Designation:D2765−16StandardTestMethodsforDeterminationofGelContentandSwellRatioofCrosslinkedEthylenePlastics1ThisstandardisissuedunderthefixeddesignationD2765;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thegelcontent(insolublefraction)producedinethyl-eneplasticsbycrosslinkingisdeterminedbyextractingwithsolventssuchasdecahydronaphthaleneorxylenes.Themeth-odsdescribedhereinareapplicabletocrosslinkedethyleneplasticsofalldensities,includingthosecontainingfillers,andallprovidecorrectionsfortheinertfillerspresentinsomeofthosecompounds.1.2TestMethodA,whichpermitsmostcompleteextractioninleasttime,istobeusedforrefereetests,buttwoalternativenonrefereeTestMethodsBandCarealsodescribed.TestMethodBdiffersfromtherefereetestmethodonlyinsamplepreparation;thatis,itrequiresuseofshavingstakenatselectedpointsincableinsulation,forexample,ratherthanthegroundsamplerequiredbytherefereetestmethod.Becausetheshavedparticlesarelarger,lesstotalsurfacepersampleisexposedtotheextractant,sothistestmethodordinarilyyieldsextractionvaluesabout1to2%lowerthantherefereemethod.TestMethodCrequiresthataspecimeninonepiecebeextractedinxylenesataconstanttemperatureof110°C.Atthistemperatureandwithaone-piecespecimen,evenlessextractionoccurs(from3to9%lessthantherefereetestmethod),thismethodpermitsswellratio(ameasureofthedegreeofcrosslinkinginthegelphase)bedetermined.1.3Extractiontestsaremadeonarticlesofanyshape.Theyhavebeenparticularlyusefulforelectricalinsulationssincespecimenscanbeselectedfromthoseportionsoftheinsulationmostsusceptibletoinsufficientcrosslinking.1.4ThevaluesstatedineitherSIunitsorinch-poundunitsaretoberegardedseparatelyasstandard.Thevaluesstatedineachsystemmaynotbeexactequivalents;therefore,eachsystemshallbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayr...
