Research progress of wood-based electromagnetic interference shielding/wave absorbing materials
Life health,precision instruments,and national defense safety seek for the high performance and green elec-tromagnetic shielding/wave absorbing materials.However,traditional metal-based materials have drawbacks of low shielding effectiveness-to-density ratio,secondary environmental pollution,and single shielding mechanism.Mean-while,carbon-based nanomaterials are complex to prepare and expensive.Wood and its derivatives have natural ad-vantages such as multi-level pore structure,high strength-to-weight ratio,environmental friendliness,easy processing,and renewability.As a result,they have been considered as suitable materials for developing lightweight,environmentally friendly electromagnetic shielding/wave absorbing materials.This review first introduced the basic principles of electromagnetic shielding and wave absorption,and elucidated the relationship between relevant electro-magnetic parameters and shielding performance.The characteristics and application of three common preparation meth-ods were compared,including coating,filling,and carbonization.The coating-type deposits different conductive layer to the surface of the wood,which is facile and able to maintain the high-strength of wood,but the performance is highly dependent on the coating material.Filling-type is to add the conductive or magnetic filler into the wooden struc-ture,and delignification is also applied for better distribution of conductive or magnetic components.It can be used in the wearable electronic device,but the preparation is complex.Carbonization-type refers to heat the wood to tempera-tures above 800℃ for obtaining conductive skeleton,and conductive or magnetic components are added to further im-prove the performance.Although high performance can be achieved,their mechanical properties are poor.This review then summarized the effects of preparation,pore structure,and conductive/magnetic components on the electromag-netic shielding/wave absorbing performance.The performance usually increases with the electrical and magnetic con-ductivity,thus,the addition of the conductive or magnetic components is often applied to improve the performance.The orthotropic structure of the wood-based materials also manipulates the electromagnetic shielding mechanism,hence the shielding performance along the grain direction and perpendicular to the grain direction is different.The main wave absorbing mechanism is the multi-internal reflection of electromagnetic inside the pores,hence porous structure and porosity play a vital role in improving the performance,and low-density wood species is chosen.Finally,the de-velopment trend and research focus of wood-based electromagnetic interference shielding/wave absorbing materials is prospected.This study can provide the background information for the future development of the wood-based electro-magnetic interference shielding/wave absorbing materials.
woodelectromagnetic interference shieldingelectromagnetic wave absorptionwood-based electromagnetic shielding materialwood-based absorbing material
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维普
