The Preparation And Properties Of Excellent Thermally Conducting Poly(Pheny Sulfone) Composites For High Electromagnetic Interference Effectiveness

With the advent of the fifth generation mobile communication technology,electronic devices are moving in the direction of miniaturization,lighter and thinner,high-speed and highly integration,which makes electronic products'power consumption continue to increase and heat dissipation difficult,seriously limiting the development of the next generation of novel electronic devices.As electromagnetic radiation pollution has become increasingly prominent problem,it could reduce the lifespan of sensitive electronic components and even endanger human's health.However,traditional thermal conductive(TC)and electromagnetic shielding(EMI)materials,such as aluminum foil and copper foil,cannot meet the requirements of modern communication,intelligent electronic equipment,automobile and consumer electronics due to their high density and poor corrosion resistance.On the contrast,polymer materials are widely utilized in the field of industry,microelectronics,energy,aerospace because of their lightweight,chemical corrosion resistance,impact resistance,heat fatigue resistance and easy processing.Nevertheless,polymer materials are poor conductors of electricity and heat flow,so their thermal and electrical conductivity as well as electromagnetic shielding performance are generally low,which largely restricts their applications in the field of heat conduction and dissipation,along with electromagnetic interference.Up to now,the most common method to prepare thermal conductive materials at home and abroad is to blend high thermal conductive materials,such as graphene,Mxene,boron nitride,with polymer resin matrix to form a continuous and effective thermal conductive network inside the matrix,so as to achieve excellent heat conduction and electrical conductivity.Based on the S.A.Schelkunoff's plane electromagnetic wave conduction theory,perfect conductive network structure are one of prerequisites to obtain high EC value and electromagnetic shielding effectiveness.In this paper,we mainly focus on the surface modification of graphene via non-covalent approach and discuss synergetic effects of multifunctional fillers.The main research content can be divided into two parts as follow.Firstly,nickel particles were deposited on the graphite nanoplatelets'surface of to fabricate highly conductive Gn Ps@Ni core-shell structure hybrid fillers via electroplating.The modified Gn Ps were blending with poly(pheny sulfone)via solution blending method,followed by hot-pressing method to achieve high thermally conducting Gn Ps@Ni/PPSU composites for high performance electromagnetic interference effectiveness.The results showed that in plane and through plane thermal conductivity of the composite could reach 2.6 Wm^-1k^-1 out of plane and 3.7 Wm^-1k^-1,respectively,at the 40 wt%filler loading,which were 9.4 and 20 times higher than that of pure PPSU resin.The fillers'orientation degree was discussed by XRD and SEM.Then heat conduction data were fitted and analyzed by Agari models,and the heat conduction mechanism was further explored.The testing results also demonstrated that the material exhibited good conductivity,electromagnetic shielding effectiveness and superior thermal stability.Overall,it is a high thermal conductivity and electromagnetic shielding material at high temperatures.In the current study,graphite nanoplatelets were functionalized by polydopamine,and then compounded with multi walled carbon nanotubes to achieve a good dispersion hybrid filler(Gn Ps@PDA-MWCNTs).The hybrid fillers were mixed with poly(phenysulfone)via solution blending.Then the developed composites were prepared by simple hot pressing process.It was found that the in-plane thermal conductivity and out of plane thermal conductivity of the composite were 3.7 Wm^-1k^-1and 5.4 Wm^-1k^-1,individually,when the filling fraction was 17.6 vol%,indicating a dramatic increment of 2060%and 1410%compared to the pure PPSU.The MWCNTs can bridge with the adjacent Gn Ps,leading to the establishment of highly dense and continuous heat conductive pathways.The surface free energy of the modified nano graphite nanoplatelets was reduced after treatment with polydopamine,which helped to improve the dispersion of the fillers and interfacial adhesion with the polymer matrix,and then reduce the interfacial thermal resistance.The materials showed excellent electrical conductivity,and the maximum EMI SE was up to 62.9 d B.At high temperature,it had lower coefficient of thermal expansion(CTE),higher glass transition temperature(Tg)and thermal decomposition temperature(TGA).