ASTM_D_7138_-_16.pdf

Designation:D713816An American National StandardStandard Test Method toDetermine Melting Temperature of Synthetic Fibers1This standard is issued under the fixed designation D7138;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.Scope1.1 Either of two test methods are used to determine themelting temperature of thermoplastic fibers,yarns,or threads.1.2 Method 1 can be used to determine melting tempera-tures for blends of multiple fiber material types.Method 2 canonly be used to determine the melting temperature of a singlefiber material type.1.2.1 Method 1,Differential Scanning Calorimetry(DSC),measures changes in heat capacity and will detect the glasstransition,the crystalline melting and endothermic thermaldegradation.1.2.2 Method 2,a visual determination of melting,deter-mines any change that visually appears as a transition from asolid to a liquid state.1.2.3 Due to the differences in what each test methodmeasures,the results from Method 1 and Method 2 cannot becompared.1.3 The values stated in either SI units or other units are tobe regarded separately.The values stated in each system are notexact equivalents;therefore,each system shall be used inde-pendently without combining values.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD276 Test Methods for Identification of Fibers in TextilesD1776 Practice for Conditioning and Testing TextilesD2257 Test Method for Extractable Matter in TextilesD2258 Practice for Sampling Yarn for TestingD3333 Practice for Sampling Manufactured Staple Fibers,Sliver,or Tow for Testing3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 melting temperature,nthe temperature or range oftemperatures at which a substance is observed to transition toa liquid-like state.3.1.2 For all other terminology related to textiles,seeTerminology D123.4.Summary of Test Method4.1 Method 1:4.1.1 A specimen of fiber and a reference sample arepositioned into the designated heating blocks of a DifferentialScanning Calorimetry(DSC)instrument.4.1.2 Use the DSC data to determine the fiber specimenmelting temperature.4.2 Method 2:4.2.1 A specimen of fiber is positioned in a melting tem-perature device.4.2.2 The temperature of the device is raised until the fiberspecimen reaches its melting temperature as determined byvisual observation.5.Significance and Use5.1 Either of these two test methods is used to determine thetemperature at which a synthetic fiber specimen changes froma solid to a liquid-like state.5.1.1 Synthetic fibers may be either amorphous or semi-crystalline thermoplastics or thermosets.Synthetic fibers maychange from the solid to a liquid-like state on heating becauseof the glass transition of amorphous polymers,the melting ofcrystalline regions of semi-crystalline polymers,or at the onsetof degradation.Thermoplastic fibers consist of crystalline andamorphous regions and may be manufactured with a range ofmolecular weights.The amorphous and crystalline fiber struc-ture and variable molecular weight can lead to a meltingtemperature range instead of a discreet melting point(see TableX1.1).5.2 This test method is considered satisfactory for accep-tance testing of commercial shipments.1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.51 on Conditioning,Chemicaland Thermal Properties.Current edition approved Jan.1,2016.Published February 2016.Originallyapproved in 2007.Last previous edition approved in 2008 as D7138-08.DOI:10.1520/D7138-16.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2.1 If there are differences of practical significance be-tween reported test results for two or more laboratories,perform comparative testing to determine if there is a statisticalbias between them,using competent statistical assistance.As aminimum,use the samples for such a comparative test that areas homogeneous as possible,drawn from the same lot ofmaterial as the samples that resulted in disparate results duringinitial testing and randomly assigned in equal numbers to eachlaboratory.Compare the test results from the laboratoriesinvolved using a statistical test for unpa