Designation:D2857−22StandardPracticeforDiluteSolutionViscosityofPolymers1ThisstandardisissuedunderthefixeddesignationD2857;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thispracticecoversthedeterminationofthedilutesolutionviscosityofpolymers.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-durearenotequivalenttothosedeterminedbyTestMethodsD789.1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.NOTE1—ThisstandardandISO1628,“Plastics—DeterminationofViscosityNumberandLimitingViscosityNumber,”aretechnicallyequivalent.1.6Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendations...
