Preparation and characterization of Electro conductive polymer composites.docx

Preparation and characterization of Electro conductive polymer composites.docx

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PreparationandcharacterizationofElectroconductivepolymercomposites

PreparationandcharacterizationofElectroconductivepolymercomposites

MaxRamosandMiaoYu1257747

AucklandUniversityofTechnology,Auckland,NZ

yyymmm_1988@

Abstract

Whilemostpolymersarethermallyandelectricallyinsulating,thosecontainingdispersedconductivefillershaverecentlyemergedonthemarket.Electricallyconductivecompositeshavefoundpotentialusesasanti-staticlayers,chemicalvaporssensors,andthermalresistorsbecauseoftheirelectricalandmechanicalabilities.Thebalancebetweentheelectricalandmechanicalpropertiesofthiscompositestillundergoeschallenges.Unfortunately,excessiveamountsofcarbonblackcanproducebrittlefilmsandtoolittlecarbonblackcanresultinlowconductivity.Highlyelectricallyconductiveepoxyresincompositeswerepreparedbymixingusingcarbonblackasconductingfillers.Theprimarymethodologiesusedonthisprojectincludeliteratureview,conductivefillerdispersionandcastingmethodforsamplemaking,usemicrocomputercontrolelectronuniversaltestingmachinetotestthemechanicalabilitiesofsampleanduseresistancetestertesttheelectricalconductivity,analysis.Thepercolationtheoryisusedtoexplaintherelationshipbetweenfillercontentandelectricalconductivity.Theaimoftheprojectisusingepoxyresinandcarbonblackasrawmaterialstoproduceconductivecompositeusingcarbonblackasconductivefillers,studyandexplorethemechanicalabilitiesandelectricalconductivityofconductivecomposite.Differentcarbonblackloadingwillbeusedtodeterminepercolationthreshold.

Kewwords:

conductivecomposite,epoxyresin,carbonblack,polymer.

1.Introduction

Overthepastfewdecades,withthedevelopmentofpolymercomposites,ithasattractedagreatattention.Alargenumberofresearcheshavebeendonetoproduceorganicmaterialswithgoodengineeringpropertieswhicharealsoelectricallyconductive[1].Inrecentyears,withthedevelopmentoffunctionalmaterials,polymercomposites,achievedsignificantsuccessinmanyapplicationareasuchasbatterycomponents,antistaticshields,circuitrycomponents,andelectromagneticradiationabsorbers[2][12].Sincethe1970s,ateamledbyVoetandKostfirststudiedtheforce-electricityperformanceofcarbonblackfilledrubber.Later,theresearchersanalyzedandreportedforce-electricityperformanceofcarbonblackfilledethylene,octene,tetrachloroethylenecopolymercompositematerials[2][3][4].Carbonblackasakindofnanoscaledimensionsparticles,duetothelargesurfacearea,surfaceenergyandirregularchainstructure,easytoaggregateinpolymer,greatlyinfluencetheperformanceofthecarbonblack-polymercomposites.Recently,theinfluenceofcarbonblack-polymercompositematerialsmechanicabilitiesandelectricallyconductiveabilitiesbycarbonblackdispersionhasbeenextensiveresearch.Forblackcarboncompositematerials,epoxyresin,onlyplayssupportingthecarrierrole,carbonblackplaysconductiverole.Carbonblackisakindofgranularindustrycarbon;particlediameterisbetween14nm-300nm.Itisakindofcommonfillingmaterial.Highconductivecarbonblackisakindofshellstructureofgraphite;theconstitutivepropertyisveryhigh,easilypenetratingtoeachotherstretchedintochains.Although,theparticlesarespherical,itsbasicstructureissimilartorandomdistributionoffiberconductionsystem,thevolumeresistivityisabout0.1Ω*cm-1Ω*cm.Theoretically,thesmallercarbonblackparticlesizeis,thegreaterthesurfacearea,thehighertheconstitutiveproperty,thehigherelectricalconductivityitis.However,consideringtheactualmachiningofcarbonblackfilledresin,inordertogetagoodelectricalconductivity,carbonblackparticlesizeshouldnotbetoosmall,constitutivepropertyshouldnotbetoohigh[4].

Epoxyresinsarecreatedbytransformingliquidpolyethersintoinfusiblesolidsthroughaspecialcuringprocess.Inmostcases,resinsaretheresultofachemicalreactionbetweenepichlorohydrinandbisphenol-A.Anepoxyresinisdefinedasamoleculewithmorethanoneepoxygroup,whichcanbehardenedintoausableplastic.Theepoxygroup,whichisalsocalledtheglycidylgroup,hasthroughitscharacteristicappearancegiventhenametoepoxy[14].

Epoxygroup:

Epoxyresinhasthecharacteristicsofexcellentcakingproperty,mechanicalpropertiesandcorrosionresistance;alsoeasytoprocessingmolding,lowcost;soitiswidelyusedinplastics,coatings,electricalmaterials,lampencapsulationmaterialsandadhesivesindustry[14].

Therehavebeenprimarilytwoapproachestoproducingconductiveorganicmaterials.Theseare:

1,Preparationofhighlyconjugatedpolymerssuchaspoly-acetyleneand2,Dispersionofconductivefillerparticlesintocommonpolymersandresins[15][16].

Carbonblack-Epoxyresincompositesisrepresentativeofthermosettingresinmatrixcomposite,becauseithasadvantagesofsimpleprocessing,goodheatresistanceandhighstability,canbewidelyusedinoptoelectronicdevices,electromagneticshielding,antistaticmaterialsandconductiveadhesive.

Inthisproject,thematerialsusesare105EPOXYRESIN,CARBONBLACKandZ296EPOXYHARDERER,throughthemethodofdispersingdifferentproportionsofcarbonblack,studyandanalyzehowcarbonblackinfluencethemechanicabilitiesandelectricallyconductiveabilitiesofcarbonblack-epoxyresinelectricallyconductivecomposites,preparedandgatherexperienceforfurtherstudies.

2.Experimentalprocedures

2.1Rawmaterialsprepare

Inthisprojectthematerialsuseare105EPOXYRESIN,CARBONBLACKandZ206EPOXYHARDERER.

Fig2.1105EPOXYRESIN

Fig2.2Z206EPOXYHARDERER

2.2Calculation

Inordertogetagoodresult,thecarbonblackcontentisdividedinto0%,0.1%,0.2%,1%,2%,and10%.Theweightofrawmaterialsis20gramsof105EPOXYRESINand10gramsofZ206EPOXYHARDERER.Forthisreason,calculatetheweightofcarbonblack.

0%:

0gramofcarbonblack.

0.1%:

0.03003gramofcarbonblack.

0.5%:

0.15075gramofcarbonblack.

1%:

0.30303gramofcarbonblack.

2%:

0.61224gramofcarbonblack.

10%:

3.33333gramofcarbonblack.

2.3Mixingandcasting

UsemetalmixermixingEPOXYRESINandCARBONBLACKinaglasscontainerforanhour.Then,addstheEPOXYHARDERER,usewoodsticksmixingthemforawhile.Thenputitintothemoldmakebywax,letittobecometheshapeweneed.

Fig2.3Waxmoldandthesample

Fig2.4Sample

2.4Mechanicalabilitiestest

Afterthesamplebecomehard,useVernierCaliperusetomeasurethethicknessandwidthofeachsample.Then,usemicrocomputercontrolelectronuniversaltestingmachinetogettheStrain-Forcecurveforeachsample.Force:

50000N,Testspeed:

3mm/min.

Fig2.5Testingmachine

Fig2.6Testingmachine

Fig2.7Testingmachine

Fig2.80%ofCarbonblack

Fig2.90.1%ofCarbonblack

Fig2.100.5%ofCarbonblack

Fig2.111%ofCarbonblack

Fig2.122%ofCarbonblack

Fig2.1310%ofCarbonblack

2.5Electricalconductivitytest

Useresistancetestertotesttheresistanceofeachsample.

3.Resultsanddiscussion

3.1Calculation.

AccordingtoEquation:

E=stress/strain,stress=F/A,strain=△L/L,and

Wt%

0%

0.1%

0.5%

1%

2%

10%

Width（m）

0.0064

0.0061

0.0061

0.0063

0.0062

0.0052

Thickness（m）

0.00184

0.003

0.0046

0.0049

0.0045

0.0031

Length（mm）

30

30

30

30

30

30

Table3.1

Wt%

0%

0.1%

0.5%

1%

2%

10%

Crosssectionalarea（㎡）

1.18*10-5

1.83*10-5

2.8*10-5

3.09*10-5

2.8*10-5

1.6*10-5

Load（N）

15

17

35

25

8

2

Stress（N/m2）

1271186

928961

1250000

809061

285714

125000

Strain（mm/mm）

0.2%

0.2%

0.2%

0.2%

0.2%

0.2%

Elasticmodulus（Gpa）

0.63

0.44

0.62

0.42

0.14

0.063

Table3.2

AccordingtoEc（u）=EmVm+EpVp,Ec（l）=EpEm/（EpVm+EmVp）,Em（CB）=0.63GpaandEp（EpoxyResin）=250Gpa.

Wt%

100%

80%

70%

60%

40%

30%

20%

0%

Ec（u）（Gpa）

250.000

200.126

175.189

150.252

100.378

75.441

50.504

0.630

Ec（l）（Gpa）

250.000

3.119

2.088

1.569

1.048

0.899

0.787

0.630

Table3.3

AccordingtoTable3.3,

Fig3.1.

3.2Resultsanalyze.

3.2.1Theinfluenceofdifferentpercentageofcarbonblackonthemechanicalproperties.

AccordingtoTable3.1,

Wt%

0%

0.1%

0.5%

1%

2%

10%

Stress（N/m2）

1271186

928961

1250000

809061

285714

125000

Fig3.2

Wt%

0%

0.1%

0.5%

1%

2%

10%

Elasticmodulus（Gpa）

0.63

0.44

0.62

0.42

0.14

0.063

Fig3.3

Accordingtotextbook,becauseoftheadditionofcarbonblack,itcanproduceNano-metereffectincertainscope,thenanoparticlechainofcarbonblackuniformdispersionintotheepoxyresin,toenhancetheinterfaceadhesionofcarbonblackandepoxyresin,helpthestresstransmissionandbeartheload.Inaddition,thecarbonblackparticlechainhascertainelasticity,whenexogenousprocess,itcanabsorbenergyandenhancethetoughness.Withtheincreaseofcarbonblack,thetensilestrength,elongation,impactstrengthandbendingstrengthofcompositematerialsincreasegradually.Buttoomuchcarbonblack,leadtotheincreaseofviscosityofthesystem,carbonblackishardlyhomodisperseandmaybeduetodefectsresultingfromtheincreaseofporespace,thereforemakesperformancedegradation.

Fig3.2andFig3.3showstheresultofthisproject.Forstressandelasticmodulus,withtheadditionofcarbonblack,itsharplydecreased,andthensharplyincreased,afterthis,sharplydecreasedagain,atlast,slightlydecreased.Obviously,itisnotinconformitywiththetheoreticalresults.Whathappened?

Themainproblemmightbewiththeaddition