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Designation:D2857–95(Reapproved2001)StandardPracticeforDiluteSolutionViscosityofPolymers1ThisstandardisissuedunderthefixeddesignationD2857;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoversthedeterminationofthedilutesolutionviscosityofpolymers.ThereareseveralASTMstandards(TestMethodsD789,D1243,D1601,andD4603,andPracticeD3591)thatdescribedilutesolutionviscosityproceduresforspecificpolymers,suchasnylon,poly(vinylchloride),polyethylene,andpoly(ethyleneterephthalate).Thispracticeiswrittentoaugmentthesestandardswhenproblemsarisewithwhichthespecificprocedureisnotconcerned,orwhennostandardisavailableforthepolymerunderinvesti-gation.1.2Thispracticeisapplicabletoallpolymersthatdissolvecompletelywithoutchemicalreactionordegradationtoformsolutionsthatarestablewithtimeatatemperaturebetweenambientand150°C.Resultsareusuallyexpressedasrelativeviscosity(viscosityratio),inherentviscosity(logarithmicvis-cositynumber),orintrinsicviscosity(limitingviscositynum-ber)(see3.1).1.3Forpolyamides,relativeviscosityvaluesbythisproce-durearenotequivalenttothosedeterminedbyTestMethodsD789.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.NOTE1—ThisstandardandISO1628,“Plastics—DeterminationofViscosityNumberandLimitingViscosityNumber,”aretechnicallyequivalent.2.ReferencedDocuments2.1ASTMStandards:D445TestMethodforKinematicViscosityofTransparentandOpaqueLiquids2D446SpecificationsandOperatingInstructionsforGlassCapillaryKinematicViscometers2D789TestMethodsforDeterminationofRelativeViscos-ity,andMoistureContentofPolyamide(PA)3D883TerminologyRelatingtoPlastics3D1243TestMethodforDiluteSolutionViscosityofVinylChloridePolymers3D1600TerminologyforAbbreviatedTermsRelatingtoPlastics3D1601TestMethodforDiluteSolutionViscosityofEth-ylenePolymers3D3591PracticeforDeterminingLogarithmicViscosityNumberofPoly(VinylChloride)(PVC)inFormulatedCompounds4D4603TestMethodforDeterminingInherentViscosityofPoly(EthyleneTerephthalate)(PET)byGlassCapillaryViscometer5D5226PracticeforDissolvingPolymerMaterials5E1SpecificationforASTMThermometers62.2ISOStandard:1628/1GuidelinesfortheStandardizationofMethodsfortheDeterminationofViscosityNumberandLimitingViscosityNumberofPolymersinDiluteSolution72.3NationalInstituteofStandardsandTechnologyDocu-ment:CircularNo.C602TestingofGlassVolumetricApparatus83.Terminology3.1Definitions—TermsanddefinitionsinTerminologyD883andabbreviationsinTerminologyD1600areapplicabletothispractice.Thefollowingdefinitions9areapplicabletothispractice.3.1.1inherentviscosity,hinh,n—theratioofthenaturallogarithmoftherelativeviscositytothemassconcentrationofthepolymer,c:hinh=(lnhr)/c.3.1.1.1Discussion—Alsoknownasthelogarithmicviscos-itynumber,hln.Seealso3.1.3.1ThispracticeisunderthejurisdictionofASTMCommitteeD20onPlasticsandisthedirectresponsibilityofSubcommitteeD20.70onAnalyticalMethods.CurrenteditionapprovedFebruary15,1995.PublishedApril1995.OriginallypublishedasD2857–70.LastpreviouseditionD2857–93.2AnnualBookofASTMStandards,Vol05.01.3AnnualBookofASTMStandards,Vol08.01.4AnnualBookofASTMStandards,Vol08.02.5AnnualBookofASTMStandards,Vol08.03.6AnnualBookofASTMStandards,Vol14.03.7AvailablefromAmericanNationalStandardsInstitute,11W.42ndSt.,13thFloor,NewYork,NY10036.8AvailablefromNationalInstituteofStandardsandTechnology,U.S.Depart-mentofCommerce,Washington,DC20234.9InternationalUnionofPureandAppliedChemistry,CompendiumofMacro-molecularNomenclature,BlackwellScientificPublications,Oxford,England,1991.1Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.3.1.2intrinsicviscosity,[h],n—thelimitingvalueofthereducedviscosityortheinherentviscosityatinfinitedilutionofthepolymer:@h#5c→0lim~hi/c!5c→0limhinh.3.1.2.1Discussion—AlsoknownasthelimitingviscositynumberandintheliteratureastheStaudingerindex.Seealso3.1.3.3.1.3reducedviscosity,n—theratiooftherelativeviscosityincrementtothemassconcentrationofthepolymer,c,thatis,hi/c.3.1.3.1Discussion—Alsoknownastheviscositynumber.Theunitmustbespecified;cm3/gisrecommended.3.1.3.2Discussion—Thisquantityandthosedefinedin3.1.1and3.1.2areneitherviscositiesnorpurenumbers.Thetermsaretobelookeduponastraditionalnames.Anyreplacementbyconsistentterminologywouldproduceunnec-essaryconfusioninthepolymerliterature.3.1.4relativeviscosity,hr,n—theratiooftheviscosityofthesolution,h,totheviscosityofthesolvent,hs,thatis,hr=h/hs.3.1.4.1Discussion—Alsoknownastheviscosityratio.3.1.5relativeviscosityincrement,hi,n—theratioofthedifferencebetweentheviscositiesofsolutionandsolventtotheviscosityofthesolvent,thatis,hi=(h−hs)/hs.3.1.5.1Discussion—Theuseofthetermspecificviscosityforthisquantityisdiscouraged,sinc