[Journal of Materials Science & Technology] Lightweight and robust rGO/sugarcane derived hybrid carbon foams with outstanding EMI shielding performance
writer：Lei Wang#, Xuetao Shi#, Junliang Zhang, Yali Zhang and Junwei Gu*
keywords：electromagnetic interference shielding effectiveness, electromagnetic interference shielding effectiveness, graphene oxide
source：期刊
specific source：Journal of Materials Science & Technology
Issue time：2020年
Abstract: Increasingly severe electromagnetic pollution is now in urgent need of materials with lightweight, excellent flame retardancy, and outstanding electromagnetic interference shielding effectiveness (EMI SE). Renewable source-derived carbon foams and graphene have attracted extensive attention due to their 3D porous structure and remarkable electrical conductivity (σ). In this work, annealed sugarcane (ASC) was prepared by removal of lignin from sugarcane via hydrothermal reaction, followed by annealing treatment. Then graphene oxide (GO) was filled by vacuum-assisted impregnation process and thermally annealed to obtain the ASC/reduced graphene oxide (rGO) hybrid foams. When the loading of rGO is 17 wt.%, the ASC/rGO hybrid foam (density, ρ of 0.047 g/cm3) exhibits the optimal σ of 6.0 S/cm, EMI SE of 53 dB, specific SE (SSE = SE/ρ)/thickness (t) of 3830 dB·cm2/g, and compressive strength of 1.33 MPa, which is 76 %, 36 %, 13 % and 6 % higher than those of ASC, respectively. Moreover, ASC/rGO presents excellent flame retardancy, thermal stability, and heat insulation, which remains constant under burning on an alcohol lamp and presents low thermal conductivity of 115.19?mW/(m·K), close to the requirement for heat insulation. Synergistic effect of ASC and rGO not only significantly increase σ of ASC/rGO, but fully utilizes the capability of ASC and rGO to attenuate electromagnetic waves by virtue of unique porous structures and abundant interfaces. Such kind of lightweight EMI materials with excellent mechanical property, shielding performance, flame retardancy, and heat insulation is expected to tackle the key scientific and technical bottleneck problems of EMI materials, and will greatly expand the application of carbon nanomaterials in the field of aerospace industry.
隨著日益嚴重的電磁污染，低密度和高屏蔽效能的屏蔽材料的研發已變得尤為重要。受甘蔗的有序多孔結構啟發，通過水熱反應去除甘蔗中的木質素獲得水熱處理的甘蔗（SCHT）后將其退火，并借助真空輔助浸漬工藝填充氧化石墨烯后進一步熱還原，制備出輕質和高導電的退火甘蔗（ASC）/rGO雜化泡沫。當石墨烯的用量為17wt%時，ASC/rGO-3的密度僅為0.047g/cm3，展現出最大的壓縮強度、電導率、屏蔽效能和比效能/厚度，分別為1.33 MPa、6.04 S/cm-1、53 dB和3830 dB·cm2/g。并且，ASC/rGO-3還具有優異的阻燃性能、熱穩定性和隔熱性能，能夠在酒精燈灼燒下無變化和接近于絕熱要求的熱導率（115.2 mW/(m·K)）。獨特的有序多孔結構和豐富的界面增強了ASC/rGO-3對電磁波的損耗能力，屏蔽機理主要以吸收為主。這種輕質，具有優異的力學性能、屏蔽性能、阻燃性能力和隔熱性能的屏蔽材料將極大地拓展碳納米材料在航空航天工業中的應用。