1、Designation:D150518Standard Test Method forDensity of Plastics by the Density-Gradient Technique1This standard is issued under the fixed designation D1505;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A nu
2、mber in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 This test method covers the determination of the densit
3、yof solid plastics.1.2 This test method is based on observing the level towhich a test specimen sinks in a liquid column exhibiting adensity gradient,in comparison with standards of knowndensity.NOTE1This test method is equivalent to ISO 1183-2.1.3 The values stated in SI units are to be regarded as
4、 thestandard.1.4 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 prio
5、r to use.1.5 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 TechnicalBar
6、riers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD2839 Practice for Use of a Melt Index Strand for Deter-mining Density of PolyethyleneD4703 Practice for Compression Molding ThermoplasticMaterials into Test Specimens,Plaques,or SheetsE691 Pr
7、actice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE2935 Practice for Conducting Equivalence Testing inLaboratory Applications2.2 ISO Standard:ISO 1183-2Methods for Determining the Density andRelative Density of Noncellular Plastics33.Terminology3.1 Refer to Ter
8、minology D883 for definitions of otherterms relating to this test method.3.2 Definitions:3.2.1 density of plasticsthe weight per unit volume ofmaterial at 23C,expressed as follows:D23C,g/cm3(1)NOTE2Density is to be distinguished from specific gravity,which isthe ratio of the weight of a given volume
9、 of the material to that of an equalvolume of water at a stated temperature.4.Significance and Use4.1 The density of a solid is a conveniently measurableproperty which is frequently useful as a means of followingphysical changes in a sample,as an indication of uniformityamong samples,and a means of
10、identification.4.2 This test method is designed to yield results accurate tobetter than 0.05%.NOTE3Where accuracy of 0.05%or better is desired,the gradienttube shall be constructed so that vertical distances of 1 mm shall representdensity differences no greater than 0.0001 g/cm.3The sensitivity of t
11、hecolumn is then 0.0001 g/cm3mm.Where less accuracy is needed,thegradient tube shall be constructed to any required sensitivity.5.Apparatus5.1 Density-Gradient TubeA suitable graduate withground-glass stopper.45.2 Constant-Temperature BathA means of controllingthe temperature of the liquid in the tu
12、be at 23 6 0.1C.Athermostatted water jacket around the tube is a satisfactory andconvenient method of achieving this.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.70 on Analytical Methods(Section D20.70.01).Current e
13、dition approved April 1,2018.Published April 2018.Originallyapproved in 1957.Last previous edition approved in 2010 as D1505-10.DOI:10.1520/D1505-18.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards
14、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.4Tubes similar to those described in Refs(1)and(2)may also be used.*A Summary of Changes section
15、 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 Princip
16、les for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 5.3 Glass FloatsA number of calibrated glass floats cov-ering the density range to be studied and approximately evenlydistributed throughout this range.5.4 Pycnometer,for use in determining the densities of thestandard floats.5.5 Liquids,suitable for the preparation of a density gradi-ent(Table 1).NOTE4It is very important that none of th
