Heterogeneous silicon rubber composite foam with gradient porous structure for highly absorbed ultra-efficient electromagnetic interference shielding. (12th April 2021)

• Record Type: Journal Article
• Authors: Yang, Jianming; Liao, Xia; Wang, Gui; Chen, Jia; Song, Pengwei; Tang, Wanyu; Guo, Fumin; Liu, Feng; Li, Guangxian
• Is Part Of: Composites science and technology. Volume 206(2021)
• Publication Date: 2021-04-12
• Subjects: Electromagnetic interference shielding -- High absorption -- Silicone rubber foam -- Supercritical carbon dioxide foaming -- Silver plated glass fiber; Composite materials -- Periodicals; Composite materials; Fibrous composites; Periodicals; 620.118
• DOI: 10.1016/j.compscitech.2021.108663
• Languages: English
• ISSNs: 0266-3538

Abstract

Abstract: Heterogeneous silicone rubber (VMQ)/silver plated glass fiber (Ag@GF)/multiwalled carbon nanotubes (MWCNT)/ferroferric oxide (Fe3 O4 ) composite foams with gradient porous structure were fabricated through layer by layer combination and supercritical carbon dioxide (scCO2 ) foaming. The average electromagnetic interference shielding effectiveness (EMI SE) and absorption coefficient (A) of the composite foam are as high as 78.6 dB and 0.82 respectively, because of the reasonable progressive dissipation mechanism. The resonance cancellation caused by the encounter of incident and reflected electromagnetic (EM) waves further improved the microwave absorbing performance of the foam, and an absorption ratio of up to 94% can be obtained at 7.68 GHz. Moreover, the composite foam exhibits excellent stability of EMI shielding performance under multiple bending. This composite foam has great application prospects in the field of EM protection of wearable flexible electronics, high-power instruments and the forthcoming 5th-Generation communication products. Graphical abstract: Heterogeneous EMI shielding composite foam with gradient porous structure was prepared through layer by layer combination and scCO2 foaming. The EMI SE and absorption coefficient (A) of the composite foam were as high as 78.6 dB and 0.82 respectively, due to the selective dispersion of Ag particles and the positive gradient distribution of MWCNT. Moreover, the peak value of A (0.94) was obtained at 7.68 GHz because of the resonance cancellation of electromagnetic (EM) wave, indicating 94% of the absorbed EM wave. The composite foam also exhibits outstanding stability of EMI SE and A value under 1000 repeated bending. Image 1 Highlights: A conductivity of up to 2809 S/m is obtained due to the effective distribution of Ag. Positive gradient distribution of MWCNT enhanced the absorbing properties. The EMI SE and A value of the foam are as high as 78 dB and 0.82 respectively. EMI SE and A value can be well preserved even after 1000 times of repeated bending. Extremely high peak of A (0.94) was observed at 7.68 GHz because of resonance.