Designation:D1418−17StandardPracticeforRubberandRubberLatices—Nomenclature1ThisstandardisissuedunderthefixeddesignationD1418;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.INTRODUCTIONThesystemofdesignatingrubbersandrubberlaticesinthispracticewasdevelopedin1955toreplacedesignationsGR-A,GR-I,GR-M,GR-SandGR-T(standingfor“GovernmentRubber”:A-acrylontrile,I-isobutylene,S-styrene,M-monochlorobutadieneandT-thiosulfide),usedforsyn-theticrubbersmadeingovernmentownedplants.Thesystemwasdesignedtobeagenericclassificationoftherubberpolymersthatwouldaccommodatebothexistingandfuturerubbers.Thechemicalcompositionofthepolymerchainwasselectedasthebestclassificationproposaltoachievethisgoal.TherubberpolymersweredividedintoeightclassesasdescribedinSection3ofthispractice.Thelettersymbolfortheclasswasgivenlastinthedesignationfortherubber.Precedingtheclasssymbolwerelettersymbolstodesignateeitherthemonomersusedtopreparethepolymerorthesubstituentgroupsonthepolymerchain.Thesystemhasbeensuccessfulbothinaccommodatingthemanynewpolymersdevelopedsince1955andinconveyingtotheusercertaincharacteristicsoftherubberassociatedwiththechemicalcomposition.1.Scope1.1Thispracticecoversasystemofgeneralclassificationforthebasicrubbersbothindryandlatexformsdeterminedfromthechemicalcompositionofthepolymerchain.1.2Thepurposeofthispracticeistoprovideastandardiza-tionoftermsforuseinindustry,commerce,andgovernmentandisnotintendedtoconflictwithbutrathertoactasasupplementtoexistingtradenamesandtrademarks.1.3Intechnicalpapersorpresentationsthenameofthepolymershouldbeusedifpossible.Thesymbolscanfollowthechemicalnameforuseinlaterreferences.NOTE1—Fortermsrelatedtothermoplasticelastomers,seePracticeD5538.2.ReferencedDocuments2.1ASTMStand...
