Citethis:NewCarbonMaterials,2024,39(2):271-282DOI:10.1016/S1872-5805(24)60835-8Polyimide-assistedfabricationofhighlyorientedgraphene-basedall-carbonfoamsforincreasingthethermalconductivityofpolymercompositesXIONGKe1,SUNZhi-peng1,HUJi-chen1,MACheng1,WANGJi-tong1,*,GEXiang2,QIAOWen-ming1,*,LINGLi-cheng1（1.StateKeyLaboratoryofChemicalEngineering,EastChinaUniversityofScienceandTechnology,Shanghai200237,China;2.ChangzhouFuxiTechnologyCo,Ltd.,Changzhou213144,China）Abstract：Grapheneanditsderivativesareoftenpreferentiallyorientedhorizontallyduringprocessingbecauseoftheirtwo-di-mensional(2D)layerstructure.Asaresult,thermalinterfacematerials(TIMs)composedofapolymermatrixandgraphene-derivedfillersoftenhaveahighin-plane(IP)thermalconductivity(K),however,thelowthrough-plane(TP)Kmakesthemunsuitableforpracticaluse.Wereportthedevelopmentofhigh-qualitypolyimide/graphitenanosheets(PG)perpendiculartotheplaneusingadir-ectionalfreezingtechniquethatincreasetheTPKofpolymer-basedcomposites.Graphene-derivednanosheets(GNs)wereobtainedbythecrushingofscrapsofhighlythermallyconductivegraphenefilms.Awater-solublepolyamicacidsaltsolutionwasusedtodis-persethehydrophobicGNsfillertoachievedirectionalfreezing.Thepolyimide,whichfacilitatedthedirectionalalignmentoftheGNs,wasthengraphitized.TheintroductionoftheGNsincreasestheorderanddensityofthePG,thusimprovingthestrengthandheattransferperformanceofitspolydimethylsiloxane(PDMS)composite.TheobtainedPG/PDMScomposite(21.1%PG,massfrac-tion)hasanimpressiveTPKof14.56W·m−1·K−1,81timesthatofpurePDMS.Thissimplepolyimide-assisted2DhydrophobicfillersalignmentmethodprovidesideasforthewidespreadfabricationofanisotropicTIMsandenablesthereuseofscrapsofgraphenefilms.Keywords:Graphenefilm；Reutilization；Thermalconductivity；Anisotropicfoam；Thermalinterfacematerials1IntroductionTheperformanceofintegratedcircuitsoftende-gradessignificantlyorfailstooperateduetooverheat-ing.Consequently,effectivethermalmanagementma-terialsarevitalfortheoptimaloperationofhigh-pow...
