ASTM_F_2381_-_10.pdf

Designation:F238110Standard Test Method forEvaluating Trans-Vinylene Yield in Irradiated Ultra-HighMolecular Weight Polyethylene Fabricated Forms Intendedfor Surgical Implants by Infrared Spectroscopy1This standard is issued under the fixed designation F2381;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes the measurement of thenumber of trans-vinylene groups in ultra-high molecularweight polyethylene(UHMWPE)intended for use in medicalimplants.The material is analyzed by infrared spectroscopy.1.2 This test method is based on Guide F2102.1.3 The applicability of the infrared method has beendemonstrated in other literature reports.This particularmethod,using the intensity(area)of the C-H absorptioncentered at 1370 cm-1to normalize for the samples thickness,will be validated by an Interlaboratory Study(ILS)conductedaccording to Practice E691.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1421 Practice for Describing and Measuring Performanceof Fourier Transform Mid-Infrared(FT-MIR)Spectrom-eters:Level Zero and Level One TestsF2102 Guide for Evaluating the Extent of Oxidation inPolyethylene Fabricated Forms Intended for SurgicalImplants3.Terminology3.1 Definitions:3.1.1 trans-vinylene index(TVI)a trans-vinylene index isdefined as the ratio of the area of the absorption peak centerednear 965 cm-1to the area of the absorption peak centered near1370 cm-1.3.1.2 depth locator(DL)a measurement of the distancefrom the articular surface,or surface of interest,that a spectrumwas collected and a corresponding TVI calculated.3.1.3 trans-vinylene index profilea trans-vinylene indexprofile is defined as the graphical representation of variation ofthe samples trans-vinylene index with distance from itsarticular surface or the surface of interest.This is a plot of TVIversus DL.Typically,the graph will show the profile throughthe entire thickness of the sample.4.Significance and Use4.1 Published literature shows that the yield of radiolyticreactions that occur during radiation treatment increases withradiation dose level.Measurement of the products of thesereactions can be used as an internal dosimeter.4.2 Trans-vinylene unsaturations are formed during ioniza-tion treatment by abstraction of a hydrogen molecule,and to alesser extent by the recombination of two adjacent alkyl freeradicals that reside on the same chain.4.3 Previous work generated calibration curves of trans-vinylene absorption area as a function of absorbed radiationdose,yielding a linear relationship for both gamma-andelectron beam-irradiated polyethylene.4.4 This data can be used to determine received dose as afunction of position,assuming a calibration curve(TVI versusradiation dose level)is known for the particular material andradiation conditions used,and can be used to determineuniformity of dose level in irradiated polyethylene.5.Apparatus5.1 Infrared Spectrometer:1This test method is under the jurisdiction ofASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.15 on Material Test Methods.Current edition approved June 1,2010.Published July 2010.Originally approved2004.Last previous edition approved in 2004 as F238104.DOI:10.1520/F2381-10.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.1.1 A calibrated infrared spectrometer capable of record-ing a transmission absorption spectrum over a minimum rangeof 900 to about 2000 cm-1using about 200 m-thick films at aresolution of 4 cm-1and an aperture of approximately 200 by200 m for a rectangular aperture,or 200 m diameter for acircular aperture.5.1.1.1 Other modes of collection(that is,reflection,attenu-ated total reflection(ATR),and so forth)and aperture andsampling step sizes may be used to generate the samplesabsorption spectrum provided they can be demonstrated toproduce equivalent results.Too large an aperture can result ina loss of profile accuracy.5.1.1.2 When a Fourier Transform Infrared