nylon 6

INTERNATIONALJOURNALOFAPPLIEDENGINEERINGRESEARCH,DINDIGULVolume2,No 2,2011

Copyright2010AllrightsreservedIntegratedPublishingAssociation

REVIEWARTICLE ISSN 09764259

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EnhancementofImpactresistancepropertyofNylon6bytheadditionofCasio3asafillermaterial

MithunVKulkarni1,Elangovan.K2,HemachandraReddy.K3,PrakashJN4

1Researchscholar,JNTUCollegeofEngineering,Anantapur515002,AP,India2AssistantProfessor,CambridgeInstituteofTechnology,Bangalore560036,Karnataka,

India3Professor,DepartmentofMechanicalEngineering,JNTUCollegeofEngineering,

Anantapur515002,AndhraPradesh,India4Professor,DepartmentofMechanicalEngineering,EastWestInstituteoftechnology,

Bangalore560091,Karnataka,[email protected]

ABSTRACT

Impactresistanceisoneofthemostimportantpropertiesforcomponentdesignerstoconsider,aswellasthemostdifficulttoquantify.Impactresistanceisacriticalmeasureofservicelifeandmore importantly these days, it involves the perplexing problemof product safety andliability.TheaimofthispaperistounderstandtheinfluenceofCasio3 (CalciumSilicate)onthe impactpropertiesofPolyamides(Nylon6)and itscomposites.TheNylon6 isreinforcedwith varying percentages (1%, 3% and 5%) of Casio3. The dropweight impact testswereconducted on the samples at different drop heights of 320 mm, 620 mm, 1000 mm anddifferent drop weights of 0.89 kg, 1.395 kg and 2.33 kg. Impact measurement under theabovesaidconditionsforthematerialsA,B,CandDindicatedthattheadditionof Casio3ledtoasignificantimprovementintheimpactstrengthofthepolyamides.

Keywords: Droptest,Polyamides,Nylon6,Impact,Calciumsilicate,Fillers

1.Introduction

Theimpactenergyofamaterialistheamountofenergyrequiredtofractureagivenvolumeofthematerial(Bows,J.R.1999).Therefore,theimpactstrengthofamaterial istheenergyrequiredtoinitiateandpropagateacrackthroughthematerial.Thecrackpropagationenergyisrelatedtothetoughnessofthematerialandthelengthofthatcracktipthatmusttravel inordertofractureacomponent.Thismeansthelowerthevalueoftheimpactenergythemorebrittle the material behaves (Askeland, D.R. 1998). Impact tests are frequently used instudyingdynamicbehaviorofmaterialsaswellasstructures,e.g.crashworthinessofvehicles,dynamic constitutive behavior of structural materials and impact performance of vehiclecomponents. Impact performance can be one of the most important properties for acomponentdesigner toconsiderandalsothemostdifficult toquantify,Impacttestsallowdesigners to compare the relative impact resistance under controlled laboratory conditionsand,consequently,areoftenusedformaterialselectionorqualitycontrol.Traditionalimpacttests evaluate the energy required to cause failure, however they do not provide goodinformationaboutmechanismornatureof failure, suchasbrittleorductile failure,becausethesetestsaregenerallynotinstrumentedtomeasurestressandstraininthespecimenduringthe test, moreover, finished components can have very different impact performancecharacteristics than raw material specimens. Lowvelocity impact has been an important




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study inmaterialcharacterization (HandbookofPolymerTestingShortTermMechanicalTests),duetoitscommonoccurrenceintherealworld.Asanefficientwaytoperformlowvelocity impact tests, dropweight impact testing machines have been commonly used.However,becauseofthelimitofthedropheight,theimpactvelocityproducedbythedropweightimpacttestingmachinesisusuallylessthan10m/s(GuojingLiandDahsinLiu.,2008).Inrecentyears,avarietyoffillershavebeeninvestigatedforreinforcementofthermoplasticpolymers (Ulrich A.Handge , KatrinHedickeHchsttter , VolkerAltstdt. ., 2010).Theimpact properties of polyamide blends have been influenced by the addition of fibers andcalciumsilicate,asignificantinfluenceinthechangeofmechanicalpropertieshasalsobeenobserved(Gnatowski,JandKoszkul.,2005).Polyamideshavebeenphysicallymodifiedbyfilling themwithpowdermineralfillers like talc,graphite,molybdenumdisulphide,bariumsulphate (VI) and titanium white. In the present work, a vertical drop weight impact testmachine has been used to study the influence of Casio3 (Calcium Silicate) on the impactpropertiesofPolyamides(Nylon6)anditscomposites.TheNylon6isreinforcedwithvaryingpercentages(1%,3%and5%)ofCasio3 (CalciumSilicate).Thetestswereconductedonthesamplesatdifferentdropheightsof320mm,620mm,1000mmanddifferentdropweightsof0.89kg,1.395kgand2.33kg.

2.Experimental

2.1MaterialsandSamplePreparation

Thematerials/samplesandthesamplepreparationmethodshavebeendescribedinTable1.The materials under study were classified into four types viz., Material A, Material B,MaterialCandMaterialD.Atotalof36specimenswereusedfortesting.

Table1:Thematerials/samplesandthesamplepreparationmethods

SampleCode MaterialsunderStudy MethodofSamplePreparationMaterialA Nylon6 InjectionMoldingMaterialB Nylon6+1%Casio3 InjectionMoldingMaterialC Nylon6+3%Casio3 InjectionMoldingMaterialD Nylon6+5%Casio3 InjectionMolding

Nylon 6 pellets procured from M/s Sarvodaya polymers, Bangalore, India were used topreparetheMaterialAspecimensandNylon6alongwith1%,3%and5%Casio3wereusedto prepareMaterial B, C, andD specimens. The Specimenswere prepared by heating thepellets in the barrel of an injection molding machine. The temperature was set at 1000 Cinitiallyfor30minutesandassoonastheflowofthematerialstartedfromthenozzleoftheinjectionmoldingmachine,thetemperatureofthebarrelwasreducedto600C.Inthemeantimethemoldwasalsocleanedandpreheated.Theliquefiedmaterialwastheninjectedintothemold and thus the samples were prepared . The prepared specimens were of 50mm x50mmx4mmdimensions.

2.2ImpactTest

Impact test was conducted as per ASTM D5628 on four different types of specimens assummarizedinTable1,usingaverticaldropweighttestingmachine.Parameterslikemassof




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hammer, impactenergy (dropheightofhammer)werevaried,but theshapeof hammer tipwaskeptconstant.TheDropheightusedinthetestwere320mm,620mmand1000mmanddropweightsusedwereof0.89kg, 1.395kgand2.33kg.

3.ResultsandDiscussions

All the samples were tested for different drop weights and drop heights. The data wasrecordedforeachsamplethesamplesunderstudywereclassifiedintoA,B,CandD(Table1).ThedartortheImpactorwasdroppedfromtheheightof320mm,620mm,1000mmandthedropweightsusedwereof0.89kg,1.395kg,and2.33kg.ForDifferentDropweightsandheightstheEnergyduetofallingdrop,E1,wascalculatedaccordingtothekineticenergyrelation(KE=0.5mv2).AsafirststepinthisresearchworktheimpacttestwasconductedonNylon6andthetestresultswererecordedinTable2.Next,theNylon6wasreinforcedwith1%,3%and5%ofCasio3asafillermaterial.ThedropweightimpacttestwasconductedonthesespecimensanditwasobservedthattheE3(Energyabsorbedbythematerial)valueofmaterialB,CandDhadincreasedincomparisonwithmaterialA(Figures4,5,6).Theusageof Casio3 as a filler material to improve the toughness of Nylon6 had served thepurpose.%E3 for the materials A, B, C, D were found to be 59.39%, 64.37%, 68.42%,72.44%fromthetables2,3,4,5respectively.i.e.,anincreaseof8.38%,15.24%and21.97%wereobservedinmaterialB,CandDrespectivelyincomparisonwithmaterialA.Similarly,Energy due to impact load, E2, of materials A, B, C, D were 105.46, 107.42, 118.7 and145.18Joulesrespectively.NosubstantialincreaseinE2wasfoundinmaterialBincontrasttomaterialA,butanincreaseof37.6%E2wasfoundinmaterialDincontrasttomaterialA.Increase in E2 and E3 indicated that the impact property of Nylon6 improved with theadditionofCasio3.

Table2:ImpactTestresultforMaterialA(Nylon6)

DropHeight,mm Mass,Kg ImpactSpeed,m/s E1,J

ImpactLoad,Kg E2,J E3,J %E3

320 0.89 2.51 2.8 1.55 4.87 2.07 42.45320 1.395 2.51 4.4 2.25 7.06 2.66 37.70320 2.33 2.51 7.3 4.5 14.13 6.83 48.32620 0.89 3.49 5.4 2.3 13.99 8.59 61.40620 1.395 3.49 8.5 3.4 20.68 12.18 58.90620 2.33 3.49 14.2 5.4 32.84 18.64 56.761000 0.89 4.43 8.7 3.2 31.39 22.69 72.291000 1.395 4.43 13.7 6.45 63.27 49.57 78.351000 2.33 4.43 22.8 10.75 105.46 82.66 78.38

Table3:ImpactTestDataforMaterialB(Nylon6+1%Casio3)



320 0.89 2.51 2.8 1.99 6.25 3.45 55.18320 1.395 2.51 4.4 2.95 9.26 4.86 52.49320 2.33 2.51 7.3 4.9 15.38 8.08 52.54620 0.89 3.49 5.4 2.05 12.47 7.07 56.69620 1.395 3.49 8.5 3.35 20.37 11.87 58.28620 2.33 3.49 14.2 6.25 38.01 23.81 62.64




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1000 0.89 4.43 8.7 4.5 44.14 35.44 80.291000 1.395 4.43 13.7 7.95 77.99 64.29 82.431000 2.33 4.43 22.8 10.95 107.42 84.62 78.77

Table4:ImpactTestDataforMaterialC(Nylon6+3%Casio3)



320 0.89 2.51 2.8 2.1 6.59 3.79 57.53320 1.395 2.51 4.4 3.05 9.57 5.17 54.04320 2.33 2.51 7.3 5.25 16.48 9.18 55.70620 0.89 3.49 5.4 2.4 14.60 9.20 63.01620 1.395 3.49 8.5 6.95 42.27 33.77 79.89620 2.33 3.49 14.2 8.6 52.31 38.11 72.851000 0.89 4.43 8.7 2.8 27.47 18.77 68.331000 1.395 4.43 13.7 8.55 83.87 70.17 83.671000 2.33 4.43 22.8 12.1 118.70 95.90 80.79

Table5:ImpactTestDataformaterialD(Nylon6+5%Casio3)



320 0.89 2.51 2.8 2.35 7.38 4.58 62.04320 1.395 2.51 4.4 3.4 10.67 6.27 58.77320 2.33 2.51 7.3 9.3 29.19 21.89 74.99620 0.89 3.49 5.4 3.5 21.29 15.89 74.63620 1.395 3.49 8.5 4.35 26.46 17.96 67.87620 2.33 3.49 14.2 13.05 79.37 65.17 82.111000 0.89 4.43 8.7 3.9 38.26 29.56 77.261000 1.395 4.43 13.7 4.65 45.62 31.92 69.97

1000 2.33 4.4322.8

14.8 145.18122.38 84.30




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Figure4:ImpactLoadonMaterialsA,B,C,andDfor320mmdropheightandvaryingdropweights





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4.Conclusions

LowvelocityImpacttestwasconductedsuccessfullyonfourdifferentmaterialsviz.,Nylon6,Nylon6+1%Casio3,Nylon6+3%Casio3andNylon6+5%Casio3.Acomparisonofimpactvalueswasmade in between thesematerials. The tests showed that under the dropweightimpact, the Casio3 reinforced materials exhibited a good improved Impact resistance. ThehighaspectratioofCasio3wasakeyfactorinimprovingthemechanicalperformanceofthecompositesofNylon6andCasio3,thishighaspectratioreducesthemobilityofthepolymerchainstherebyincreasingtheimpactresistance.Also,withtheincreaseinCasio3percentage,the adhesion of the matrix onto the mineral particles increases thus reducing the air gapswhichrepresentthepointof zerostrength.

5.References

1. A. Gnatowski, J. Koszkul (2005), investigations of the influence of filler on thepropertiesofchosenpolymerblendswithcompatibilizeraddition,13th InternationalScientific Conference on Achievements in Mechanical and Materials Engineering.,Gliwice,Poland.

2. Askeland,D.R (1998), theScienceandEngineeringofMaterials,3rdedn,pp.163164,StanleyThornes,USA.




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3. Bows, J.R (1999), variable Frequency Microwave Heating of Food, Journal ofMicrowavePowerandElectromagneticEnergy,34(4),pp227238.

4. GuojingLiandDahsinLiu(2008),anInstrumentedFreeProjectileforLowvelocityImpactTesting,Proceedingsof theXIthInternationalCongressandExpositionJune25,Orlando,FloridaUSA

5. Roger Brown (2002), handbook of Polymer Testing ShortTermMechanical Tests,RapraTechnologyLimited,

6. UlrichA.Handge,KatrinHedickeHchsttter ,VolkerAltstdt (2010), compositesof polyamide 6 and silicate nanotubes of the mineral halloysite: Influence ofmolecularweightonthermal,mechanicalandrheologicalproperties.Polymer,51,pp26902699

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