Sustainable eucommia ulmoides gum composites with outstanding electromagnetic wave absorption properties

Composites with high electromagnetic wave absorption were prepared using Eucommia ulmoides gum (EUG) as a matrix and Fe3O4@polyaniline (PANI) core-shell materials as electromagnetic-wave-absorbing agents. The morphology and mechanical properties of Fe3O4@PANI/EUG composites were characterized, along with the electromagnetic-wave-absorbing properties and its mechanism. The morphology of Fe3O4@PANI/EUG composites showed that Fe3O4@PANI were uniformly dispersed in the matrix and formed a dense filler network which was benefit for high electromagnetic wave absorption. The interface between the crystalline and amorphous phases within the EUG matrix can accumulate electrical charges, leading to polarization loss and thereby enhancing electromagnetic wave absorption. Fe3O4@PANI/EUG composites has the minimum reflection loss of -48.98 dB at 7.46 GHz, and its effective bandwidth with a reflection loss below -10 dB in the range of 5.05-9.06 GHz. The outstanding performance is attributed to enhanced impedance matching, interfacial polarization originating from the core-shell and shell-polymer interfaces, as well as polarization loss caused by the boundary between crystalline and amorphous phases within the EUG matrix.