High-Performance Carbonized Waste Corrugated Boards Reinforced with Epoxy Coating as Lightweight Structured Electromagnetic Shields

Recycling is a key component of the "Reduce, Reuse and Recycle" waste hierarchy, and recycling of waste corrugated boards through the reprocessing of them into new functional materials is of great significance from the perspective of "waste to wealth" and sustainability. Herein, high-performance carbonized waste corrugated boards (CCB) reinforced with epoxy coating as lightweight structured electromagnetic (EM) shields were demonstrated, and the resultant CCB samples not only exhibited excellent shielding effectiveness (SE) of similar to 46.0-82.0 dB and ideal special SE value of similar to 325-1171 dB/(g/cm(3)) related to their carbonization temperature or different types at the frequency region of similar to 8.2-12.4 GHz (X-band), but also showed superior thermal-insulation capability, comparable to expanded polypropylene foam. Such shielding performance should ascribe to their high electrical conductivity, as well as special structure (sawtooth pattern sandwiched between two parallel surfaces), capable of internal multiple reflections and constructive interference. Moreover, the further construction of an ultrathin graphene skin-layer on the CCB surfaces could reduce the carbonization temperature while keeping their SE value, suggesting an effective and facile approach for energy-saving.