Effects of Carbonization Temperature and Component Ratio on Electromagnetic Interference Shielding Effectiveness of Woodceramics

Abstract

Woodceramics were fabricated in a vacuum through carbonization of wood powder impregnated with phenol formaldehyde (PF) resin. The effects of carbonization temperature and mass ratio of wood/resin on electromagnetic interference (EMI) shielding effectiveness (SE) and morphology of woodceramics were explored. The PF resin made wood cell walls have the characteristics of glassy carbon. Wood axial tracheid and ray cells were filled with more glassy carbon by increasing addition of PF resin. Moreover, the increase of carbonization temperature was beneficial to improving SE. Woodceramics (mass ratio 1:1) obtained at 1000 °C presented a medium SE level between 30 MHz and 1.5 GHz.

Effects of fabrication parameters on the oxidation resistance of wood/phenolic resin carbon composites

“…The XRD results in this study illustrated the graphite-like, crystalline amorphous carbon structure of woodceramics, which was consistent with the research conducted by Qian et al 6 Nonetheless, the higher carbonization temperature contributed higher regularity of carbon. 20,21 Although woodceramics inherited the hierarchical porous structure of wood powder, providing abundant oxygen pathways for carbon contacts, 5 the higher carbonization temperature led to the increase of carbon content and crystallinity, and reduced the internal defects as well as heteroatoms of the woodceramics. Additionally, the carbon crystallization or crystallite growth would abate the reactivity of carbon materials.…”

“…Woodceramics are usually obtained through impregnating resin into wood or woody materials, and then carbonizating in vacuum conditions at high temperatures. [1][2][3] Woodceramics possess unique characteristics such as high wear and friction resistance, 4 electromagnetic shielding capacity, 5 and good mechanical properties. 6 Previous studies show that porous woodceramics have potential applications for catalyst supports, gas filtration, brake pads, etc.…”

Progress in polymers and polymer composites used as efficient materials for EMI shielding

“…In addition to reflection and absorption, the third mechanism of EMI shielding is multiply reflection, which refers to reflection of EM radiation from various surfaces, phase interfaces and in-homogeneities in the shield [20]. Materials with good ability of multiply reflection exhibit high specific surface area (foam or porous materials) or large phase interface (composites containing fillers with high specific surface area) [14,21]. The amplitude of incident radiation is attenuated by multiple internal reflections within the shielding material.…”

“…Based upon the outlined formulations it can be stated that efficiency of shielding by absorption is a function of σ.μ, whereas shielding by reflection is dependent on the ratio of both parameters σ/μ [14,31,41,42].…”

Tensile, electromagnetic, and far‐infrared properties of stainless steel/far‐infrared polyester composite materials

“…In addition, the 2016 report of WHO also warns all people that stay in an electromagnetic environment for a long time has caused serious health issues, which requires people to find solutions for this problem . The attenuation mechanisms of electromagnetic waves include reflection, absorption, and multi‐reflection . Usually, materials with a high conductivity or high magnetic permeability can shield electromagnetic waves, and the different intrinsic characteristics have different corresponding electromagnetic shielding mechanisms .…”