WATERABSORPTIONFLAMMABILITYANDMECHANICALPROPERTIES

ISSN-L:2223-9553,ISSN:2223-9944Vol.4No.1January2013AcademicResearchInternational©2013SAVAPInternational–Onyegbula2DepartmentofPolymerandTextileEngineering,FederalUniversityofTechnologyOwerri,ImoState,[e-mail],[e-mail]sampleswereproducedusinginjectionmoldingbymixingLLDPEwithvarying(5,10,15,20,25)wt%ofeggshellpowdertoobtaindesiredandenhancedproperties.Waterabsorption,flammabilityandmechanicalpropertiesoflinearlowdensitypolyethylene/eggshellpowdercompositesasafunctionoffillercontentintheparticlesizes(75,125,175μm)wereinvestigated.Theparameterssuchastensilestrength,elongationatbreak,tensilemodulus,andimpactandflexuraltestwerecarriedoutonthepreparedcompositesamples.Experimentalresultshowedsignificantdecreaseintensilestrength,%elongationatbreak,tensilemodulus,flexuralstrengthandflexuralmodulusonadditionofeggshellpowderintothematrix.Flammabilitybehaviourofthecompositesasafunctionoffillercontentexaminedshowedgradualreductionasthefillercontentincreaseswhilewaterabsorptionbehaviourofthecompositesasfunctionoftimeofexposureinvestigatedincreasedasthetimeofexposureandfillercontentincreases.Keywords:LLDPE,polymercomposite,eggshell,waterabsorption,flammability.INTRODUCTIONThermoplasticsarepolymersthatsoftenwithoutchemicalchangeandhardenwhencooled,andmayberemouldedmanytimesbutsubjecttochemicaldegradation(Katchy,2000).Theyareincreasingreplacingconventionalmaterialssuchasmetal,glass,woodandpaperindiverseapplications(Obasi,2007).Thebroadspectrumofpropertiesofferedbythevarietyofthermoplasticstogetherwiththetechniquesofcompoundingthemwithotherpolymers,chemicaladditivesandfillershasbeenaneffectiveandvitaltoolforachievingspecificbalancedcombinationofphysicalpropertiesandprocessingcharacteristics(Obasi,2007).Theselectionofthermoplasticcompositeforaspecificcompositeapplicationisdeterminedbytheprocessinghistory,mechanicalproperties,thermalstability,chemicalpropertiesandcost.Manyfactorssuchasthefillerproperties,fillercontent,interfacialadhesionanddistributioninfluencethepropertiesofthermoplasticcompositesduetocombinationofmorethanonematerialinthecomposite(Hussein,etal.,2011).Linearlowdensitypolyethylene(LLDPE)isacommoditythermoplastic(Fried,2003)andwidelyusedindifferentapplicationswhichinclude;filmpackaging(bagsandSheet),cablecovering,toys,lids,buckets,containers,pipes(HansDominighaus,1993).Thepredominantapplicationsoflinearlowdensitypolyethyleneisduetoitstoughness,flexibility,relativetransparency,lowmoistureabsorption,chemicalandcorrosionresistance,gooddielectriccharacteristicsandbarrierproperties,environmentalstresscrackingresistanceandexcellentheatsealstrength.InordertoenhancethephysicalpropertiesandreducecostofprocessingLLDPEcomposite,someadditivescanbeincorporatedintothecomposite.ParticulatefillersPart-II:NaturalandAppliedSciencesISSN-L:2223-9553,ISSN:2223-9944Vol.4No.1January2013Copyright©2013SAVAPInternational(2011),Nwanonenyi&Obidiegwu(2012),Mahanar&Bose(2004),Anyanwu&Ogbobe(2007),andNjokuaetal.(2011)havebeenreportedinscientificliteratureforimprovingthemechanicalpropertiesofthermoplasticcompositesatreducedcost.Thisstudyfocusedoftheeffectoffillercontentandparticlesizeontheflammability,waterabsorptionandmechanicalpropertiesofeggshellpowderfilledlinearlowdensitypolyethylene.EXPERIMENTALMaterialsTheLLDPEusedinthestudywaspurchasedfromaChemicalStoreatAba,AbiaState,Nigeria.Ithasameltflowindexof2.5g/minanddensity0.929g/cm3.Eggshellpowderwasobtainedfromalocalmarket.PreparationofCompositeSamplesTheeggshellwassubjectedtocleaningwithwatertoremovecontaminants,driedatroomtemperatureforsixhoursinanoventoeliminateodourandgroundtopowderwiththeofblender.Differentsetofsievewereusedtoobtainaverageparticlesizeof(75,125,175μm).Afterthateggshellpowderwasaddedtothematrixindifferent(5,10,15,20,25)wt%asshowninTable1.Then,eggshellasafinepowderwasmixed,meltblendedwithLLDPEat1900Cinasinglescrewinjectionmouldingmachineandasquareframesamplewasfabricatedin2-5mins(processingtime),andafterthisperiodthesamplewasallowedtocool.Table1.FormulationofLLDPEandEggshellSampleIDLLDPE(%)Eggshell(%)1100021005310010410015510020CHARACTERIZATIONANDMEASUREMENTSTensileTestTensilestrength(ASTMD638)wasevaluatedusinguniversaltensiletestingmachineofLR10K.FlexuralpropertiesaccordingtoASTMD790weretestedusingLR10Kmachine.WaterAbsorptionTest(ASTMD570)Waterabsorptiontest(ASTMD570)wasdonebytotalimmersionofthreespecimensindistilledwateratroomtemperature.Thewaterabsorbedwasdeterminedbyweighingthesamplesatregularintervals(i.e,weightgain)withtheaidofdigitalweighingbalance.Thewateradheringonthesurfaceofthespecimenwascarefullyremovedusingfilterpaper;carewastakenduringthewipingprocessnottoremovethewaterabsorbedbythespecimen.TheISSN-L:2223-9553,ISSN