1、Designation: D3576 04 (Reapproved 2010)Standard Test Method forCell Size of Rigid Cellular Plastics1This standard is issued under the fixed designation D3576; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio
2、n. 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 covers the determination of the appar-ent cell size of rigid cellular plastics by counting the number ofcell-wall
3、 intersections in a specified distance.1.2 Procedure A requires the preparation of a thin slice, notmore than one half the average cell diameter in thickness, thatis mechanically stable. For most rigid cellular plastics thislimits the test method to materials with an average cell size ofat least 0.2
4、 mm.1.3 Procedure B is intended for use with materials whosefriable nature makes it difficult to obtain a thin slice forviewing.1.4 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all o
5、f 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.NOTE 1The annex to ISO 2896 is technically equivalent to this test
6、method.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD2842 Test Method for Water Absorption of Rigid CellularPlasticsD2856 Test Method for Open-Cell Content of Rigid Cellu-lar Plastics by the Air Pycnometer3E691 Practice for Conducting an Interlaboratory Study toDet
7、ermine the Precision of a Test Method2.2 ISO Standard:ISO 2896 Cellular Plastics, RigidDetermination of WaterAbsorption43. Terminology3.1 Definitions of terms applicable to this test method aregiven in Terminology D883.4. Summary of Test Method4.1 Procedure AThe cellular plastic specimen is cut to n
8、otmore than one half the average cell diameter in thickness on aslicer and the shadowgraph is projected on a screen by the useof a cell-size scale slide assembly and a projector. The averagechord length is obtained by counting the cells on cell-wallintersections and converting this value to average
9、cell size bymathematical derivation.4.2 Procedure B The cellular plastic specimen is sliced toprovide a smooth surface. The cell walls are accented by theuse of a marking pen. The average chord length is obtained bycounting the cell wall intersections and converting this value toaverage cell size by
10、 mathematical derivation.5. Significance and Use5.1 Several physical properties of rigid cellular plastics aredependent on cell size and cell orientation. Measuring waterabsorption and open-cell content in accordance with TestMethod D2842 and Test Method D2856 requires knowledge ofsurface cell volum
11、e, which uses cell size values in thecalculations.5.2 This test method provides an apparent cell size becauseit assumes that there is no measurable edge to edge or top tobottom variation in average cell size and that the cell sizedistribution about the average cell size is normal. If the analystis c
12、oncerned there may be significant variation in either theaverage cell size or the cell size distribution more detailedanalysis may be required.5.3 Before proceeding with this test method, referenceshould be made to the specification of the material being tested.Any test specimen preparation, conditi
13、oning, dimensions, ortesting parameters, or a combination thereof, covered in thematerials specification shall take precedence over those men-tioned in this test method. If there are no material specifica-tions, then the default conditions apply.1This test method is under the jurisdiction of ASTM Co
14、mmittee D20 on Plasticsand is the direct responsibility of Subcommittee D20.22 on Cellular Materials -Plastics and Elastomers.Current edition approved April 15, 2010. Published June 2010. Originallyapproved in 1977. Last previous edition approved in 2004 as D3576 - 04. DOI:10.1520/D3576-04R10.2For r
15、eferenced 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.3Withdrawn. The last approved version of this historical standard i
16、s referencedon www.astm.org.4Available 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 19428-2959, United States.FIG. 1 Razor Blade Cell Size S
17、pecimen SlicerFIG. 2 Cell Size Scale Slide AssemblyD3576 04 (2010)26. Apparatus6.1 The apparatus required to perform the test as defined byProcedure A is listed as follows:6.1.1 Cell Size Specimen Slicer5Cutting blade apparatuscapable of slicing thin specimens (0.02 mm) for cell sizeviewing. Fig. 1
18、shows an acceptable alternative slicing appa-ratus.6.1.2 Cell Size ProjectorConventional 35-mm slide pro-jector that accepts standard 50 by 50-mm (2 by 2-in.) slides.6.1.3 Cell Size Scale Slide Assembly, consisting of twopieces of slide glass hinged by tape along one edge, betweenwhich a calibrated
19、scale (30 mm in length) printed on a thinplastic sheet is placed (see Fig. 2).6.2 The apparatus required to perform the test as defined byProcedure B is listed as follows:6.2.1 Cell Size Specimen Slicer5Cutting blade apparatuscapable of providing a smooth surface.6.2.2 Optical Magnification System,
20、capable of 5 to 253magnification with a calibrated scale of the appropriate length.6.2.3 Highlighting Market, that does not contain a solventwhich will attack the polymer system. The ink used shouldcontrast with the color of the foam.7. Sampling7.1 Generally one specimen is sufficient to determine t
21、heapparent cell size of a sample.7.2 The number of samples may be dictated by the end-usedata needed.8. Procedures8.1 Procedure A:8.1.1 Cut a specimen 50 by 50 mm by thickness (2 by 2 in.by thickness) from the sample in the area to be tested.8.1.2 Prepare the cell size viewing specimen by cutting at
22、hin slice (less than monocellular) from one of the cut surfacesof the specimen. (Slice thickness should be as thin as practi-cable; so that a shadowgraph will not be occluded by overlap-ping cell walls. Optimum slice thickness will vary with theaverage cell size of the foam, with smaller cell foams
23、requiringthinner slices.)NOTE 2One cell size measurement will provide a representativeapparent cell size for cellular plastics having symmetric cells of relativelyuniform size. However, if the cell size in the three normal directions issuspected of varying by a value greater than the precision of th
24、is testmethod, all three directions should be measured and reported for maxi-mum accuracy. An acceptable procedure, in this case, is to determine thecell size in two planes perpendicular to each other. The size of the cells inthe three normal directions can then be compared and reported separatelyif
25、 desired.8.1.3 Insert the thin-sliced foam specimen into the cell sizeslide assembly. Position the zero on the grid line at the top ofthe area to be measured. Reassemble the slide.8.1.4 Insert the slide assembly into the projector. Focus theprojector on the wall or screen so that a sharp image shado
26、w-graph results.8.1.5 Count the number of cell walls that intersect thereference line.68.1.6 Determine the average cell chord length, t. Divide thelength of the reference line by the number of cells counted toobtain the average chord length, t. The length of the referenceline is expressed in millime
27、tres.8.2 Procedure B:8.2.1 Cut a 25-mm (1-in.) section across the width of thesample.8.2.2 Identify the length (L) and width (W) direction in themiddle of the strip.8.2.3 Cut a 25-mm (1-in.) section with the L and W markingfrom the center of the strip giving a specimen of 25 by 25 mmby thickness (1
28、by 1 in. by thickness).8.2.4 Shave adjacent planes of the sample giving exposedcut cells in the L, W, and thickness (T) directions (see Note 2).8.2.5 Coat the shaved planes with the marker with a uniformcoating in such a manner that additional cell walls are notbroken.8.2.6 Place the sample in a man
29、ner to observe cells in the Tdirection. The sample holder should be of sufficient size andintegrity so as to hold the sample steady during measurement(see Note 3).NOTE 3For samples with an apparent cell size of 0.3 mm or smallerthe cell size may be measured by the use of a B rigid cellular plastics9
30、Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D20-1185.TABLE 1 Precision Data Summary, Procedure AMaterialNominalThickness, in.Average CellSize,mm% grA% gRBrCRDNumber ofLaboratoriesin ResearchReportExtruded Polystyrene Foam 0.7
31、5 0.36 5.7 9.3 16.3 26.4 4Extruded Polystyrene Foam 2 0.79 7.3 12.3 20.7 34.7 4Extruded Polystyrene Foam 6.5 1.6 5.3 15.1 14.9 42.8 4Polyisocyanurate Foam (Glass FibersReinforced)2 0.33 9.4 18.3 26.6 51.8 3Phenolic Foam 1 0.37 17.2 17.4 48.7 49.2 3Agris the within-laboratory coefficient of variation
32、 of the average.BgRis the between-laboratories coefficient of variation of the average.Cr is the within-laboratory repeatability limit = 2.8 gr.DR is the between-laboratories reproducibility limit = 2.8 gR.TABLE 2 Precision Data Summary, Procedure BMaterialNominalThickness, in.Average CellSize,mm% g
33、rA% gRBrCRDNumber ofLaboratories inResearch ReportExtruded Polystyrene Foam 0.75 0.35 8.7 11.6 24.8 32.9 6Extruded Polystyrene Foam 2 0.74 6.2 19.4 17.47 54.9 6Extruded Polystyrene Foam 6.5 1.7 5.2 15.1 14.7 42.7 5Polyisocyanurate Foam (Glass FibersReinforced)2 0.39 10.3 31.0 29.1 87.7 7Polyurethane
34、 Foam 1 0.37 10.5 32.1 29.7 90.8 6Phenolic Foam 1 0.13 8.7 14.8 24.5 41.9 3Agris the within-laboratory coefficient of variation of the average.BgRis the between-laboratories coefficient of variation of the average.Cr is the within-laboratory repeatability limit = 2.8 gr.DR is the between-laboratorie
35、s reproducibility limit = 2.8 gR.D3576 04 (2010)4APPENDIX(Nonmandatory Information)X1. DERIVATION OF CELL SIZEX1.1 Assumptions made in this derivation are that the cellshape is spherical and that the cells are relatively uniform withrespect to size.X1.2 Subsection 8.1.6 of this test method describes
36、 theprocedure for determining t, the average measured chordlength of the randomly truncated cells. The relationship be-tween t and the average cell diameter, d8, appearing at the planeof the cut surface, may be calculated as follows:X1.2.1 The mean value of the ordinates in the first quadrantfor any
37、 circle x2+ y2= r2is:y51/r!*0r=r22x2dx5pr/4 (X1.1)where:r = radius of the cell in the surface plane, andy= t/2.Therefore:t/25pr/4 (X1.2)Since r = d8/2 then:t5pd8/4 (X1.3)Rearrangement of Eq X1.3 yields:d85t/0.785 (X1.4)X1.3 The average cell diameter of the circular segments, d8,is related to the dia
38、meter of the sphere, d in the same manner.The average sphere diameter is larger than the average circularsegment diameter, d8, because the cells are randomly truncatedwith respect to depth at the plane of the specimen surface. Themean value of the chord length with respect to diameter (see EqX1.3) a
39、gain applies:d5d8/0.785 (X1.5)Combining Eq X1.4 and X1.5 yields:d5t/0.785!25t/0.616 (X1.6)5t1.623! (X1.7)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
40、 determination of the 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 reapprov
41、ed or withdrawn. Your 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 fee
42、l that your comments 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 repr
43、ints (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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D3576 04 (2010)5
