluoride) nanocomposites for microwave absorbing applications

Abstract

AbstractPolylactic acid (PLA)—based honeycomb samples with different cell sizes and thickness were prepared using the fused filament fabrication (FFF) 3D printing technology and used to build sandwiched multilayer structures consisted of the honeycomb as the core component and poly(vinylidene fluoride) (PVDF) and/or PVDF/carbon nanotube (CNT) nanocomposites as top and bottom layers. The effect of the honeycomb design (cell size and thickness) and the presence and nature of the impedance matching layer on the microwave absorbing properties of the corresponding structures was investigated in the X‐band (8.2–12.4 GHz) and Ku‐band (12.4–18 GHz). For the systems without matching layer or with neat PVDF film as the matching layer, the honeycomb with larger thickness (5 mm) and larger cell size resulted in better electromagnetic wave attenuation but narrow frequency bandwidth with RL below −10 dB. The best combination minimum RL value (−18 to −14 dB) and broad frequency bandwidth with attenuation higher than 90% (around 8 GHz) was achieved with honeycomb of 2 mm thickness sandwiched by PVDF/CNT05 as the matching layer and bottom layer constituted by PVDF/CNT1 film, regardless the cell size of the honeycomb. These results indicate the PLA honeycomb as promising candidate as component for multilayer microwave absorbing materials and open new possibilities of applications of FFF technology for designing flexible, lightweight, and low‐cost materials to be used in both civil and military industries.