Designation:F2183−02(Reapproved2008)StandardTestMethodforSmallPunchTestingofUltra-HighMolecularWeightPolyethyleneUsedinSurgicalImplants1ThisstandardisissuedunderthefixeddesignationF2183;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofmechanicalbehaviorofultra-highmolecularweightpolyethylene(UHM-WPE)bysmallpunchtestingofminiaturediskspecimens(0.5mminthicknessand6.4mmindiameter).ThetestmethodhasbeenestablishedforcharacterizingUHMWPEsurgicalmate-rialsafterramextrusionorcompressionmolding(1,2)2;forevaluatingas-manufacturedimplantsafterradiationcrosslink-ingandsterilization(3,4);aswellasfortestingofimplantsthathavebeenretrieved(explanted)fromthehumanbody(5,6).1.2Theparametersofthesmallpunchtest,namelythepeakload,ultimatedisplacement,ultimateload,andworktofailure,providemetricsoftheyielding,ultimatestrength,ductility,andtoughnessofUHMWPEundermultiaxialloadingconditions.BecausethemechanicalbehaviorofUHMWPEisdifferentwhenloadedunderuniaxialandmultiaxialloadingconditions(3),thesmallpunchtestprovidesacomplementarymechanicaltestingtechniquetotheuniaxialtensiletestingspecifiedformedicalgradeUHMWPEbySpecificationF648.1.3Inadditiontoitsuseasaresearchtoolinimplantretrievalanalysis,thesmallpunchtestcanbeusedasalaboratoryscreeningtesttoevaluatenewUHMWPEmaterials,suchasthosecreatedbygammaorelectronbeamirradiation(1).ThetestmethodisalsowellsuitedforcharacterizationofUHMWPEbeforeandafteracceleratedaging(forexample,GuideF2003),andinthatregarditcanproviderankingofthemechanicaldegradationofdifferentUHMWPEsamplesafteroxidativedegradation(4,7).1.4Thesmallpunchtesthasbeenappliedtootherpolymers,includingpolymethylmethacrylate(PMMA)bonecement,polyacetal,andhighdensitypolyethylene(HDPE)(8,9).However,thesmallpunchtestingofpolymersotherthan...
