1、Designation: F648 10aStandard Specification forUltra-High-Molecular-Weight Polyethylene Powder andFabricated Form for Surgical Implants1This standard is issued under the fixed designation F648; the number immediately following the designation indicates the year of originaladoption or, in the case of
2、 revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers ultra-high molecular weightpolyethylene powder (UHMWPE) and fabricate
3、d forms in-tended for use in surgical implants.1.2 The requirements of this specification apply to UHM-WPE in two forms. One is virgin polymer powder (Section 4).The second is any form fabricated from this powder fromwhich a finished product is subsequently produced (Section 5).This specification ad
4、dresses material characteristics and doesnot apply to the packaged and sterilized finished implant.1.3 The requirements of this specification do not apply toUHMWPE virgin powder or fabricated forms intentionallycrosslinked or blended with other additives, for example,antioxidents.1.4 The biological
5、response to polyethylene in soft tissueand bone has been well characterized by a history of clinicaluse (1, 2, 3)2and by laboratory studies (4, 5, 6).1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 The following precauti
6、onary caveat pertains only to thetest method portion, Section 7, of this specification: Thisstandard does not purport to address all of the safety concerns,if any, associated with its use. It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and de
7、termine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:3D256 Test Methods for Determining the Izod PendulumImpact Resistance of PlasticsD638 Test Method for Tensile Properties of PlasticsD648 Test Method for Deflection Temperature of PlasticsUnder
8、 Flexural Load in the Edgewise PositionD790 Test Methods for Flexural Properties of Unreinforcedand Reinforced Plastics and Electrical Insulating MaterialsD792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD1505 Test Method for Density of Plastics by th
9、e Density-Gradient TechniqueD1898 Practice for Sampling of Plastics4D4020 Specification for Ultra-High-Molecular-WeightPolyethylene Molding and Extrusion MaterialsF619 Practice for Extraction of Medical PlasticsF748 Practice for Selecting Generic Biological Test Meth-ods for Materials and DevicesF74
10、9 Practice for Evaluating Material Extracts by Intracu-taneous Injection in the RabbitF756 Practice for Assessment of Hemolytic Properties ofMaterialsF763 Practice for Short-Term Screening of Implant Materi-alsF813 Practice for Direct Contact Cell Culture Evaluation ofMaterials for Medical DevicesF8
11、95 Test Method for Agar Diffusion Cell Culture Screen-ing for CytotoxicityF981 Practice for Assessment of Compatibility of Biomate-rials for Surgical Implants with Respect to Effect ofMaterials on Muscle and Bone2.2 ISO StandardsISO 527 Plastics: Determination of Tensile Properties5ISO 3451-1 Plasti
12、csDetermination of Ash, Part 1: Gen-eral Methods5ISO 11542/2 PlasticsUltra-High Molecular Weight Poly-ethylene (UHMWPE) Moulding and ExtrusionMaterialsPart 2: Preparation of Test Specimens andDetermination53. Terminology3.1 Definitions of Terms Specific to This Standard:1This specification is under
13、the jurisdiction of ASTM Committee F04 onMedical and Surgical Materials and Devices and is the direct responsibility ofSubcommittee F04.11 on Polymeric Materials.Current edition approved Dec. 1, 2010. Published December 2010. Originallyapproved in 1980. Last previous edition approved in 2010 as F648
14、 10. DOI:10.1520/F0648-10a.2The boldface numbers in parentheses refer to the list of references at the end ofthis specification.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informatio
15、n, refer to the standards Document Summary page onthe ASTM website.4Withdrawn.5Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
16、2959, United States.3.1.1 fabricated form, nany bulk shape of UHMWPE,fabricated from the virgin polymer powder and used during theprocess of fabricating surgical implants prior to packaging andsterilization.3.1.1.1 DiscussionThis form results from the applicationof heat and pressure to the virgin po
17、lymer powder, and thematerial characteristics of this form are subject to the appli-cable requirements of this specification. In present practice,this includes ram-extruded bars or molded blocks from whichthe final product form is machined, or a molded shape which issubsequently trimmed.3.1.2 generi
18、c property, nthat property which is deter-mined solely by the chemical composition and structure of thevirgin polymer.3.1.3 morphology index (MI), nratio of the total numberof Type A and Type B indications (see Annex A2) to the totalsurface area examined in cm2.3.1.4 Type A non-fused flake, na Type
19、A non-fused flake(A2.4.1 and Fig.A2.1) is an indication visible under conditionsdescribed in A2.5.1 that has an essentially complete circum-ferential black boundary and a white center.3.1.5 Type B non-fused flake, na Type B non-fused flake(A2.4.2 and Fig.A2.2) is an indication visible under conditio
20、nsdescribed in A2.5.1 that has a partially circumferential blackboundary that appears to trace out 50 % to 99 % of a flakesperimeter.3.1.6 virgin polymer powder, nform of UHMWPE asobtained from the powder manufacturer and prior to fabricationinto a bulk shape.4. Virgin UHMWPE Powder Requirements4.1
21、Generic Properties:4.1.1 The virgin polymer shall be a homopolymer of ethyl-ene in accordance with Specification D4020.4.1.2 The resin type and solution viscosity number require-ments are listed in Table 1.4.2 Nongeneric Properties:4.2.1 When a 300 g sample is prepared and viewed inaccordance with 7
22、.1.2, there shall be no more particles ofextraneous matter than that specified in Table 1.4.2.2 To promote uniformity between different lots of poly-mer powder, concentration limits for trace elements have beenestablished and are listed in Table 1.4.2.3 When determined as described in ISO 3451-1, th
23、emean ash of duplicate samples shall not exceed the limitsestablished in Table 1.5. UHMWPE Fabricated Form Requirements5.1 Compositional Requirements:5.1.1 No stabilizers, antioxidants, or processing aids are tobe added to the virgin polymer powder during manufacture ofa fabricated form.5.1.2 No sta
24、bilizers, antioxidants, or processing aids are tobe added to the fabricated form during manufacture of the finalimplant.5.2 Physical Requirements:5.2.1 Foreign Matter Requirements:5.2.1.1 When 5000 cm2is evaluated according to 7.2.2,there shall be no more than ten particles of extraneous mattervisib
25、le on the surface when visually inspected by a person withnormal or fully corrected vision.5.2.2 Morphology Requirements:5.2.2.1 When evaluated according to Annex A2 the calcu-lated morphology index (MI) and total surface area examinedshall be reported.5.3 Mechanical Requirements:5.3.1 UHMWPE in fab
26、ricated form from which implantsshall be made shall meet the requirements listed in Table 2.5.3.2 The following mechanical tests may be conductedbased on agreement between the vendor and purchaser:5.3.2.1 Deflection temperature; Test Method D648 (1.8MPa), and Flexural modulus; Test Methods D790 (sec
27、ant, 2 %offset).6. Sampling6.1 Where applicable, the requirements of this specificationshall be determined for each lot of powder and fabricated formby sampling sizes and procedures according to Practice D1898,or as agreed upon between the purchaser and seller.7. Test Methods7.1 UHMWPE Powder:7.1.1
28、Determine the solution viscosity number in accor-dance with the method given in Specification D4020 at aconcentration of 0.02 %.7.1.2 Determine the amount of extraneous matter by thefollowing procedure as agreed upon by the purchaser andseller.7.1.2.1 A 300 g sample is divided into four 75 g samples
29、.Place a 75 g sample in each of four 1000 mL Erlenmeyerflasks, add 400 mL isopropyl alcohol, shake 5 min, and letsettle for 5 min. Count the total number of particles ofextraneous matter in the four flasks.7.1.2.2 Visually examine (20/20 corrected vision if neces-sary) the four flasks and count the
30、total number of particles ofextraneous matter.7.1.3 Determine the following trace element concentrationsby the following methods, or by methods agreed upon by thepurchaser and seller.TABLE 1 Requirements for UHMWPE PowdersProperty Test Method RequirementResin Type Type 1 Type 2 Type 3Viscosity Numbe
31、r, mL/g, ASTM D4020 (0.02 %) 2000-3200 3200 3200Elongation Stress,(Minimum)ASTM D4020 0.20 0.42 0.42Ash, mg/kg, (Maximum) ISO 3451-1 125 125 300Extraneous Matter, No.Particles, (Maximum)4.2.1 3325Titanium, mg/kg, (Maximum) 7.1.3.1 40 40 150Aluminum, mg/kg, (Maximum) 7.1.3.1 20 20 100Calcium, mg/kg,
32、(Maximum) 7.1.3.1 5550Chlorine, mg/kg, (Maximum) 7.1.3.2 30 30 90 Editorially corrected.F648 10a27.1.3.1 The elements Ti, Al, and Ca may be determined byatomic absorption (AA) or emission spectroscopy (ES); induc-tively coupled plasma mass spectroscopy (ICP/MS); or induc-tively coupled plasma spectr
33、oscopy (ICP).7.1.3.2 The element chlorine (Cl) may be determined po-tentiometrically, titrametrically, by neutron activation analysis,by inductively coupled plasma mass spectroscopy (ICP/MS),or by the oxygen bomb combustion/UV-Vis spectroscopymethod.7.2 UHMWPE Fabricated Form:7.2.1 The requirement t
34、hat there will be no addition of anystabilizer, antioxidant, or processing aid during fabrication ofthe fabricated form shall be met by certification of thefabricator.7.2.2 Determine the amount of extraneous matter by thefollowing procedure.7.2.2.1 Prepare a number of test specimens from the fabri-c
35、ated form as agreed upon by the purchaser and seller.7.2.2.2 Visually examine (20/20 corrected vision if neces-sary) a total area of 5000 cm2taken from locations within thefabricated form agreed upon by the purchaser and seller.7.2.3 Determine the density in accordance with Test Meth-ods D792 or D15
36、05.7.2.4 Determine specific mechanical properties in accor-dance with the methods listed in Table 2. Mechanical testspecimens shall be produced by methods that represent thoseused to produce the fabricated form.7.2.5 Unless otherwise specified, the testing described inTable 2 (except for ash) shall
37、be conducted under standardconditions of 23 6 2C after storage of the test specimens forat least 16 h.8. Biocompatibility8.1 This material has been shown to produce a well char-acterized level of biological response following long termclinical use in laboratory animals. The results of these studiesa
38、nd the clinical history indicate an acceptable level of biologi-cal response in the applications in which the material has beenutilized. When new applications of the material, or modifica-tion to the material or physical forms of the materials are beingcontemplated, the recommendations of Practice F
39、748 shouldbe considered and testing as described in Practices F619, F749,F756, F763, F813, and F981 as well as Test Method F895.9. Keywords9.1 fabricated forms; powdered form; ultra-high molecularweight polyethyleneANNEXES(Mandatory Information)A1. IMPACT STRENGTHA1.1 General DescriptionA1.1.1 This
40、test method covers the determination of theimpact resistance of Ultra-High Molecular Weight Polyethyl-ene (UHMWPE) which is extremely impact resistant. Whentested according to Test Method D256, Method A, UHMWPEgenerally gives a non-break type for failure, rendering the testresult invalid. This test
41、method specifies the same type ofpendulum impact test machine as given in Test Method D256but introduces a much higher degree of stress concentrationinto the specimen by double notching with a razor blade. It isadvised that the user be familiar with Test Method D256 beforeattempting to use this test
42、 method.TABLE 2 Requirements for UHMWPE Fabricated FormsProperty Test Method RequirementResin Type Type 1 Type 2 Type 3Density, kg/m3ASTM D792 or D1505 927-944 927-944 927-944Ash, mg/kg, (Maximum) ISO 3451-1 125 125 300Tensile Strength, 23C, MPa,(Minimum)AASTM D638, Type IV, 1.5 mm 6 0.5 mm,5.08 cm/
43、minUltimate 40 40 27Yield ISO 527, Type IV, 1.5 mm 6 0.5 mm,100 mm/min21 19 19Elongation, %, (Minimum)AASTM D638, Type IV, 5.08 cm/min 380 340 250ISO 527, 100 mm/min.Izod Impact Strength, kJ/m2,(Minimum)BAnnex A1 126 73 25Charpy Impact Strength, kJ/m2,(Minimum)BISO 11542/2 180 90 30AEither Test Meth
44、od D638 or ISO 527 may be used to determine tensile strength and elongation, however the ISO 527 method will be considered the referee method.An extensometer shall be used for measuring strain and calculating percent elongation.BEither Charpy or Izod impact strength may be determined, however, the C
45、harpy test will be considered the referee method.F648 10a3A1.2 ApparatusA1.2.1 The Izod type impact machine which conforms tothe requirements of Test Method D256, including the calibra-tion and checking methods, shall be used.A1.3 Test SpecimenA1.3.1 The geometry and dimensions of the specimen aregi
46、ven in Fig. A1.1.A1.3.2 The specimens shall be made from the fabricatedform.A1.3.3 Each specimen shall be free of twist and shall bebounded by mutually perpendicular pairs of plane parallelsurfaces, free from scratches, pits, and sink marks.A1.4 Notching of SpecimensA1.4.1 Notching shall be done on
47、the sides parallel to thedirection of application of molding pressure; if applicable.A1.4.2 A 4.57 6 0.076 mm (0.180 6 0.003 in.) deep notchshall be made with a suitable machine by pressing in a 0.25mm (0.010 in.) thick single edge razor blade with a 15included angle at the cutting edge. The notchin
48、g speed shall beless than 508 mm/min. (20 in./min.).Anew blade shall be usedafter notching 40 specimens.A1.4.3 The calibration of the notching machine shall bechecked by direct measurement of the notch depth, perpen-dicularity, and offset of the two notches. One of the possiblemeasurement methods is
49、 given in A1.8.A1.5 ConditioningA1.5.1 ConditioningCondition the notched specimens at23 6 2C (73 6 4F) for not less than 16 h prior to test.A1.5.2 Test ConditionsConduct the test in the standardlaboratory atmosphere of 23 6 2C (73 6 4F).A1.6 ProcedureA1.6.1 At least five and preferably ten individual determi-nations of impact value must be made on each sample to betested under the conditions prescribed.A1.6.2 Measure the width of each specimen in the areabetween notches twice with a micrometer to the nearest 0.025mm (0.001 in.) and record its average width.
