1、Designation: F 1839 01 (Reapproved 2007)Standard Specification forRigid Polyurethane Foam for Use as a Standard Material forTesting Orthopedic Devices and Instruments1This standard is issued under the fixed designation F 1839; the number immediately following the designation indicates the year ofori
2、ginal 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 specification covers rigid unicellular polyurethanefoam
3、for use as a standard material for performing mechanicaltests utilizing orthopedic 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 use
4、d in the laboratory 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 furth
5、erinformation regarding 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 specific
6、ation provides qualification 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
7、beidentified as an ungraded foam.1.7 Unless otherwise indicated, the values stated in SI unitsare to be regarded as standard. The values in parentheses aregiven for information only.1.8 The following precautionary statement pertains to thetest method portion only, Section 8, of this specification: T
8、hisstandard 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 applicability of regulatory limita-tions prior to use.2. Referenced Documents
9、2.1 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 Practices for Force Verification of Testing MachinesF 543 Specification and T
10、est 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 orthopedic devices orinstruments. The condition of the foam product of which allphysical and mechanical tests required by this speci
11、fication areperformed.3.1.1.1 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 (“foaming”) process,either at the suppliers production facilities for the solidsupplied foam, or at the e
12、nd-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 solid form.3.1.3 gradesThe grade designation refers to the nominaldensity of the foam, in its solid
13、final form, expressed in unitsof kg/m3(lbm/ft3). Five grades of foam have been defined inthis specification. Their nominal densities are given below:Grade 10: 160.2 kg/m3(10.0 lbm/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)Grade 40: 6
14、40.7 kg/m3(40.0 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.Current edition approved Oct. 1, 2007. Published October 2007. Originallyapproved in 1997.
15、 Last previous edition approved in 2001 as F 1839 01.2For 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.1Copyrig
16、ht ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.4 supplied formthe condition of the foam productwhen received from the supplier by the end user.3.1.4.1 solidthe foam is in a uniform solid form, such asa slab, plate, or block.3.1.4.2 liqu
17、idtwo liquid components (base and activator)that can be mixed by the end user to produce a rigid, unicellularfoam slab.3.1.5 ungradedfoam that does not fit into one of the fivegrades specified in 3.1 because of the foam not meeting one ormore of the physical or mechanical requirements of Section 4.4
18、. Physical 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 extraneou
19、s matter, 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 its volume to beuniform and free from obvious extraneous matter or particulatedebris.4.2.3 Solid Final FormThe
20、solid 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 pr
21、ocedures 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
22、 shall meetthis requirement.4.5 Dimensional StabilityThe material in the solid finalform shall have an average percentage thickness of change lessthan 1.0 %, when tested according to the method described in8.3.4.6 Compressive StrengthThe material in the solid finalform shall meet the compressive str
23、ength requirements given inTable 3, when tested according to the method described in 8.4.All specimens shall meet this requirement. The values in Table3 are stated at 616.0 kg/m3(61.0 lbm/ft3) around each gradesnominal density.4.7 Compressive ModulusThe material in the solid finalform shall meet the
24、 compressive modulus requirements givenin Table 4, when tested according to the method described in8.4. All specimens shall meet this requirement. The values inTable 4 are stated at 616.0 kg/m3(61.0 lbm/ft3) around eachgrades nominal density.4.8 Shear StrengthThe material in the solid final formshal
25、l meet the shear strength requirements given in Table 5,when tested according to the method described in 8.5. Allspecimens shall meet this requirement. The values in Table 5are stated at 616.0 kg/m3(61.0 lbm/ft3) around each gradesnominal density.4.9 Shear ModulusThe material in the solid final form
26、shall meet the shear modulus requirements given in Table 6,when tested according to the method described in 8.5. Allspecimens shall meet this requirement. The values in Table 6are stated at 616.0 kg/m3(61.0 lbm/ft3) around each gradesnominal density.4.10 Screw PulloutThe material in the solid final
27、formshall meet the screw pullout requirements given in Table 7,when tested according to the method described in 8.6. Allspecimens shall meet this requirement.5. Significance and Use5.1 This specification describes the compositional require-ments, physical requirements, mechanical requirements, andte
28、st methods for rigid unicellular polyurethane foam for use intesting orthopedic devices or instruments.5.2 This foam described in this specification is not intendedto replicate the mechanical properties of human or animalbone. The requirements of this specification are intended toTABLE 1 Requirement
29、s 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.)Void diameter (measured parallel toslabs transverse plane)Larger than 6.35 mm (0.250
30、in.) None allowed in any gradeBetween 3.18 mm (0.125 in.)and 6.35 mm (0.250 in.)No more than 1 allowed per 230cm2(36 in.2) surface area for Grades10, 12, and 15. None allowed inGrades 20 and 40.Between 1.57 mm (0.062 in.)and 3.18 mm (0.125 in.)No more than 6 allowed per 230cm2(36 in.2) surface area
31、for Grades10, 12, and 15. No more than 3allowed in Grades 20 and 40.Cracks None allowedNonuniform areas 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/
32、ft3)Maximum Density,kg/m3(lbm/ft3)10 144.2 (9.0) 176.2 (11.0)12 176.2 (11.0) 208.2 (13.0)15 224.3 (14.0) 256.3 (16.0)20 304.4 (19.0) 336.4 (21.0)40 624.7 (39.0) 656.8 (41.0)TABLE 3 Requirements for Compressive StrengthGradeMinimum CompressiveStrength, kPa (psi)Maximum CompressiveStrength, kPa (psi)1
33、0 2095 (304) 2895 (420)12 2895 (420) 3790 (550)15 4280 (620) 5315 (770)20 7000 (1015) 8245 (1195)40 22 410 (3250) 24 300 (3525)F 1839 01 (2007)2provide a consistent and uniform material with properties onthe order of human cancellous bone to use as a test mediumwhen testing various orthopedic device
34、s, such as bone screws.6. Apparatus6.1 Analytical Balance or Scalecapable of weighing foamspecimens to the nearest 60.1 %.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 maintaining 121 6
35、 2.8C (250 6 5F) for 24 h.6.4 Desiccatorcontaining desiccant with high affinity forwater vapor (anhydrous calcium chloride or equivalent).6.5 Vacuumcapable of applying a vacuum pressure of 508mm (20 in.) of mercury to foam specimen for dimensionalstability test.6.6 A testing machine and load cell co
36、nforming to PracticesE4and capable of applying tensile and compressive loads at aconstant 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. Test specimens are r
37、equired 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 described and spec
38、ifiedin 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:8.2.1 Prepare thre
39、e 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 Dimensional Stab
40、ility: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 the location of th
41、e 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 2 hminimum at 121 6 2.8C (250 6 5F). Remove the assemblyand all
42、ow to cool to 49C (120F) or less while maintaining thevacuum.8.3.4 Recondition and remeasure the thickness at themarked location in accordance with 8.3.2. Calculate the per-cent thickness change.8.3.5 Calculate the average percent thickness change of thethree specimens.8.4 Determination of Compressi
43、ve 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
44、 h prior totesting.8.4.2 Test in accordance with Test Method D 1621 at 24 62.8C (75 6 5F). The specimens shall be oriented such thatthe axis of the compressive load is applied parallel to the foamrise direction.8.4.3 Determine the compressive strength using ProcedureA of Test Method D 1621 and the m
45、aximum compressivemodulus for each specimen.8.4.4 Calculate the average compressive strength and modu-lus of the five specimens.8.5 Determination of Shear Strength and Modulus:TABLE 4 Requirements for Compressive ModulusGradeMinimum CompressiveModulus, kPa (psi)Maximum CompressiveModulus, kPa (psi)1
46、0 56 300 (8165) 76 700 (11 125)12 76 700 (11 125) 99 200 (14 390)15 111 200 (16 130) 136 650 (19 820)20 178 100 (25 830) 207 800 (30 140)40 539 600 (78 260) 582 800 (84 530)TABLE 5 Requirements for Shear StrengthGradeMinimum Shear Strength,kPa (psi)Maximum Shear Strength,kPa (psi)10 1650 (240) 2170
47、(315)12 2170 (315) 2725 (395)15 3000 (435) 3620 (525)20 4590 (665) 5275 (765)40 12 340 (1790) 13 240 (1920)TABLE 6 Requirements for Shear ModulusGradeMinimum Shear Modulus,kPa (psi)Maximum Shear Modulus,kPa (psi)10 20 820 (3020) 27 680 (4015)12 27 680 (4015) 35 100 (5090)15 39 000 (5655) 47 130 (683
48、5)20 60 160 (8725) 69 400 (10 060)40 167 170 (24 245) 179 470 (26 030)TABLE 7 Requirements for Screw PulloutGradeMinimum Pullout,N (lb)Maximum Pullout,N (lb)10 335 (75) 415 (95)12 400 (90) 545 (125)15 485 (110) 675 (150)20 670 (150) 800 (180)40 2455 (550) 2755 (620)F 1839 01 (2007)38.5.1 Prepare fiv
49、e specimens, 76.2 by 25.4 by 6.35 mm (3by 1 by 0.25 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 5F) for 3 h beforetesting.8.5.2 Bond the edges of the foam specimen directly to theshear plates with an appropriate adhesive, such as an epoxy, sothat the foam rise direction is perpendicular to the plane ofmaximum shear stress.8.5.3 Test in accordance with Test Method C 273.8.5.4 Determin
