1、Designation: F 2381 04Standard Test Method forEvaluating Trans-Vinylene Yield in Irradiated Ultra-High-Molecular-Weight Polyethylene Fabricated Forms Intendedfor Surgical Implants by Infrared Spectroscopy1This standard is issued under the fixed designation F 2381; the number immediately following th
2、e 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method descri
3、bes the measurement of thenumber of trans-vinylene groups in ultra-high molecularweight-weight polyethylene (UHMWPE) intended for use inmedical implants. The material is analyzed by infrared spec-troscopy.1.2 This test method is based on Guide F 2102.1.3 The applicability of the infrared method has
4、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 E 691.1.4 This standard does not purport
5、 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:2E 691
6、Practice for Conducting an Interlaboratory Study toDetermine Precision of a Test MethodE 1421 Practice for Describing and Measuring Performanceof Fourier Transform Infrared (FTIR) Spectrometers: LevelZero and Level One TestsF 2102 Guide for Evaluating the Extent of Oxidation inUltra-High-Molecular-W
7、eight Polyethylene FabricatedForms Intended for Surgical Implants3. Terminology3.1 Definitions:3.1.1 trans-vinylene index (TVI)a trans-vinylene index isdefined as the ratio of the absorption peak area between 950and 980 cm-1to the absorption peak area between 1330 and1396 cm-1.3.1.2 depth locator (D
8、L)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 inde
9、x 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 rad
10、iation 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 ad
11、jacent 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 deter
12、mine 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:5.1.1 A
13、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 a1This test method is under the jurisdiction of ASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct re
14、sponsibility of SubcommitteeF04.15 on Materials Test Methods.Current edition approved Apr. 1, 2004. Published April 2004.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refe
15、r to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.resolution of 4 cm-1and an aperture of approximately 200 by200 m for a rectangular aperture, or 200 m diameter for acircular
16、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 resu
17、lt ina loss of profile accuracy.5.1.1.2 When a Fourier Transform Infrared (FTIR) spec-trometer is used, a minimum of 32 scans shall be collected perspectrum.5.1.1.3 The FTIR instrument and sample compartmentshould be purged with a moisture- and carbon-dioxide-freeinert gas (for example, nitrogen, he
18、lium, or argon) to minimizespectral interference from these components.5.2 Specimen HolderEquipment, such as an x-y table,capable of accurately positioning the sample under the FTIRaperture with a minimum resolution at the scale of the aperturedimensions.5.3 MicrotomeEquipment capable of producing f
19、ilms ofthickness 200 m or less of a sample perpendicular to thearticular surface or the surface of interest.6. Sampling, Test Specimens, and Test Units6.1 Using a microtome, or other appropriate device, preparea thin slice of the sample about 200 m thick. If the detectedsignal from the FTIR is too w
20、eak with this thickness, a thickersample may be used.6.2 The slice shall typically be taken near the center of thesamples articular surface or the surface of interest.6.3 The orientation of the slice shall typically be perpen-dicular to the articular surface or the surface of interest.6.4 Waviness i
21、n the infrared spectrum caused by Fourierrippling on the lower wavelengths can interfere with thetrans-vinylene absorbance at 965 cm-1. This rippling is causedby internal reflection of the infrared beam, and can be avoidedby lightly rubbing the sample film against 400 grit sandpaperuntil the film be
22、comes translucent. This roughening procedureshould be done slowly to avoid heating the film, and should beperformed until the area under a single peak due to Fourierrippling is less than 10 % of the area under the trans-vinylenepeak.7. Preparation of Apparatus7.1 Prepare the infrared spectrometer fo
23、r collection of atransmission absorption spectrum from a thin film of theUHMWPE sample according to the manufacturers recommen-dations, Practice E 1421, and the conditions described in 5.1.8. Procedure8.1 The test film (slice) shall be first configured in thespectrometer (after an appropriate backgr
24、ound spectrum hasbeen collected) such that the aperture is positioned over thefirst 200 m of the film starting at the surface of interest.8.2 Subsequent spectra shall be collected sequentially atincrements matching the aperture size (that is, about 200 m)from the articular surface, or surface of int
25、erest, across thewidth of the film to the opposite surface.8.3 Larger increments may be used; however, too large anincrement size may result in a loss of profile accuracy.9. Calculation of Results9.1 Trans-vinylene Peak Area:9.1.1 For each absorbance spectrum, calculate the total areaof the peak abs
26、orptions between 950 and 980 cm-1(see Fig. 1).NOTEFourier rippling disappears with increased surface roughening. The original absorption peaks are unaffected by the surface roughening.FIG. 1 FTIR Spectra of Thin UHMWPE Film Showing the Effects of Roughening on Fourier RipplingF23810429.1.2 This area
27、 is the area below the samples absorbancecurve and above the straight baseline drawn between the samestarting and ending points, namely 950 and 980 cm-1.9.2 Normalization of Peak Area:9.2.1 For each absorbance spectrum, calculate the total areaof the peak absorptions between 1330 and 1396 cm-1(see F
28、ig.2).9.2.2 This area is the area below the samples absorbancecurve and above the straight baseline drawn between the samestarting and ending points, namely 1330 and 1396 cm-1.9.3 Trans-vinylene Index (TVI)For each absorbance spec-trum, calculate its TVI by dividing the area of its trans-vinylenepea
29、k (see 9.1) by the area of its normalization peak (see 9.2).9.4 Depth Locator (DL)Calculate the distance from thearticular surface, or surface of interest, termed the depth locator(DL), for each spectrum and its corresponding TVI from thefollowing equation:DL 5 0.5A! 1 nS! (1)where:A = the size of t
30、he aperture in micrometers in the stepdirection,n = the number of steps (increments) the aperture had beenmoved from its initial location at the articular surfaceor surface of interest, andS = the step (increment) size in micrometers.10. Report10.1 The report shall contain at least the following exp
31、eri-mental details and results:10.1.1 Material Information:10.1.1.1 Resin type and resin lot number,10.1.1.2 Consolidation method and manufacturer and manu-facturer lot number, and10.1.1.3 Any special post-consolidation treatments, for ex-ample, HIPing, annealing, sterilization, crosslinking, stabil
32、iza-tion, accelerated aging, and storage conditions.10.1.2 Sample Information:10.1.2.1 Indicate whether the sample is an orthopedic im-plant or laboratory test specimen,10.1.2.2 Articular surface or non-articular surface,10.1.2.3 Test samples original dimensions,10.1.2.4 Any special post-treatments
33、of the original testsample, for example, annealing, sterilization, crosslinking,stabilization, accelerated aging, and storage conditions,10.1.2.5 Test film thickness and total width, and10.1.2.6 Any special post-treatments of the test films, forexample, annealing, sterilization, crosslinking, stabil
34、ization,accelerated aging, and storage conditions.10.1.3 Spectrometer Information:10.1.3.1 Manufacturer and model number,10.1.3.2 Analog or Fourier transform spectrometer, and10.1.3.3 Aperture dimensions, profile step size, spectralresolution, and number of scans per spectrum.FIG. 2 Typical FTIR Spe
35、ctrum of Radiation-Crosslinked UHMWPE, Showing the Definition of an Area-Based Trans-VinyleneIndex Based on the Normalization Peak at 1370 cm-1F238104310.1.4 Data Analysis Information:10.1.4.1 Manual or by spectrometers software algorithms.11. Precision and Bias11.1 Precision and bias data will be f
36、orthcoming followinga round-robin test.12. Keywords12.1 crosslinking; FTIR (Fourier Transform Infrared); im-plant; trans-vinylene index; TVI; UHMWPE(ultra-high-molecular-weight-polyethylene)APPENDIX(Nonmandatory Information)X1. RATIONALEX1.1 The extent of crosslinking present in orthopedicimplant co
37、mponents made of UHMWPE has been shown toaffect both mechanical properties and wear behavior. It istherefore important to have standard methods for assessing thedegree of crosslinking of such materials.X1.2 The method described herein is an adaptation ofmethods described in the literature, and of ot
38、her ASTMstandards.X1.3 The intensity (area) of the trans-vinylene absorptions(-C=C-) centered near 965 cm-1is related to the amount ofcrosslinking experienced by the material when exposed toionizing radiation. The correlation between TVI and actualreceived radiation dose depends on the nature of the
39、 irradiationconditions, for example, radiation source (gamma or electronbeam), temperature, dose rate, and oxygen level. To determineradiation doses from TVI measurements, a calibration curvemust be prepared for the specific radiation conditions used,using validated dosimeters (such as photochromic
40、dyes) as anindicator of the delivered radiation dose.X1.4 This test method is useful for assessing the uniformityof crosslinking in an irradiated component or pre-form.X1.5 This test method does not specify desired levels ofTVI to achieve optimal functional characteristics.REFERENCES(1) Muratoglu, O
41、. K., OConnor, D. O., Bragdon, C. R., Delaney, J., Jasty,M., Harris, W. H., Merrill, E., and Venugopalan, P., “GradientCrosslinking of UHMWPE Using Irradiation in Molten State for TotalJoint Arthroplasty,” Biomaterials, 23, 2002, pp. 717-724.(2) Muratoglu, O. K., Harris, W. H., “Identification and Q
42、uantification ofIrradiation in UHMWPE Through Trans-vinylene Yield,” J. Biomed.Mat. Res., 56, 2001, PP. 584-592.(3) Lyons, B. J., Johnson, W. C., “Radiolytic Formation and Decay ofTrans-vinylene Unsaturation in Polyethylene,” Irradiation of Poly-meric Materials: Processes, Mechanisms, and Applicatio
43、ns, Reichma-nis et al., ed., American Chemical Society, Washington, D.C., Vol 527,1993, pp. 62-73.(4) Johnson, W. C., Lyons, B. J., “Radiolytic Formation and Decay ofTrans-vinylene Unsaturation in Polyethylene: Fournier TransformInfra-Red Measurements,” Rad. Phys. Chem., 46, 1995, pp. 829-832.(5) Ly
44、ons, B. J., “Role of Intramolecular Crosslinking in the Radiolysis ofBulk Crystallized High Density Polyethylene,” Rad. Phys. Chem., 28,1986, pp. 149-155.(6) McLaughlin, W. L., Silverman, J., Al-Sheikhly, M., Chappas, W. J.,Zhan-Jun, L., Miller, A., and Batsberg-Pedersen, W., “High DensityPolyethyle
45、ne Dosimetry by Trans-vinylene FTIR Analysis,” Rad.Phys. Chem., 56, 1999, pp. 503-508.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of t
46、he validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Yo
47、ur comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comment
48、s have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F2381044
