AMERICANNATIONALANSI/ASTMD2342-68(Reapproved1972)STANDARDStandardTestMethodforLOT-TO-LOTSTABILIZATIONUNIFORMITYOFPROPYLENEPLASTICS1ThisStandard_isissuedunderthe_fixeddesignationD2342;thenumberimmediatelyfollowingthedesignationindicatestheyearofongtnaladoptionor,tnthecaseofrev1s1on,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.I.ScopeI.IThismethodcoverstwoproceduresfordeterminingthestabilityofpropyleneplasticswhenexposedtoairinthemoltenstateforarelativelybriefperiodoftime:I.1.1ProcedureA-withoutthepresenceofcopper.1.1.2ProcedureB-withthepresenceofcopper.NOTEI-ThevaluesstatedinSIunitsaretoberegardedasthestandard.2.SummaryofMethod2.1Plasticpelletsareexposedinaluminumorcopperdishesinacirculating-airovenat185Cfordefinitetimeperiods.Thermaloxi-dativestabilityundertheseconditionsisde-terminedvisuallybycomparingthecooleddiskofheatedplasticwithastandardorbymeasuringanychangeinitsflowratebyASTMMethodD1238,MeasuringFlowRatesofThermoplasticsbyExtrusionPlas-tometer.'3.Significance3.1Theseproceduresareintendedprimar-ilyasameansforrapidqualitycontrol.Theyservetoindicatetheuniformityofthethermaloxidativestabilityofamaterialasproducedfromlot-to-lotinaparticularcompositionbyasinglemanufacturer.3.2Thetestcandetectdifferencesamongmaterialshavingdifferentlevelsandtypesofstabilizers.ProcedureAisapplicabletoallpropyleneplastics.TheuseofProcedureBisgenerallylimitedtomaterialsthatarespecifi-callydesignedforapplicationsinwhichthereisdirectcontactoftheplasticwithcopperoritsalloys.3.3Duetothecomplexitiesofpolymeroxidativedegradationanditsretardationandtheirdependenceonsuchfactorsastempera-tureandtime,thedataobtainedbythesepro-ceduresformaterialsofvariouspolymerandstabilizationtypesmaynotcorrelatewithbehaviorunderactualuseconditions.There-fore,theseproceduresarenotrecommendedforratingorqualifyingsuchmaterialsintheabsenceofotherlong-termaginginformation.4.Apparatus4.1Oven-Air-circulatingovencapableofmaintainingauniformtemperatureandanairflowof75to140m/min(approxim...
