Designation:D7252−17StandardTestMethodforPolyurethaneRawMaterials:DeterminationofMonomerandIsomersinIsocyanates1ThisstandardisissuedunderthefixeddesignationD7252;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethoddeterminesthepercentbyweightofmonomericisomersandtotalmonomerincrudeormodifiedisocyanates.Thetestmethodisapplicabletomethylenedi(phe-nylisocyanate)(MDI)andpolymeric(methylenephenylisocya-nate)(PMDI).(SeeNote1.)1.2Units—ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.NOTE1—ThereisnoknownISOequivalenttothisstandard.1.4Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:2D883TerminologyRelatingtoPlasticsE682PracticeforLiquidChromatographyTermsandRela-tionshipsE691PracticeforConductinganInterlaboratoryStudytoDeterminethePrecisionofaTestMethod3.Terminology3.1FordefinitionsoftermsusedinthesetestmethodsseeTerminologyD883.4.SummaryofTestMethod4.1Thesampleisreacted(derivatized)withmethanoltoformamixtureofmethylurethanes.Theurethanesmixtureisthenseparatedbynormalphasehighperformanceliquidchromatography(HPLC).Theseparated,derivatizedisomersarequantifiedthroughtheuseofaninternalstandard.5.SignificanceandUse5.1Thistestmethodisusedforresearchorforqualitycontroltocharacterizeisocyanatesus...
