1、Designation: D 3576 04Standard Test Method forCell Size of Rigid Cellular Plastics1This standard is issued under the fixed designation D 3576; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in p
2、arentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of the appar-ent cell size of rigid cellular plastics by counting the number ofcell-wall intersections
3、 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 mm.1.3 Proced
4、ure 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 as thestandard. The values given in brackets are for information only.1.5 This standard does not purport to address all of thesafety
5、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 testmethod.2. Re
6、ferenced Documents2.1 ASTM Standards:2D 883 Terminology Relating to PlasticsD 2842 Test Method for WaterAbsorption of Rigid CellularPlasticsD 2856 Test Method for Open-Cell Content of Rigid Cel-lular Plastics by the Air PycnometerE 691 Practice for Conducting an Interlaboratory Study toDetermine the
7、 Precision of a Test Method2.2 ISO Standard:ISO 2896 Cellular Plastics, RigidDetermination of WaterAbsorption33. Terminology3.1 Definitions:3.1.1 Definitions of terms applicable to this test method aregiven in Terminology D 883.4. Summary of Test Method4.1 Procedure A The cellular plastic specimen i
8、s cut tonot more than one half the average cell diameter in thicknesson a slicer and the shadowgraph is projected on a screen by theuse of a cell-size scale slide assembly and a projector. Theaverage chord length is obtained by counting the cells oncell-wall intersections and converting this value t
9、o average cellsize by mathematical 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 ce
10、ll size by 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 D 2842 and Test Method D 2856 requires knowledgeof surfac
11、e cell volume, 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
12、 analystis concerned 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 preparat
13、ion, conditioning, dimensions, or1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.22 on Cellular Materials -Plastics and Elastomers.Current edition approved July 1, 2004. Published July 2004. Originally approvedin 1977.
14、 Last previous edition approved in 1998 as D 3576 - 98.2For 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.3Avail
15、able from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.testing parameters
16、, 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.6. Apparatus6.1 The apparatus required to perform the test as defined byProcedure A is listed
17、 as follows:6.1.1 Cell Size Specimen Slicer4Cutting blade apparatuscapable of slicing thin specimens (0.02 mm) for cell sizeviewing. Fig. 1 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. sli
18、des.6.1.3 Cell Size Scale Slide Assembly, consisting of twopieces of slide glass5hinged by tape along one edge, betweenwhich a calibrated 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
19、 follows:6.2.1 Cell Size Specimen Slicer4Cutting blade apparatuscapable of providing a smooth surface.6.2.2 Optical Magnification System, 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
20、 polymer system. The ink used shouldcontrast with the color of the foam.7. Sampling7.1 Generally one specimen is sufficient to determine theapparent 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
21、 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 athin 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 b
22、e occluded by overlap-ping cell walls. Optimum slice thickness will vary with theaverage cell size of the foam, with smaller cell foams requiringthinner slices.)NOTE 2One cell size measurement will provide a representativeapparent cell size for cellular plastics having symmetric cells of relativelyu
23、niform size. However, if the cell size in the three normal directions issuspected of varying by a value greater than the precision of this 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 tw
24、o planes perpendicular to each other. The size of the cells inthe three normal directions can then be compared and reported separatelyif 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. Reass
25、emble the slide.8.1.4 Insert the slide assembly into the projector. Focus theprojector on the wall or screen so that a sharp image shadow-graph results.4Hobart Model 610-1, an electrically operated slicer, available from the HobartCorp., 701 S. Ridge Ave., Troy, OH 45374.5Cell size grid decals can b
26、e obtained from ASTM Headquarters.FIG. 1 Razor Blade Cell Size Specimen SlicerD 3576 0428.1.5 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
27、chord length, t. The length of the referenceline is expressed in millimetres.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
28、center of the strip giving a specimen of 25 by 25 mmby thickness 1 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 a
29、dditional cell walls are notbroken.8.2.6 Place the sample in a manner 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 ce
30、ll size may be measured by the use of a B rigid cellular plastics9Supporting data are available from ASTM Headquarters, Request RR: D20-1185.TABLE 1 Precision Data Summary, Procedure AMaterialNominalThickness, in.Average CellSize,mm% grA% gRBrCRDNumber ofLaboratoriesin ResearchReportExtruded Polysty
31、rene Foam 0.75 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
32、 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-laboratories reproducibility limit = 2.8 gR.TABLE 2 Precision Data Summary, Procedure BMaterialNominalThickness, in.Average C
33、ellSize,mm% grA% 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
34、7Polyurethane 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 betwee
35、n-laboratories reproducibility limit = 2.8 gR.D 3576 044APPENDIX(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 de
36、scribes 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 quadrant
37、for any 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
38、the diameter 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 Eq
39、X1.3) again 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)SUMMARY OF CHANGESThis section identifies the location of selected changes to this test method. For the convenience of the user,Committee D20 has highlighted those changes that may impact
40、the use of this test method. This section may alsoinclude descriptions of the changes or reasons for the changes, or both.D 3576 04:(1) Corrected supplier address in Footnote4.(2) Corrected Eq X1.1.D 3576 98:(1) Revised Significance and Use section to add a reference tomaterial specifications.(2) Ad
41、ded a Keyword section.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 the validity of any such patent rights, and the riskof infringeme
42、nt 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. Your comments are invited either for revision of this standard or
43、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 comments have not received a fair hearing you shouldmake your views kno
44、wn 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).D 3576 045
