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Designation:D1238–04StandardTestMethodforMeltFlowRatesofThermoplasticsbyExtrusionPlastometer1ThisstandardisissuedunderthefixeddesignationD1238;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thistestmethodcoversmeasurementoftherateofextrusionofmoltenresinsthroughadieofaspecifiedlengthanddiameterunderprescribedconditionsoftemperature,load,andpistonpositioninthebarrelasthetimedmeasurementisbeingmade.1.2ProcedureAisamanualcutoffoperationbasedontimeusedformaterialshavingflowratesthatfallgenerallybetween0.15and50g/10min.ProcedureBisanautomaticallytimedflowratemeasurementusedformaterialshavingflowsfrom0.50to900g/10min.Bybothprocedures,thepistontravelisgenerallythesameduringthetimedmeasurement;thepistonfootisabout46and20.6mmabovethedie.Comparableflowrateshavebeenobtainedbytheseproceduresininterlaboratoryround-robinmeasurementsofseveralmaterialsdescribedin13.1.Provisionismadeforcalculationofmeltvolume-flowrateaswellasmeltmass-flowrate.NOTE1—Round-robintestingindicatesthistestmethodmaybesuit-ableatflowratesupto1500g/10minifthetimingclockresolvestheelapsedtimetothenearest0.01s.NOTE2—ThistestmethodandISO1133-1991aretechnicallyequiva-lent.1.3Thisstandarddoesnotpurporttoaddressthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.Specificprecautionarystatementsaregivenin5.7,10.2.12,and14.1.2.2.ReferencedDocuments2.1ASTMStandards:2D618PracticeforConditioningPlasticsforTestingD883TerminologyRelatingtoPlasticsE691PracticeforConductinganInterlaboratoryStudytoDeterminethePrecisionofaTestMethod2.2ANSIStandard:B46.1onSurfaceTexture32.3ISOStandard:ISO1133-1991DeterminationoftheMelt-MassFlowRate(MFR)andtheMeltVolume-FlowRate(MVR)ofTher-moplastics33.Terminology3.1General:3.1.1FordefinitionofsomeofthetechnicaltermsusedinthistestmethodrefertoTerminologyD883.4.SignificanceandUse4.1Thistestmethodisparticularlyusefulforqualitycontroltestsonthermoplastics.NOTE3—Polymershavingflowrateslessthan0.15orgreaterthan900g/10minmaybetestedbytheproceduresinthistestmethod;however,precisiondatahavenotbeendeveloped.4.2Thistestmethodservestoindicatetheuniformityoftheflowrateofthepolymerasmadebyanindividualprocessand,inthiscase,maybeindicativeofuniformityofotherproper-ties.However,uniformityofflowrateamongvariouspolymersasmadebyvariousprocessesdoesnot,intheabsenceofothertests,indicateuniformityofotherproperties.4.3Theflowrateobtainedwiththeextrusionplastometerisnotafundamentalpolymerproperty.Itisanempiricallydefinedparametercriticallyinfluencedbythephysicalproper-tiesandmolecularstructureofthepolymerandtheconditionsofmeasurement.Therheologicalcharacteristicsofpolymermeltsdependonanumberofvariables.Sincethevaluesofthesevariablesoccurringinthistestmaydiffersubstantiallyfromthoseinlarge-scaleprocesses,testresultsmaynotcorrelatedirectlywithprocessingbehavior.4.4Theflowrateofamaterialmaybemeasuredunderanyoftheconditionslistedforitin8.2.Additionalcharacterizationofamaterialcanbeobtainedifmorethanoneconditionisused.Incasetwoconditionsareemployed,aFlowRateRatio(FRR)maybeobtainedbydividingtheflowrateatoneconditionbytheflowrateattheothercondition.1ThistestmethodisunderthejurisdictionofASTMCommitteeD20onPlasticsandisthedirectresponsibilityofSubcommitteeD20.30onThermalProperties(SectionD20.30.08).CurrenteditionapprovedMarch1,2004.PublishedApril2004.Originallyapprovedin1965.Lastpreviouseditionapprovedin2001asD1238-01e1.2ForreferencedASTMstandards,visittheASTMwebsite,@astm.org.ForAnnualBookofASTMStandardsvolumeinformation,refertothestandard’sDocumentSummarypageontheASTMwebsite.3AvailablefromAmericanNationalStandardsInstitute(ANSI),25W.43rdSt.,4thFloor,NewYork,NY10036.1*ASummaryofChangessectionappearsattheendofthisstandard.Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.5.Apparatus5.1Plastometer:5.1.1Theapparatusshallbeadead-weightpistonplastom-eterconsistingofathermostaticallycontrolledheatedsteelcylinderwithadieatthelowerendandaweightedpistonoperatingwithinthecylinder.Theessentialfeaturesoftheplastometer,illustratedinFigs.1and2,aredescribedin5.2-5.8.Alldimensionalmeasurementsshallbemadewhenthearticlebeingmeasuredisat2365°C.5.1.2Relativelyminorchangesinthedesignandarrange-mentofthecomponentpartshavebeenshowntocausedifferencesinresultsamonglaboratories.Itisimportant,therefore,forthebestinterlaboratoryagreementthatthedesignadherecloselytothedescriptionherein;otherwise,itshouldbedeterminedthatmodificationsdonotinfluencetheresults.5.2Cylinder—Thesteelcylindershallbe50.8mmindiameter,162mminlengthwithasmooth,straighthole9.550460.0076mmindiameter,displaced4.8mmfromthecylinderaxis.Wellsforathermalsensor(thermoregulator,thermistor,etc.)andth