Superior wave-absorbing performances of silicone rubber composites via introducing covalently bonded SnO2@MWCNT absorbent with encapsulation structure

SnO2@MWCNT wave absorbent was firstly fabricated via a hydrothermal process followed by heat treatment. Then SnO2@MWCNT/silicone rubber wave-absorbing composites were obtained by solution casting method. XRD, Raman, TGA, XPS, and TEM analyses indicated the successful preparation of covalently bonded SnO2@MWCNT absorbent with encapsulation structure. When the mass fraction of SnO2@MWCNT was 7.5 wt% and the sample thickness was 2.6 mm, the SnO2@MWCNT/silicone rubber wave-absorbing composite displayed the minimum reflection loss (RLmin) of 56.9 dB and effective absorption bandwidth (EAB) of 3.1 GHz. The outstanding wave-absorbing performances of SnO2@MWCNT/silicone rubber wave-absorbing composites could be ascribed to the excellent impedance matching and dielectric loss capability. Furthermore, the corresponding 7.5 wt% SnO2@MWCNT/silicone rubber wave-absorbing composite exhibited heat resistance index (THRI) of 196.3 degrees C, higher than that of neat silicone rubber (187.4 degrees C).