Designation:D4274−21StandardTestMethodsforTestingPolyurethaneRawMaterials:DeterminationofHydroxylNumbersofPolyols1ThisstandardisissuedunderthefixeddesignationD4274;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thesetestmethodsmeasurethehydroxylgroupsinpolyesterandpolyetherpolyolscontainingprimaryandsec-ondaryhydroxylgroups.Theyalsoapplytomanyotherhydroxyl-containingsubstances.1.1.1TestMethodA—AceticAnhydridePressureBottle,recommendedforpolyesters.1.1.2TestMethodB—PhthalicAnhydridePressureBottle,recommendedforpolyethersandpolyesters.1.1.3TestMethodC—PhthalicAnhydrideReflux,recom-mendedforpolyethersandpolyesters.1.1.4TestMethodD—Imidazole–CatalyzedPhthalicAnhy-dridePressureBottle,recommendedforpolyethers,polyesters,polymerpolyols,andamine-initiatedpolyols.1.1.5TestMethodE—Imidazole-CatalyzedPyromelliticDi-anhydrideEsterification,recommendedforpolyolsusedforflexibleandrigidpolyurethanefoamsandurethaneelastomers.Itisrecommendedforpolyesterpolyols,polyetherpolyols,amine-startedpolyols,andpolymerpolyols(polyacrylonitrile/copolystyrene-based).1.2AnotherASTMtestmethodformeasuringhydroxylgroupsisTestMethodE222.1.3ThevaluesstatedinSIunitsaretoberegardedasthestandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.NOTE1—Thisstandard,ISO14900andISO6796addressthesamesubjectmatter,butdifferintechnicalcontent.1.5Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganiza...
