新型石墨烯改性电磁屏蔽硅橡胶材料的制备、性能与机理研究

Study on Preparation Property and Mechanism of Novel GrapheneModified Electromagnetic Shielding Silicone Rubber Material

本研究分别选择单层石墨烯(SLG)和少层石墨烯(FLG),并通过溶液分散法制备出两种高浓度石墨烯-硅橡胶母料;与导电银粉等助剂复配,后经机械共混法制备出两种石墨烯改性电磁屏蔽硅橡胶材料。结果表明,FLG改性提升导电银粉填充硅橡胶材料(GX/AA)的拉伸强度和拉断伸长率,而SLG改性则呈劣化趋势;SLG和FLG改性均明显提升GX/AA的导电性能;石墨烯改性电磁屏蔽硅橡胶材料在1.0×10-4~18 GHz频段内的电磁屏蔽效能均大于60 dB,最高可达78 dB。相互搭接的二维石墨烯片层起到桥联导电粒子的作用,形成的致密导电网络可以有效抵消外磁场,还可以增加电磁波在层间的多次反射和吸收损耗,进而提高材料电磁屏蔽效能。

Single-layer graphene modification(SLG)and few-layer graphene(FLG)were selected to prepare graphene-silicone rubber masterbatches with high concentration by solution dispersion method.Then the masterbatches were compounded with conductive silver powders etc.to prepare graphene modified electromagnetic shielding silicone rubber by mechanical blending method.The results indicated that FLG modification improved the tensile strength and elongation at break of conductive silver powder filled silicone rubber(GX/AA)composite,while SLG exhibited a deterioration trend.SLG and FLG modification could obviously improve the conductivity of GX/AA composite.The electromagnetic shielding effectiveness of GX/AA/SLG and GX/AA/FLG was more than 60 dB with a maximum of 78 dB in the frequency range of 1.0×10^(-4)-18 GHz.The overlapping two-dimensional graphene layers play the role of bridging the conductive particles to form a dense conductive network,which could offset the external magnetic field effectively,and also increase the multiple reflection and absorption loss of electromagnetic waves between layers,so as to improve the electromagnetic shielding efficiency of the material.