1、Designation: F 1839 08Standard Specification forRigid Polyurethane Foam for Use as a Standard Material forTesting Orthopaedic Devices and Instruments1This standard is issued under the fixed designation F 1839; the number immediately following the designation indicates the year oforiginal adoption or
2、, 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 specification covers rigid unicellular polyurethanefoam for use as a stand
3、ard material for performing mechanicaltests utilizing orthopaedic devices or instruments. The specifi-cation is applicable to sheets or blocks of foam, or foam that ismade by the user using a two-part liquid mixture.1.2 This specification covers polyurethane foam materialthat is used in the laborato
4、ry for mechanical testing, asdescribed in 1.1. These materials are not intended for implan-tation into the human body.1.3 The foam described herein possesses mechanical prop-erties which are on the order of those reported for humancancellous bone. See Appendix X1 Rationale for furtherinformation reg
5、arding the appropriateness of using the speci-fied foam as a model for human cancellous bone.1.4 This specification covers compositional requirements,physical requirements, mechanical requirements, and testmethods for rigid polyurethane foam in the solid final form.1.5 This specification provides qu
6、alification criteria forvendor or end-user processes and acceptance criteria forindividual material lots.1.6 This specification provides mechanical properties of fivedifferent grades of foam in the solid final form. A foam thatdoes not meet the specified mechanical properties shall beidentified as a
7、n ungraded foam.1.7 Unless otherwise indicated, the values stated in SI unitsare to be regarded as standard. The values in parentheses aremathematical conversions to inch-pound units that are pro-vided for information only and are not considered standard.1.8 The following precautionary statement per
8、tains to thetest method portion only, Section 8, 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 determine the appl
9、icability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:2C 273 Test Method for Shear Properties of Sandwich CoreMaterialsD 1621 Test Method for Compressive Properties Of RigidCellular PlasticsD 1622 Test Method for Apparent Density of Rigid CellularPlasticsE4 Prac
10、tices for Force Verification of Testing MachinesF 543 Specification and Test Methods for Metallic MedicalBone Screws3. Terminology3.1 Definitions:3.1.1 final formthe condition of the foam product whenused by the end user to perform tests of orthopaedic devices orinstruments.3.1.1.1 DiscussionThis is
11、 the condition of the foam prod-uct of which all physical and mechanical tests required by thisspecification are performed.3.1.1.2 solidthe foam is in a uniform solid form, such asa slab, plate, or block.3.1.2 foam rise directionthe nominal direction that thefoam rises during the polymerization (“fo
12、aming”) process,either at the suppliers production facilities for the solidsupplied foam, or at the end-users facilities for foam producedfrom the liquid supplied form. The foam rise direction shall bemarked on the foam block or indicated in the shippingdocumentation for foam that is supplied in the
13、 solid form.3.1.3 gradesThe grade designation refers to the nominaldensity of the foam, in its solid final form, expressed in unitsof kg/m3(lbm/ft3). Ten grades of foam have been defined inthis specification. Their nominal densities are:Grade 5: 80.1 kg/m3(5.0 lbm/ft3)Grade 10: 160.2 kg/m3(10.0 lbm/
14、ft3)Grade 12: 192.2 kg/m3(12.0 lbm/ft3)Grade 15: 240.3 kg/m3(15.0 lbm/ft3)Grade 20: 320.4 kg/m3(20.0 lbm/ft3)1This specification is under the jurisdiction of ASTM Committee F04 onMedical and Surgical Materials and Devices and is the direct responsibility ofSubcommittee F04.21 on Osteosynthesis.Curre
15、nt edition approved Nov. 15, 2008. Published December 2008. Originallyapproved in 1997. Last previous edition approved in 2007 as F 1839 01(2007).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
16、 volume information, refer 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.Grade 25: 400.5 kg/m3(25.0 lbm/ft3)Grade 30: 480.5 kg/m3(30.0 lbm/ft3)Grade 35: 560.6 kg/m3(35.0 lbm
17、/ft3)Grade 40: 640.7 kg/m3(40.0 lbm/ft3)Grade 50: 800.9 kg/m3(50.0 lbm/ft3)Foam that does not fit into one of these ten grades becauseit does not meet one or more of the physical requirements ofSection 4 is termed ungraded.3.1.4 supplied formthe condition of the foam productwhen received from the su
18、pplier by the end user.3.1.4.1 DiscussionThe supplied form may be a solid or aliquid. The foam may be in a uniform solid form such as a slab,plate, or block or a liquid in which two liquid components(base and activator) can be mixed by the end user to producea rigid, unicellular foam slab.4. Physica
19、l and Mechanical Requirements4.1 CompositionThe material shall be supplied either insolid or liquid form. The solid or combined liquid parts shallproduce a foam consisting of polyether polyurethane.4.2 Appearance:4.2.1 Solid Supplied FormThe solid foam slab shall befree of obvious extraneous matter,
20、 and appear to the unaidedeye to be uniform throughout the slab in color and porosity.4.2.2 Liquid Supplied FormThe two liquid componentsshall appear to the unaided eye throughout their volumes to beuniform and free from obvious extraneous matter or particulatedebris.4.2.3 Solid Final FormThe solid
21、foam slab shall be freeof obvious extraneous matter, and appear to the unaided eye tobe uniform throughout the slab in color and porosity.4.3 Void ContentThe material in the solid final form shallmeet the requirements of Table 1 for voids, cracks andnonuniform areas, when examined using the procedur
22、es de-scribed in 8.1. All specimens shall meet this requirement.4.4 DensityThe material in the solid final form shall havea density within the ranges specified in Table 2, according tothe foams grade specification. The density shall be determinedusing the method described in 8.2. All specimens shall
23、 meetthis requirement.4.5 Dimensional StabilityThe material in the solid finalform shall have an average percentage thickness change lessthan 5.0 %, when tested according to the method described in8.3.4.6 Compressive StrengthThe material in the solid finalform shall meet the compressive strength req
24、uirements given inTable 3, when tested according to the method described in 8.4.All specimens shall meet this requirement.4.7 Compressive ModulusThe material in the solid finalform shall meet the compressive modulus requirements givenin Table 4, when tested according to the method described in8.4. A
25、ll specimens shall meet this requirement.4.8 Shear StrengthThe material in the solid final formshall meet the shear strength requirements given in Table 5,when tested according to the method described in 8.5. Allspecimens shall meet this requirement.4.9 Shear ModulusThe material in the solid final f
26、ormshall meet the shear modulus requirements given in Table 6,when tested according to the method described in 8.5. Allspecimens shall meet this requirement.4.10 Screw PulloutThe material in the solid final formshall meet the screw pullout requirements given in Table 7,when tested according to the m
27、ethod described in 8.6. Allspecimens shall meet this requirement.TABLE 1 Requirements for Voids, Cracks, and Nonuniform AreasDefects RequirementsVoidsVoid depth (measured perpendicularto slabs transverse plane)Void depth shall be less than 50 % ofthe slab thickness, and less than6.35 mm (0.250 in.)V
28、oid diameter (measured parallel toslabs transverse plane)Larger than 6.35 mm (0.250 in.) None allowed in any gradeBetween 3.18 mm (0.125 in.)and 6.35 mm (0.250 in.)No more than 10 allowed per 230cm2(36 in.2) surface area for Grades5 and 10. No more than 1 allowedfor Grades 12, 15, 20, 25, 30, and35.
29、 None allowed for Grades 40 and50.Between 1.57 mm (0.062 in.)and 3.18 mm (0.125 in.)No more than 20 allowed per 230cm2(36 in.2) surface area for Grades5 and 10. No more than 6 allowedfor Grades 12, 15, 20, 25, 30, and35. No more than 3 allowed forGrades 40 and 50.Cracks None allowedNon-uniform areas
30、 Concentrated areas of poorconstruction, irregular cells, and hardand soft spots shall not exceed 10 %of the visible surface areaTABLE 2 Grade Designation and DensityGradeMinimum Density,kg/m3(lbm/ft3)Maximum Density,kg/m3(lbm/ft3)5 72.10 (4.5) 88.10 (5.5)10 144.0 (9.0) 176.0 (11.0)12 173.0 (11.0) 2
31、11.5 (13.0)15 216.0 (13.5) 264.5 (16.5)20 288.5 (18.0) 352.5 (22.0)25 360.5 (22.5) 440.5 (27.5)30 432.5 (27.0) 528.5 (33.0)35 504.5 (31.5) 617.0 (38.5)40 576.5 (36.0) 705.0 (44.0)50 721.0 (45.0) 881.0 (55.0)TABLE 3 Requirements for Compressive StrengthGradeMinimum CompressiveStrength, MPa (psi)Maxim
32、um CompressiveStrength, MPa (psi)5 0.4495 (65.20) 0.7800 (113.0)10 1.745 (253.0) 2.820 (409.0)12 2.485 (360.5) 3.970 (576.0)15 3.820 (554.0) 6.050 (877.5)20 6.630 (961.5) 10.45 (1515)25 10.15 (1470) 16.00 (2320)30 14.30 (2075) 22.70 (3290)35 19.15 (2775) 30.55 (4430)40 24.60 (3570) 39.55 (5735)50 37
33、.35 (5415) 61.05 (8855)F18390825. Significance and Use5.1 This specification describes the compositional require-ments, physical requirements, mechanical requirements, andtest methods for rigid unicellular polyurethane foam for use intesting orthopaedic devices or instruments.5.2 This foam described
34、 in this specification is not intendedto replicate the mechanical properties of human or animalbone. The requirements of this specification are intended toprovide a consistent and uniform material with properties onthe order of human cancellous bone to use as a test mediumwhen testing various orthop
35、aedic devices, such as bone screws.6. Apparatus6.1 Analytical Balance or Scalecapable of weighing foamspecimens to the nearest mg.6.2 Micrometer Dial Gage or Calipercapable of measur-ing dimensions of the foam specimens to 60.1 %.6.3 Conditioning OvenForced-air circulating oven ca-pable of maintaini
36、ng 121 6 2.8C (250 6 5F) for 24 h.6.4 Desiccatorcontaining desiccant with high affinity forwater vapor (anhydrous calcium chloride or equivalent).6.5 Vacuum Apparatuscapable of applying a vacuumpressure of 508 mm (20 in.) of mercury to foam specimen fordimensional stability test.6.6 Testing Machine
37、and Load Cellconforming to Prac-tices E4and capable of applying tensile and compressive loadsat a constant displacement rate.7. Sampling and Test Specimens7.1 The number of test specimens and the specimen sizesrequired for physical characterization and mechanical testingare described in 8.1-8.6. Tes
38、t specimens are required for eachgrade and formulation.7.2 Test specimens shall be solid foam blocks. The short-transverse direction of the specimens shall coincide with thefoam rise direction of the original foam bun.8. Procedure8.1 Determination of Void Content:8.1.1 Use the foam block specimens d
39、escribed and specifiedin 8.2-8.6.8.1.2 Examine all of the surfaces and edges of test speci-mens for voids and nonuniform areas with the unaided eye.Measure the dimensions of the void or nonuniform areas usingan instrument capable of measuring 60.025 mm (0.001 in.).8.2 Determination of Foam Density:8
40、.2.1 Prepare three specimens, 25.4 by 25.4 by 25.4 mm (1by 1 by 1 in.) from solid foam.8.2.2 Determine the apparent density of the three foamspecimens, in kg/m3(lbm/ft3), in accordance with Test MethodD 1622.8.2.3 Calculate the average apparent density of the threefoam specimens.8.3 Determination of
41、 Dimensional Stability:8.3.1 Prepare three specimens, 25.4 by 25.4 by 12.7 mm (1by 1 by 0.5 in.) from solid foam.8.3.2 Condition the specimen for 24 h at 21 6 2.8C (70 65F) and 50 6 10 % relative humidity. Measure the specimenthickness near the center of the length to 60.025 mm (0.001in.) and mark t
42、he location of the measurement.8.3.3 Place the specimen on a 6.35-mm (0.25-in.) thickaluminum plate and apply a minimum vacuum pressure of 508mm (20 in.) of mercury under a vacuum bag or diaphragm.Place this assembly in a circulating forced-air oven for not lessthan2hat1216 2.8C (250 6 5F). Remove t
43、he assemblyand allow to cool to 49C (120F) or less while maintaining thevacuum.TABLE 4 Requirements for Compressive ModulusGradeMinimum CompressiveModulus, MPa (psi)Maximum CompressiveModulus, MPa (psi)5 12.30 (1780) 20.35 (2950)10 45.75 (6640) 71.70 (10 400)12 64.50 (9350) 100.5 (14 575)15 98.00 (1
44、4 200) 151.0 (21 900)20 167.5 (24 295) 257.5 (37 345)25 253.5 (36 770) 390.0 (56 565)30 355.5 (51 560) 548.5 (79 555)35 472.0 (68 460) 732.0 (106 170)40 603.0 (87 460) 941.0 (136 480)50 907.5 (131 620) 1435 (208 130)TABLE 5 Requirements for Shear StrengthGradeMinimum Shear Strength,MPa (psi)Maximum
45、Shear Strength,MPa (psi)5 0.420 (60.90) 0.805 (117.0)10 1.225 (177.5) 2.010 (291.5)12 1.610 (233.5) 2.580 (374.0)15 2.235 (324.0) 3.510 (509.0)20 3.395 (492.5) 5.275 (765.0)25 4.665 (676.5) 7.275 (1055)30 6.025 (874.0) 9.495 (1375)35 7.460 (1080) 11.95 (1735)40 8.960 (1300) 14.55 (2110)50 12.10 (175
46、5) 20.40 (2960)TABLE 6 Requirements for Shear ModulusGradeMinimum Shear Modulus,kPa (psi)Maximum Shear Modulus,kPa (psi)5 5.460 (792.0) 9.000 (1305)10 15.15 (2195) 22.75 (3300)12 19.70 (2855) 29.20 (4235)15 27.10 (3930) 39.70 (5760)20 40.75 (5910) 59.25 (8595)25 55.70 (8080) 81.15 (11 770)30 71.70 (
47、10 400) 105.0 (15 230)35 88.65 (12 860) 131.0 (19 000)40 106.5 (15 445) 159.0 (23 060)50 144.0 (20 885) 220.0 (31 910)TABLE 7 Requirements for Screw PulloutGradeMinimum Pullout,N (lb)Maximum Pullout,N (lb)5 56.00 (12.60) 176.0 (39.55)10 220.0 (49.45) 453.0 (102.0)12 309.5 (69.60) 592.5 (133.0)15 464
48、.5 (104.5) 831.0 (187.0)20 770.0 (173.0) 1310 (294.5)25 1125 (253.0) 1890 (425.0)30 1520 (341.5) 2570 (578.0)35 1950 (438.5) 3355 (754.0)40 2400 (539.5) 4245 (954.0)50 3380 (760.0) 6350 (1430)F18390838.3.4 Recondition and remeasure the thickness at themarked location in accordance with 8.3.2. Calcul
49、ate the per-cent thickness change.8.3.5 Calculate the average percent thickness change of thethree specimens.8.4 Determination of Compressive Strength and Modulus:8.4.1 Prepare five specimens, 50.8 by 50.8 by 25.4 mm (2by 2 by 1 in.), from solid foam, with the thickness of thespecimen parallel to the foam rise direction. Measure thedimensions within 60.025 mm (60.001 in.). The specimensshall be conditioned at 24 6 2.8C (75 6 5 F) for 3 h prior totesting.8.4.2 Test in accordance with Test Method D 1621 at 24 62.8C (75 6 5F). The specimens sha
