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1、1,Microcellular graphene foam for improved broadband electromagnetic interference shielding石墨烯泡沫应用于宽屏电磁波屏蔽Wentao Zhai翟文涛Ningbo Institute,CAS中科院宁波材料所20161018,Our research interests我们的研究兴趣,Development of extrusion foaming technology开发连续挤出发泡技术,Extrusion foaming system with using CO2 as the blowing agen
2、t;以超临界CO2流体为发泡剂 Regular PP was used to produce PP foam 通用PP用作发泡体系,Development of autoclave foaming technology开发釜压发泡技术,EPP,EPP,EPLA,EPI,ETPU,Our research interests我们的研究兴趣,4,Development of multi-functional polymer foam film开发多功能聚合物发泡薄膜,Our research interests我们的研究兴趣,5,Advantages of(microcellar)foaming微
3、发泡的优势,lightweight/轻量化;Thermal insulation/隔热;Sound insulation/隔音；Improved impact/cushion properties/提高了冲击/缓冲性能；Reduced dielectric properties/降低了介电性能,Absorbing the microwave as a maze structure;为电磁波提供迷宫结构；,EMI shielding materials电磁屏蔽材料,Advantages of(microcellar)foaming微发泡的优势,EM interference effects 电磁
4、干扰 Compromise the performance and lifetime of devises Interfere with the function of other nearby components EM information leakage 电磁泄露Computer,cell phone,To damage the human body 危害人体,Harmful effects of EM wave电磁波的危害,8,Radar detection雷达探测,Electromagnetic stealth materials,Radar detection:Broad ban
5、d EM wavetransmitted or received by radar,Classical protection against EMIMetal sheetsBut:high density Poor mechanical flexibility Corrosion Limited tuning of the shielding effectiveness(SE),Advantages brought by polymersEasy shapingLightweightLow costBut most polymers are transparent to the EMI wav
6、eMethods to improve the EMI SE of polymersTo disperse electrically conductive fillers in polymer matrix,The carbon materials such as carbon black,graphite,carbon nanotube,graphene nanosheets are usually selected as the conductive fillers.,Classical materials for EMI shielding经典的电磁屏蔽材料,Novel cellular
7、 structure of polymer composites for EMI shielding,Polymer/conductive filler composite,Polymer/conductive filler composite foam,Tendency of EMI shielding materials电磁屏蔽材料发展趋势,Lighter/轻量化Thinner/更薄Higher EMI SE/更高的屏蔽效能For the application in special fields such as aerospace,weapon equipment,microelectr
8、ionics.Superior thermal stability/耐高温Flame retardancy/阻燃Excellent mechanical properties/有益的性能Flexible/柔性,High Tg:220C;Flame retardant;Solid stat foaming using compressed CO2 as the physical blowing agent,Preparation of high performance PEI microcellular foam 制备高性能PEI微发泡材料,Miller,D.et al.,Polymer,201
9、1,52,2910.,Published data of microcellular high performance foam/发表的高性能聚合物发泡材料论文,Expansion ratio lower than 5 times膨胀倍率低于5倍,Method to improve the expansion ratio of PI microcellular foam/提高膨胀倍率的方法,Density：90 kg/m3,Expansion rate:15times,W.T.Zhai*,W.W.Feng,J.Q.Ling,W.G.Zheng,Ind.Eng.Chem.Res.,2012,51
10、,12827.THF as a co-blowing agent,Tg:265 C,Cell size：2030 m,Cell morphology of microcellular PI bead foam PEI微发泡粒子的泡孔形态,Compression molding of PI bead foam模压粘结成型,Tg:230C,50 times expansion/50倍膨胀;,翟文涛，郑文革，凌建强，中国发明专利，201210171721.X,翟文涛，郑文革，冯卫卫，凌建强，中国发明专利，201210170254.9,PI microcellular foam with superh
11、igh volume expansion/制备超高倍率PI泡沫,Compression molding模压成型,High processing temperature up to 320-360 C/加工温度高达320-360度；High viscosity of composite melt and difficult to disperse high content of nanofillers/体系粘度高，难以分散;Difficult to achieve a high foam expansion ratio/难以得到高的膨胀倍率；A high filler content requi
12、rement to achieve a good EMI shielding properties/优异的屏蔽效能需要添加高含量的吸收剂！,Challenging in the preparation of PI composite foam with high filler loading 制备高填充PI复合材料泡沫的挑战,20,Method to solve the challenging/解决办法,Preparation of PEI/graphene microcellular foam/制备PEI/石墨烯发泡材料,J.Q.Ling,W.T.Zhai*,W.W.Feng.et al.,
13、ACS Appl.Mater.Interfaces,2013,5,2677.B.Shen,D.D.Lu,W.T.Zhai*,et al.,ACS Appl.Mater.Interfaces,2013,5,11383.,PEI/Graphene/DMF solution,Sample size:2.3 mm,22,EMI SE test/电磁屏蔽效能测试,R&S ZVA67 vestor network analyzer 网络分析仪 Sample size:22.5 mm 10.0 mm,For the commercial usage 20dB商用电磁屏蔽材料需要效能大于20dB,PEI/gr
14、aphene microcellular foam used for EMI shielding/电磁屏蔽效能,24,Preparation of high thermal stable PI/graphene microcellular foam/制备泡沫,The improved dispersion of graphene oxide by in-situ polymerization通过原位聚合来改善氧化石墨烯的分散,Y.Li,W.T.Zhai*,et al.,RSC Adv.,2015,5,24342.,25,Cell morphology of PAA/graphane and P
15、I/graphene microcellular foams/泡孔形态,Samples with the thickness of 0.8 mm样品厚度仅为0.8毫米,EMI SE of PI/graphene microcellular foam/PI/石墨烯泡沫的电磁屏蔽效能,27,Preparation of carbon/graphene microcellular foam/制备石墨烯/碳泡沫,Y.Li,W.T.Zhai*,et al.,Carbon,2016,100,375-385.,PI(350C)Carbonization(1000-1500C)Graphitization(2
16、100-2600 C),Cell morphology evolution during the pyrolysis/碳化/石墨化过程中泡孔结构的演变,EMI SE of carbon/graphene microcellular foam/石墨烯/碳复合泡沫的屏蔽效能,Preparation of graphene film by direct evaporation of GO suspension/GO薄膜,self-assembly of GO into the GO film 自组装成GO薄膜；GO was thermal reduction into graphene film；热
17、还原成石墨烯薄膜,B.Shen,W.T.Zhai*,W.G.Zheng*,Advanced Functional Materials,2014,24,4542.,Proofs of the thermal reduction of graphene oxide into graphene/热还原的证据,Conductivity of GO and grpahene电导率,sp3 Csp2 C,The EMI SE of GO and graphene屏蔽效能,B.Shen,W.T.Zhai*et al.,Carbon,2016,102,154.,Preparation of graphene
18、foam by the hydrazine foaming/水合肼发泡制备石墨烯泡沫,The generated CO2 and H2O gas during chemical reduction was used for expansion/化学还原过程中产于的气体用于发泡,Comparison of the EMI SE of graphene foam and film in broadband range/屏蔽效能,8.2-59.6 GHz including X-band,Ku-band,K-band,Ka-band,and U-band,The possible mechanism
19、/可能的机理,37,Conclusions/结论,Lightweight graphene nanocomposites foams such as PEI/graphene,PI/graphene,carbon/graphene,graphene foams had been fabricated in this study;采用相分离的方法，制备了含有高含量的PEI/PEI复合泡沫 The bubble structure enhanced the multi-reflection of EM wave,increased the absorptivity and thus the SEA;泡孔结构加强了对电磁波的多次发射，增加了材料对电磁波的吸收；Graphene foam with thickness of 15 m exhibited high SE of 25 dB within 8-60GHZ.全碳/石墨烯泡沫具有优异的宽频电磁波屏蔽效能,38,Thank you for your attention,
