Designation:D4883−18StandardTestMethodforDensityofPolyethylenebytheUltrasoundTechnique1ThisstandardisissuedunderthefixeddesignationD4883;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thistestmethodcoversthedeterminationofthedensityofpolyethylenethroughtheutilizationofultrasoundequip-ment.1.2Thistestmethodisbasedonthedistinctbehaviorsoftheamorphousandcrystallinephasesofpolyethyleneinresponsetoultrasound.Polyethyleneshallbeviewedasacompositestructurewherehigh-densitycrystallineregionsareconnectedbylower-densityamorphousmaterial.Theratioofcrystallinetoamorphousmaterialdeterminesthefinaldensityofthematerial.Theamorphousandcrystallinephasesexhibitverydistinctbehaviorswithregardtothepropagationofsoundwaves.Thepropagationcharacteristicsinthecompositewilldependontherelativeamountofthetwophases(thedegreeofcrystallinity).1.3InorganicmaterialsincreasedensityasmeasuredbyTestMethodsD792andD1505,buttheyhavelittleornoeffectonultrasonicdensity.Theultrasonicmeasurementisbasicallyabaseresindensity.1.4ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.NOTE1—ThereisnoknownISOequivalenttothisstandard.1.6Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:2D618PracticeforConditioningPlasticsforTestin...
