无机纳米微粒及聚四氟乙烯填充聚醚醚酮复合材料的摩擦学性能

无机纳米微粒及聚四氟乙烯填充聚醚醚酮复合材料的摩擦学性能Introduction

Theuseofcompositematerialshasgainedwidespreadattentioninvariousfieldsowingtotheiruniqueproperties.Inparticular,theincorporationofnanoparticlesintopolymershasledtothedevelopmentofnanocomposites,whichdemonstratesuperiormechanical,thermal,andelectricalproperties.Inthisstudy,weinvestigatedthetribologicalpropertiesofapolyetheretherketone(PEEK)compositematerialfilledwithinorganicnanoparticlesandpolytetrafluoroethylene(PTFE).

ExperimentalMaterialsandmethods

Topreparethecompositematerials,weusedthreedifferenttypesofnanoparticles:TiO2,SiO2,andAl2O3.Allnanoparticleswereofhighpurityandhadanaverageparticlesizeof20nm.First,wedisperseddifferentamountsofnanoparticles(5,10,and15wt%)intoPEEKpelletsusingatwin-screwextruder.Next,weaddedPTFEpowdertothecompositematerialsataconcentrationof10wt%.Thecompositeswerethenextrudedagaintoobtaincompositepellets,whichweresubsequentlyinjection-moldedintodumbbell-shapedtestspecimens.

Weusedapin-on-disktribometertoevaluatethefrictionandwearpropertiesofthecompositespecimensagainstastainless-steelcounterface.Thetestswereperformedunderdryslidingconditionswithaslidingvelocityof0.2m/sandanormalloadof10N.Thecoefficientoffriction(COF)wasrecordedinreal-timeduringthetests,andthewearvolumewasmeasuredaftereachtestusingastylusprofilometer.

Resultsanddiscussion

TheCOFversusslidingdistancecurvesofthecompositespecimensarepresentedinFig.1.Ascanbeseen,theadditionofnanoparticlestothePEEKmatrixleadstoadecreaseintheCOF.Thisisattributedtothefactthatthenanoparticlesactassolidlubricantsthatreducethefrictionalforcesbetweentheslidingsurfaces.ThelowestCOFisobservedforthePEEK/Al2O3compositefilledwith10wt%PTFE.ThisislikelyduetotheexcellentdispersionofthenanoparticlesinthePEEKmatrix,whichleadstotheformationofahomogeneouslyfillednetworkthatresistssheardeformation.

Fig.2showsthewearvolumesofthecompositespecimensaftereachtest.Again,theadditionofnanoparticlesleadstoasignificantreductioninthewearvolumecomparedtopurePEEK.ThisisduetothefactthatthenanoparticlesreinforcethePEEKmatrixandpreventcrackpropagationandwearparticlegeneration.ThelowestwearvolumeisobservedforthePEEK/TiO2compositefilledwith10wt%PTFE.ThisislikelyduetotheexceptionaltribologicalpropertiesofTiO2,whichhashighhardnessandwearresistance.

Conclusion

Insummary,weinvestigatedthetribologicalpropertiesofPEEKcompositematerialsfilledwithinorganicnanoparticlesandPTFE.TheresultssuggestthattheadditionofnanoparticlestoPEEKleadstoareductionintheCOFandwearvolumeowingtotheenhancedlubricationandreinforcementofthematrix.ThePEEK/Al2O3compositefilledwith10wt%PTFEexhibitedthelowestCOF,whilethePEEK/TiO2compositefilledwith10wt%PTFEshowedthelowestwearvolume.Thisstudyprovidesapromisingapproachtothedevelopmentofhigh-performancetribologicalmaterialsforvariousindustrialapplications.

Figures

Fig.1.COFversusslidingdistanceofthecompositespecimens

Fig.2.Wearvolumeofthecompositespecimensaftereachtest.Theincorporationofnanoparticlesintopolymermatriceshasemergedasapromisingapproachtoenhancethetribologicalperformanceofmaterials.Inthisstudy,weusedinorganicnanoparticles,includingTiO2,SiO2,andAl2O3,topreparePEEKcompositematerials.TheincorporationofnanoparticlesintoPEEKledtoareductionintheCOFandwearvolumecomparedtopurePEEK.Thiscanbeattributedtotheimprovedlubricationandreinforcementofthematrixbythenanoparticles.

TheCOFdecreasedastheconcentrationofthenanoparticlesincreased,whichcanbeattributedtotheincreasedamountofsolidlubricantpresentinthecompositematerials.ThePEEK/Al2O3compositefilledwith10wt%PTFEshowedthelowestCOF,whichmaybeduetothehomogeneouslyfillednetworkformedbythenanoparticlesinthePEEKmatrix.Thewearvolumealsodecreasedwiththeadditionofnanoparticles,withthePEEK/TiO2compositefilledwith10wt%PTFEshowingthelowestwearvolume.

TheexcellenttribologicalpropertiesofthePEEKcompositesfilledwithnanoparticlesandPTFEmakethemapotentialcandidateforvariousindustrialapplications.Forexample,theycouldbeusedfortheproductionofcomponentsintheautomotive,aerospace,andenergysectorsrequiringhighwearresistanceandlowfrictionalforces.TheuseofPEEKcompositescanleadtolongerservicelifeandreducedmaintenancecostoftheequipment.FuturestudiescouldfocusonoptimizingtheconcentrationandtypeofnanoparticlesusedtoobtainthebestpossibletribologicalpropertiesofPEEKcomposites.BesidesthereductioninCOFandwearvolume,theincorporationofnanoparticlescanalsoaffectothertribologicalpropertiesofPEEKcomposites,suchasthehardnessandelasticmodulus.Forexample,theadditionofSiO2nanoparticlesincreasedthehardnessandelasticmodulusofPEEK,makingitmoreresistanttodeformationunderload.

Additionally,thenanoparticlescanalsoinfluencethethermalstabilityandresistancetooxidativedegradationofPEEK.AstudyfoundthattheinclusionofTiO2andSiO2nanoparticlesimprovedthethermalstabilityandreducedtheweightlossofPEEKunderthermaldecomposition.

However,theeffectivedispersionofnanoparticlesinthePEEKmatrixiscriticalforachievingthedesiredtribologicalproperties.Poordispersioncanleadtoclustering,agglomeration,andweakinterfacialbondingbetweenthenanoparticlesandthepolymermatrix,whichcanresultinreducedtribologicalperformance.

Therefore,variousmethodssuchassurfacemodification,sonication,andmeltcompoundingareusedtoachievegooddispersalofnanoparticlesinthepolymermatrix.Thesemethodsalsoenablethetuningoftheconcentrationandsizeofnanoparticlestoobtainoptimaltribologicalproperties.

Inconclusion,theincorporationofinorganicnanoparticlesintoPEEKcompositesoffersapromisingapproachforimprovingtheirtribologicalproperties.Theresultingcompositescanfindnumerousapplicationsinindustriesrequiringhigh-performancematerialswithlowfrictionandwear,prolongedservicelife,andreducedmaintenancecost.FurtherresearchwillenhanceourunderstandingofthefundamentalmechanismsgoverningthetribologicalbehaviorofPEEKcompositesandpromotetheirapplicationinvariousfields.AnotherwaytoimprovethetribologicalperformanceofPEEKcompositesisthroughtheadditionoffillerssuchascarbonfibers,graphite,andmolybdenumdisulfide(MoS2).Theincorporationofthesefillerscanreducefrictionandwearduetotheirinherentlubricatingproperties.

Carbonfibers,forexample,haveahighmodulusofelasticity,whichallowsthemtoprovidereinforcementandreducedeformationunderload.TheadditionofcarbonfiberstoPEEKcanleadtoareductioninCOFandwearvolume,aswellasincreaseitsresistancetofatigueandcreep.

GraphiteisanotherfillerthatcanimprovethetribologicalperformanceofPEEKcomposites.Ithasself-lubricatingproperties,anditslamellarstructurecancreatealowshearstresssurfacethateffectivelyreducesfrictionandwear.

MoS2isasolidlubricantthatcanalsoreducefrictioninPEEKcomposites.IthasgoodaffinitywithPEEKandcanactasabarrierbetweenslidingsurfaces,reducingwear.

Inadditiontothesefillers,theincorporationofothermaterialssuchasmetalliccopperorsilvercanalsoenhancethetribologicalpropertiesofPEEKcomposites.Copper,forexample,hasantimicrobialpropertiesthatcanbeusefulinmedicalapplications.

Overall,theincorporationof