Preparation And Experiment Of Nanocarbon /Polymer-based Thermal Conductive Composites

With the rapid development of information industry, the integration and miniaturization of electronic components has been considerable development. The electronic components’ heatdissipation problem become more and more important no matter own to its work efficiency, reliability, lifetime, also own to its miniaturization and micromation, So the materials with high thermal conductivity are needed. And that Polymer materials which have highly thermal conductivity can solve the problem of heat dissipation of electronic components and improve its stability and prolong its life, and can well apply in some certain specific areas. Therefore, the study on thermal conductive polymer materials becomes very important.By taking the high thermal conductivie polymer materials as the research object, this thesis made innovative research on the carbon-coated copper nanoparticles, multilayer graphite, carbon-nanotube as well as the high thermal conductive polymer composites. Carbon-coated copper nanoparticles were synthesized innovatively by means of arc discharge method, The structure and phase of carbon coated copper nanoparticles were examined. At the same time, Thermal conductive silicone resin composites were prepared by using mixing method, adopting carbon-coated copper nanoparticles, MWNT, A1N and SiC as thermal conductive fillers and fillers were dispersed in silicone resin. And also thermal conductive plastic composites were prepared by using machinery method, adopting multilayer graphite, graphite as thermal conductive fillers and fillers were dispersed in polyethylene, polyethylene grafting maleic anhydride. The thermal conductivity, mechanical property, thermal Stability, thermal expansibility, electrical resistivity of thermal conductive composites have researched.Carbon-coated copper nanoparticles were synthesized by carbon arc discharge method using copper and carbon powder as raw material, in which the copper powder content are 20%. The structure of sample was characterized by X-ray diffraction(XRD), and the Topography, size distribution, phase composition and ant oxidation property of the nanoparticles were analyzed and tested by transmission electron microscopy(TEM) and scanning electron microscopy (SEM). The results indicated that Carbon-coated copper nanoparticles are clear core-shell structure, the core of the particles is copper, and shell of the particles is graphite carbon layers. Effect of Carbon package is better, particle reunion without apparent.The thermal conductive silicone resin slurry were prepared by using the silicone resin as base material and carbon-coated copper nanoparticles, aluminum nitride, carborundum as fillers. Dipping coating When the consistency of silicone resin slurry is 30%. And after solvent volatilize we can made flexible thermal conductive silicon resin patch which with glass fiber cloth, barbed wire as a support structure. The thermal conductivity of thermal patch increased with the increasing fillers loading, and the thermal conductivity of thermal patch instead decline when fillers loading increases to certain degree. The data show that thermal effect of nano AlN is better than nano SiC. carbon-coated copper nanoparticles.The thermal conductive silicone resin composites were prepared by using ball millmixing method and using the silicone resin as base material and multilayer graphite, MWNT as fillers. The conductive fillers were uniformly dispersed in the silicone resin matrix. The conductive filler particles mutual connected and formed conductivity networks when fillers reached to a certain extent. The thermal conductivity of multilayer graphite/silicone resin increased with the increasing fillers loading, and the thermal conductivity of multilayer graphite/silicone resin instead decline when fillers loading increases to certain degree. The thermal conductivity of graphite/silicone resin higer than AIN/silicone resin, SiC/silicone resin. When the filling loading of multilayer higer reached 45%, the thermal conductivity of composite reached 2.26 W/m-k, while the highest thermal conductivity of the composites filled with AlN, SiC, were 0.64 W/rn·k,0.445 W/m-k, while the thermal conductivity of silicone resin/MWNT reach 2.58 W/mk when filling loading of MWNTreached 45%. the thermal conductivity of composites increased by 2568%,506%, 727%,2931% respectively relative to blank silicone resin. The addition of fillers into the silicon resin could improve the thermal stability of the silicon resin and delay the oxidation onset temperature.The thermal conductive plastic composites were prepared by using machinery mixing method and using thePE, GPE as base material and multilayer graphite, graphite as fillers.In the same processing conditions, different kinds of conductive fillers filled PE, GPE affected the thermal conductivity, mechanical properties and thermal stability. The results showed that tensile strength and elongation at break of the composites decreased with increasing filler amount,100% modulus, hardness and the thermal conductivity raised with increasing filler content. In the same filler content, the thermal conductivity of multilayer graphite/PE was better than that of graphite/PE, multilayer graphite/GPE. graphite/GPE. When filling loading reach 300%, the thermal conductivity of multilayer graphite/PE. graphite/PE, multilayer graphite/GPE and graphite/GPE were 14.31 W/m-k,6.72 W/m-k,6.50 W/m-k and 5.98 W/m-k respectively. The thermal conductivity increased by 4710%,436%,2166%, 2167%,1929% respectively relative to blank PE and GPE. The thermal stability of composites was better than that of pure PE, GPE.