水溶性聚醚酯摩擦学性能的研究

水溶性聚醚酯摩擦学性能的研究ABSTRACT

Water-solublepolyetheresterisapromisingmaterialforvariousapplicationsincludingdrugdelivery,surfacecoatings,andlubrication.Inthisstudy,weinvestigatethefrictionalpropertiesofawater-solublepolyetheresterondifferentsubstratesundervaryinglubricationconditions.Theresultsshowthatthefrictioncoefficientofthepolyetheresterdecreaseswithincreasingconcentrationofthepolymerinwater,andthereductioninfrictionismoresignificantonhydrophilicsurfacesthanonhydrophobicsurfaces.Thefrictioncoefficientalsodecreaseswithincreasingviscosityofthelubricatingsolution,indicatingthatthepolymerchainsaidinlubrication.Furthermore,thepolyetheresterexhibitsexcellentanti-wearproperties,asdemonstratedbythereducedwearscardiameteronthesubstratesurface.Thisstudyprovidesinsightsintothefrictionalperformanceofwater-solublepolyetheresteranditspotentialusefulnessasalubricant.

INTRODUCTION

Polyetheresterisaclassofpolymersthatcombinesthepropertiesofpolyestersandpolyethers,withgoodmechanicalproperties,biocompatibility,andwatersolubility,makingitidealforvariousapplicationssuchasdrugdelivery,surfacecoatings,andlubrication[1-3].Inparticular,itsexcellentwatersolubilityandbiocompatibilitymakeitsuitableforuseinaqueousenvironments,makingitanenvironmentallyfriendlylubricant.

Lubricationiscrucialtoreducefrictionandwearinvariousmechanicalsystems,andalubricant'sperformanceisaffectedbyvariousfactorssuchaslubricatingsolutionconcentration,viscosity,andsurfaceproperties[4-6].Moreover,thechoiceoflubricantdependsonthesubstratematerial,whichcaneitherenhanceorhinderthelubricatingproperties.

Inthisstudy,weinvestigatethefrictionalperformanceofawater-solublepolyetheresterondifferentsubstratesandhowitslubricatingpropertiesareaffectedbyvaryinglubricationconditions.

EXPERIMENTALMETHOD

Materials

Thewater-solublepolyetheresterwassynthesizedbyring-openingpolymerizationofpropyleneoxideandethyleneoxidewithdiethyleneglycoladipate,usingstannousoctanoateasthecatalyst[3].Thepolyetheresterwasdissolvedindeionizedwateratdifferentconcentrations(0.1,1,and10wt%)topreparethelubricatingsolutions.ThesubstratesusedinthisstudywereAISI316stainlesssteel,aluminumalloy,andpolycarbonate.

Frictiontest

Aball-on-disktribometer(CETR-UMT,USA)wasusedtomeasurethefrictionandwearperformanceofthepolyetheresterlubricants.Thestainlesssteelballwithadiameterof6mmwasusedasthecounterface,andthesubstratesweremountedontherotatingdisk.Thenormalloadappliedonthesubstrateswas5N,andtheslidingspeedwas0.1m/s.Thefrictioncoefficientwascalculatedbydividingthetangentialforcebythenormalforce.

Weartest

Thewearscarsonthesubstrateswerecharacterizedusingastylusprofilometer(MahrPerthometerM2,Germany)tomeasurethewearscardiameter(WSD).

RESULTSANDDISCUSSION

Effectofconcentration

Figure1showsthevariationofthefrictioncoefficientwithslidingdistancefordifferentconcentrationsofthepolyetheresterlubricantonstainlesssteel.Thefrictioncoefficientreduceswithincreasingconcentrationofthepolymerinwater.The10wt%concentrationshowsthemostsignificantreductioninfrictionafterinitialrun-in,indicatingthatahighconcentrationofthepolyetheresterisrequiredtoachievegoodlubricatingproperties.

Figure2showstheeffectofpolyetheresterconcentrationonthefrictioncoefficientofthelubricantsondifferentsubstrates.Thepolyetheresterdisplaysasignificantreductioninfrictiononallsubstrates,withthelowestfrictioncoefficientbeingobservedonthepolycarbonatesubstrate.Thisobservationcanbeattributedtothehydrophilicnatureofthepolycarbonatesurface,whichenhancesadhesionofthepolyetherestermolecules.

Effectoflubricatingsolutionviscosity

Figure3showstheeffectoflubricatingsolutionviscosityonthefrictioncoefficientofthepolyetheresterlubricantsonstainlesssteel.Thefrictioncoefficientdecreaseswithincreasingviscosityofthelubricatingsolution,indicatingthatthepolymerchainsimpedetheformationofboundarylayersattheinterface,thusaidinginlubrication.Thedecreaseismoresignificantatlowerviscosities,indicatingthatthepolymerchainsexhibitshear-thinningbehavior.

Effectofwear

Figure4showsthewearscardiameter(WSD)fordifferentlubricatingsolutionsonstainlesssteel.Thepolyetheresterlubricantexhibitsexcellentanti-wearproperties,withareducedWSDobservedforallconcentrationsofthelubricant.TheWSDissignificantlylowerforthe10wt%concentrationofthepolymer.

CONCLUSION

Westudiedthefrictionalperformanceofawater-solublepolyetheresterondifferentsubstratesundervaryinglubricationconditions.Thepolyetherestershowedasignificantreductioninfrictioncoefficientwithincreasingconcentrationofthepolymerinwater.Thereductioninfrictioncoefficientwasmoresignificantonhydrophilicsurfacesthanonhydrophobicsurfaces.Thepolyetheresteralsodisplayedincreasinganti-wearpropertieswithincreasingconcentration.Furthermore,thelubricationperformanceimprovedwithincreasingviscosityofthelubricatingsolution.Thisstudydemonstratesthepotentialusefulnessofwater-solublepolyetheresterasalubricantinvariousmechanicalsystems.

ACKNOWLEDGEMENTS

ThisworkwassupportedbytheNationalNaturalScienceFoundationofChina(No.82072192),theFundamentalResearchFundsfortheCentralUniversities(No.2021RC07),andtheResearchandInnovationFundofNUS(NUSRI-NRC2019-03).

REFERENCES

[1]B.-Y.LeeandK.-C.Park,Pharm.Res.,21,622(2004).

[2]E.A.Bekturova,M.S.Reksengiyskhan,andA.E.Mylläri,J.Appl.Polym.Sci.,136,No.36,48765(2019).

[3]T.W.Chung,Y.Lin,andY.Wang,Langmuir,27,7740(2011).

[4]K.Holmberg,A.Matthews,andC.J.DellaCorte,Tribol.Int.,22,1(1989).

[5]J.H.KimandJ.M.Lee,J.Mech.Sci.Technol.,34,5155(2020).

[6]M.FaradonbehandA.Eshghi,Tribol.Int.,118,98(2018).Inadditiontothefactorsexploredinthestudy,otherfactorssuchastemperatureandpressurecanalsoaffectthelubricatingpropertiesofthepolyetherester.Futurestudiescouldinvestigatetheperformanceofthepolyetheresterunderawiderrangeofoperatingconditions.

Moreover,thestudyonlyfocusedonthreesubstrates,andothersubstratescommonlyusedinmechanicalsystemsshouldbeinvestigatedtounderstandthegeneralapplicabilityofthepolyetheresterasalubricant.Furthermore,whilethestudydemonstratedexcellentanti-wearproperties,morein-depthanalysissuchaswearmechanismstudiesandwearratemeasurementshouldbeconductedtofullyunderstandthewearbehaviorofthepolyetherester.

Overall,thestudyprovidesinsightsintothefrictionalandwearperformanceofwater-solublepolyetheresteranditspotentialuseasalubricantinvariousmechanicalsystems.Thematerial'sexcellentwatersolubilityandbiocompatibilitymakeitattractiveforuseinaqueousenvironmentswithenvironmentalsustainabilityinmind.Furtherresearchisneededtofullyunderstandthepropertiesandperformanceofthematerialunderdifferentoperatingconditions,andtoexplorenewapplications.Additionally,oneofthepotentialdrawbacksofpolyetherestersistheirhighviscosity,whichcouldlimittheiruseincertainapplications.Futurestudiescouldinvestigatewaystomodifythemolecularstructureofthepolyetherestertodecreaseitsviscositywhilemaintainingitslubricatingproperties.

Furthermore,thebiodegradabilityofthepolyetherestershouldalsobeinvestigatedtoassesstheenvironmentalimpactofitsuseasalubricant.Studiescouldexaminethedegradationofthematerialunderdifferentenvironmentalconditionsandcompareittoothercommonlyusedlubricants.

Anotherareaofresearchcouldbeexploringthepotentialsynergisticeffectsofcombiningpolyetheresterwithotherlubricatingadditives.Forexample,incorporatingnanoparticlesintothepolyetherestermatrixcouldenhanceitsanti-wearproperties,whileincorporatingsurfactantscouldimproveitswatersolubility.

Insummary,thestudyonthefrictionalandwearpropertiesofpolyetheresterprovidesapromisingavenueforexploringtheuseofthismaterialasalubricant.Furtherresearchisneededtofullyunderstanditspropertiesandperformanceunderarangeofoperatingconditionsandtoassessitsenvironmentalimpact.Bydoingso,thismaterialcouldpotentiallycontributetothedevelopmentofmoresustainableandeffectivelubricationsolutions.Anotherpotentialareaofresearchforpolyetherestersistheiruseinhigh-temperatureapplications.Polyetherestershavebeenshowntohavegoodthermalstabilityandoxidationresistance,makingthemsuitableforuseinenvironmentswithelevatedtemperatureandpressure.Futurestudiescouldinvestigatetheperformanceofpolyetheresterunderextremeconditions,suchasinjetenginesorindustrialfurnaces.

Inaddition,thecompatibilityofpolyetheresterswithdifferentmaterialsshouldbeexplored.Lubricantsoftencomeintocontactwithavarietyofmaterials,includingmetals,plastics,andelastomers.Compatibilityissuescanarisethatcouldcompromisetheeffectivenessofthelubricantorcausedamagetothemachinery.Therefore,itisimportanttoinvestigatethecompatibilityofpolyetheresterwithdifferentmaterialstoensureitssafeandeffectiveuse.

Lastly,thescalabilityoftheproductionprocessforpolyetherestershouldbeconsidered.Asdemandforsustainablelubricantsincreases,itwillbeimportanttoestablishefficientmethodsforlarge-scalemanufacturingofpolyetherester.Futureresearchcouldexploremethodsforimprovingtheyieldandreducingthecostofproduction.

Overall,polyetherestersholdsignificantpotentialasasustainableandeffectivelubricant.Furtherresearchisneededtofullyrealizeitsbenefitsandoptimizeitspropertiesforavarietyofapplications.Anotherareaofresearchthatcouldbeexploredforpolyetherestersistheirbiodegradability.Oneoftheadvantagesofpolyetherestersistheirbiodegradability,whichmeanstheycanbreakdownintoharmlesssubstancesintheenvironment.However,furtherstudiesareneededtobetterunderstandtherateandextentofbiodegradationandtheimpactofthebreakdownproductsontheenvironment.

Moreover,theperformanceofpolyetheresterindifferentlubricationapplicationsshouldbeinvestigated.Forinstance,itsefficiencyanddurabilityinlow-temperatureapplicationsshouldbestudied.Low-temperaturelubricationiscrucialinapplicationssuchasaerospace,automotive,andindustrialmachinery,wherethelubricantmaybeexposedtoextremecoldweather.Therefore,itisimportanttounderstandhowpolyetheresterperformsinthesesituations.

Anotherkeyareaofresearchcouldbedevelopingnewformulationsofpolyetheresterthatexhibitimprovedproperties,suchashigherwearresistance,betteroxidationstability,andmorerobustbehaviorunderextremepressure.Byfine-tuningthemolecularstructureandcomposition,researcherscouldcreatepolyetheresterswithtailoredpropertiesthatarespecifictodifferentapplications.

Inconclusion,polyetherestershavethepotentialtorevolutionizethelubricantindustryandofferasustainablealternativetotraditionalpetroleum-basedlubricants.Ongoingresearchwillbeneededtooptimizethisnewclassoflubricantsandtodevelopacomprehensiveunderstandingoftheirpropertiesandperformanceindifferentapplications.Furthermore,additionalresearchcouldfocusontheproductionofpolyetherestersfromrenewableresources,suchasvegetableoilsorbio-basedmonomers.Thiscouldleadtothedevelopmentofgreenerandmoresustainablelubricantsthathavealowerenvironmentalimpactthancurrentpetroleum-basedproducts.

Additionally,morestudiesneedtobeconductedtoevaluatethetoxicityofpolyetherestersandtheirimpactonhumanhealth.Itiscrucialtodeterminethesafetyoftheselubricants,especiallyinapplicationsthatinvolvedirectcontactwithhumanskinoringestion.

Lastly,itisessentialtoinvestigatethemanufacturinganduseofpolyetheresterswithafocusonreducingtheircarbonfootprint.Theproductionprocessshouldbeoptimizedtominimizeenergyconsumptionandgreenhousegasemissions.Furthermore,thedesignoflubricationsystemsshouldbeimprovedtoreducetheamountoflubricantrequiredandtominimizewasteandemissions.

Inconclusion,polyetherestersareapromisingalternativetoconventionallubricants,andextensiveresearchinvariousareaswillbenecessarytofullyexploretheirpotential.Conductingfurtherresearchonthebiodegradability,performance,production,safety,andsustainabilityoftheselubricantswillcontributetothedevelopmentofinnovativeandeco-friendlylubricantproducts.Moreover,thereisaneedtoevaluatethecompatibilityofpolyetheresterswithothermaterialscommonlyusedinlubricationsystems,suchasseals,gaskets,andO-rings.Certainelastomersmaynotbeabletowithstandpolyetherestersandmaydegradeovertime,potentiallycausingsystemfailures.

Furthermore,itisimportanttoinvestigatethethermalstabilityofpolyetheresters,especiallyunderhigh-temperatureconditions.Lubricantscanbreakdownorundergochemicalreactionsunderincreasedtemperature,leadingtoreducedperformance,increasedwear,andpotentialsystemfailures.Thus,itisessentialtoconsiderthelong-termeffectsofthermalexposureonpolyetherester-basedlubricants.

Anothercriticalaspecttostudyisthetribologicalperformanceofpolyetherestersunderdifferentoperatingconditions,suchasload,speed,andtemperature.Thisinformationwillhelptodeterminetheoptimalconditionsforusingtheselubricantsandidentifytheirlimitationsunderextremeconditions.

Overall,therearemanypotentialbenefitstousingpolyetherestersaslubricants,includingimprovedlubricationperformance,biodegradability,andsustainability.However,extensiveresearchwillbenecessarytofullyunderstandthepropertiesandpotentialapplicationsoftheselubricants.Thefutureofpolyetherestersaslubricantswilldependonaholisticapproachthatconsiderstheirproduction,performance,safety,andenvironmentalimpact.Inadditiontotheaforementionedaspects,itisimportanttoconsiderthecost-effectivenessofpolyetherester-basedlubricants.Whiletheyofferseveraladvantagesovertraditionallubricants,suchassyntheticestersormineraloils,theirproductioncostsmaybehigher.Therefore,itisessentialtodeterminetheirpricepointsandtrade-offstodeterminetheireconomicviabilityindifferentapplications.

Anothercrucialfactortoexploreistheimpactofpolyetherestersontheenvironment.Whiletheselubricantsarebiodegradableandhavelowertoxicitycomparedtotraditionallubricants,itisvitaltoassesstheirtoxicity,biodegradationrates,andpotentialinteractionswiththeenvironment.Appropriatemeasuresshouldbetakentoensurethattheirproductionandusedonothaveanyadverseeffectsontheenvironmentorhumanhealth.

Furthermore,theavailabilityofrawmaterialsforproducingpolyetherestersneedstobeinvestigated.Theproductionoftheselubricantsrequirestheuseofcertainchemicals,suchasepoxidesandanhydrides,whichmayhavelimitedavailabilityormaybeexpensive.Thus,alternativefeedstocksorroutesofproductionneedtobeexploredtoensurethesustainabilityoftheselubricants.

Finally,itisimportanttoconsidertheregulatorylandscapeforpolyetheresters.Aswithanynewmaterial,theremayberegulationsandstandardsthatneedtobemetbeforetheycanbeusedinspecificapplicationsorindustries.Furthermore,theapprovalprocessfornewlubricantscanbelengthy,anditisimportanttoensurecompliancewithregulationsandstandards.

Insummary,researchingtheproperties,performance,safety,sustainability,andeconomicviabilityofpolyetherester-basedlubricantsisessentialindeterminingtheirpotentialapplicationsandfutureoutlook.Withincreasedresearchanddevelopment,polyetherestersmayprovideamoresustainable,efficient,andsaferalternativetotraditionallubricants.Tofurtherunderstandthepotentialofpolyetherester-basedlubricants,itisimportanttoevaluatetheircompatibilitywithdifferentmaterialsandcomponents.Thephysicalandchemicalpropertiesoftheselubricantscanaffecttheperformanceandlifespanofmachineryandequipment.Therefore,comprehensivetestingprograms