ASTM_D_3576_-_20.pdf

Designation:D357620Standard 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 revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()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 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 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 of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE1The annex to ISO 2896 is technically equivalent to this testmethod.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD2842 Test Method for Water Absorption of Rigid CellularPlasticsD6226 Test Method for Open Cell Content of Rigid CellularPlasticsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standard:ISO 2896 Cellular Plastics,RigidDetermination of WaterAbsorption33.Terminology3.1 Terms used in this standard are defined in accordancewith Terminology D883,unless otherwise specified.For termsrelating to precision and bias and associated issues,the termsused in this standard are defined in accordance with Terminol-ogy E456.4.Summary of Test Method4.1 Procedure AThe cellular plastic specimen is cut to notmore 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 cell size bymathematical derivation.4.2 Procedure BThe cellular plastic specimen is sliced toprovide a smooth surface.The cell walls are accented by theuse of a marking pen or marking ink.The average chord lengthis obtained by counting the cell wall intersections and convert-ing this value to average cell 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 D2842 and Test Method D6226 requires knowledge ofsurface cell volume,which uses cell size values in thecalculations.1This 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 Dec.1,2020.Published December 2020.Originallyapproved in 1977.Last previous edition approved in 2015 as D3576-15.DOI:10.1520/D3576-20.2For 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.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.15.2 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 concerned there may be sign