Microcellular foamed polyamide 6/carbon nanotube composites with wave

Electromagnetic (EM) wave pollution causing damage to precision equipment and threatening the health of living organisms has attracted considerable attention. Herein, promising microcellular foamed polyamide 6 (PA6)/carbon nanotube (CNT) composites for highly efficient EM wave absorption were successfully fabricated using supercritical CO 2 foaming. Nanocomposites foams with a void fraction ranging from 38.7% to 85.1% were achieved, providing a platform to assess the correlation of the electrical conductivity, the dielectric permittivity and the EM wave absorption properties with porosity. Notably, the Foam-257.5C sample with a void fraction of 38.7% exhibited outstanding EM wave absorption characteristics at a thickness of only 1.59 mm and an ultra-low reflection loss value of -55.3 dB (99.9997% wave absorption). Most importantly, the effective absorption bandwidth (EAB) of the Foam-257.5C sample could cover the entire Ku band (12.4-18 GHz) by slightly adjusting the thickness from 1.20 to 1.60 mm. The superior EM wave absorption performance of the Foam-257.5C sample was attributed to multiple reflections and scattering at the solid-gas interfaces, favorable impedance matching due to the existence of a large polymer-air interface area, conductive loss near the interfaces and interfacial polarization. Thus, this study offers an eco-friendly, simple and versatile methodology to develop high-efficiency, flexible polymer-based EM wave absorbents.

Automated summary

The study successfully fabricated microcellular foamed polyamide 6/carbon nanotube composites with high-efficiency electromagnetic wave absorption using supercritical CO2 foaming. This eco-friendly and versatile methodology offers a simple way to develop flexible polymer-based electromagnetic wave absorbents.