1、Designation: D 7138 08An American National StandardStandard Test Method toDetermine Melting Temperature of Synthetic Fibers1This standard is issued under the fixed designation D 7138; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 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, o
3、r 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 an
4、d 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, t
5、he 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
6、 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 Stand
7、ard:2D 123 Terminology Relating to TextilesD 276 Test Methods for Identification of Fibers in TextilesD 1776 Practice for Conditioning and Testing TextilesD 2257 Test Method for Extractable Matter in TextilesD 2258 Practice for Sampling Yarn for TestingD 3333 Practice for Sampling Manufactured Stapl
8、e 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, seeTermino
9、logy D 123.4. 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 spe
10、cimen 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 wh
11、ich 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,
12、 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
13、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.5.2.1 If there are differences of practical significance be-tween reported test results for two or more laboratories,
14、perform comparative testing to determine if there is a statistical1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.51 on Conditioning and,Chemical and Thermal Properties.Current edition approved July 1, 2008. Published
15、August 2008. Originallyapproved in 2007. Last previous edition approved in 2007 as D 7138 - 07.2For 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 Documen
16、t Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.bias between them, using competent statistical assistance. As aminimum, use the samples for such a comparative test that areas homogeneous as possible,
17、 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 unpaired data, at a prob-ability level chosen prio
18、r to the testing series. If bias is found,either its cause must be found and corrected, or future testresults for that material must be adjusted in consideration of theknown bias.5.3 This test method is suitable for quality control testing ofsynthetic fibers and product comparisons of different fibe
19、rs bymanufacturers, retailers, and users.5.4 If the test method is used to identify fiber material type,it is important to test a known reference material at the samelaboratory with the same test method to confirm the fiberidentification. In addition, since some fiber types have similarmelting tempe
20、ratures or overlapping melting temperatureranges as show in Table X1.1, secondary methods for fiberidentification as described in Test Methods D 276 will berequired to make fiber identifications.6. Apparatus6.1 Apparatus for Method 1, using a DSC instrument:6.2 Apparatus for Method 2:6.2.1 Test Unit
21、 ConfigurationApparatus used consists ofan electrically heated stage which has a temperature range from20C (68F) to 300C (572F) or at least 10C (18F) above thehighest melting temperature to be measured. See Fig. X1.1 fora typical apparatus.6.2.1.1 The adjustment mechanism shall be able to controlthe
22、 heat input into the stage.6.2.1.2 Thermometer for measuring temperature shall beaccurate to +0.5C (+1F).6.2.1.3 The device shall have a low powered magnifyingglass to permit visual examination.6.2.1.4 The device shall have a top and bottom microcoverglass. The top glass shall fit directly over the
23、bottom glass sothat the fiber specimen rests between the microcovers.6.2.2 Soxhlet extraction device. See Fig. X1.2.7. Preparation of Apparatus7.1 Lot Sample:As a lot sample for acceptance testing, take at random thenumber of laboratory sampling units as directed in an appli-cable material specifica
24、tion or other agreement between thepurchaser and the supplier. In the absence of a materialspecification or other agreement, use Practice D 2258 orPractice D 3333, as applicable. Consider containers, such ascartons, bales or other shipping containers to be the primarysampling units.7.2 Laboratory Sa
25、mple Unit:As a laboratory sampling unit for acceptance testing, take asdirected in Practice D 2258 or Practice D 3333, as applicable.If the fiber sample requires cleaning using a Soxhlet extractorproceed to 7.2.1. If cleaning using a Soxhlet extractor is notrequired proceed to 7.3.7.2.1 Place sample
26、 in a Soxhlet extractor (see Fig. X1.2)and perform twenty extractions using a chloroform, USPreagent. Follow extraction procedure in D 2257. Other solventssuch as methanol, ethanol or isopropyl alcohol may be used ifthey are found to be effective in removing fiber finishes andcoatings.7.2.2 Dry samp
27、les and return to equilibrium in accordancewith D 1776.7.3 Test Specimens:7.3.1 Method 1:7.3.1.1 DSC Sample PreparationCut the samples intovery small pieces with scissors and puta5to7mgspecimeninto the aluminum pan. Make a small hole on the lid with aneedle and close the pan with the help of a sampl
28、e crimper.Make another sample, which will be used as the referencesample by closing an empty pan with lid.7.3.1.2 Prepare five specimens and five references to per-form five replicates.7.3.2 Method 2:7.3.2.1 From each laboratory sampling unit, cut five fibersamples into specimens having a length of
29、approximately 2mm (.0625 in).7.3.2.2 Prepare the five specimens to perform five repli-cates.8. Calibration8.1 Follow the manufacturers instructions to calibrate themelting temperature apparatus (see Appendix X1).8.2 Verify the melting temperature apparatus performanceby using fiber of a known meltin
30、g temperature (see TableX1.1).NOTE 1 Use a fiber having a melting temperature similar to thespecimen to be tested (see Table X1.1).NOTE 2Avoid using a fiber with a wide melting temperature range asthe verification fiber (see Table X1.1).8.2.1 Verification is achieved when the melting temperatureof t
31、he verification fiber used is within +1C (+2F) of its knownvalue.9. Test Procedure9.1 Procedure for Method 1:9.1.1 Put the specimen and the reference in the designatedheating blocks (in accordance with the instrument manufactur-ers manual) inside the heater chamber. Close the chamber, andstart heati
32、ng at the rate of 10C/min to approximately 50Cabove the melting point of the fiber being tested in accordancewith Table X1.1.9.1.2 Record the temperature. Cool the chamber, and repeatthe measurement on a new specimen until five specimens arecompleted.9.2 Procedure for Method 2:9.2.1 Place a specimen
33、 consisting of a sufficient quantity offibers to observe specimen melting, approximately 50 cutfibers, on the bottom microcover glass of the test apparatus andcover with the top micro glass.9.2.2 If the fiber melting temperature is known, set the dialof the test apparatus to a temperature 15C (+27F)
34、 below theanticipated melting temperature. Proceed to 9.2.5.D71380829.2.3 If the melting temperature is not known beforetesting, it can be determined by using the following approach:9.2.3.1 Place the specimen in the apparatus and elevate thetemperature to 140C (284F). If the specimen melts, test the
35、next specimen, after cool down of the apparatus, at a tempera-ture 20C (36F) lower. If the specimen does not melt, proceedto 9.2.5.9.2.3.2 Continue this process until the fiber does not melt.9.2.4 Gradually raise the temperature at 3C (+5F) perminute until the fiber demonstrates melting.9.2.5 Observ
36、e the specimen using the magnifying glass.9.2.6 Read the temperature to nearest degree C (F) on thetest apparatus when it is observed that the solid demonstrates aliquid flow.10. Final Test Report10.1 Report that the melting temperature of fibers wasdetermined as directed in Test Method D 7138. Indi
37、catewhether Method 1 or Method 2 was used to determine themelting temperature. Describe the material or product sampledand the method of sampling used.10.2 Report the following information for the laboratorysampling unit and for the lot as applicable to a materialspecification or contract order. For
38、 Method 1, if a fiber blendsample is tested, report the results for each fiber type in theblend sample.10.2.1 Report the melting temperature of each of the fivereplicates to the nearest degree C (F).10.2.2 Calculate and report the average melting temperatureof the five replicates to the nearest degr
39、ee C (F).11. Precision and Bias11.1 Precision and Bias for Method 1:11.2 Precision and Bias for Method 2:11.2.1 PrecisionThe repeatability standard deviation hasbeen determined to be 1.3C for a polyester sample and 2.1Cfor a nylon sample. The 95 % confidence limit for the polyestersample is 240 6 2C
40、 and for the 66 nylon sample is 238 63C. The reproducibility of this test method is being deter-mined and will be available on or before January 31, 2009.11.2.2 BiasNo information can be presented on the biasof the procedure in Test Method D 7138 because no fibermaterial having an accepted reference
41、 value is available. It maybe possible to determine bias using non-fiber crystallinematerials, and this will be addressed in later editions.12. Keywords12.1 differential scanning calorimetry; melting; syntheticfibersAPPENDIXX1. Melting Temperature Apparatus and Typical Fiber Melting TemperaturesX1.1
42、 The purpose of the melting or apparent meltingtemperatures and melting temperature ranges listed in TableX1.1 is to assist in establishing the starting temperature for afiber melting or apparent temperature determination when thefiber type is known. It is not known whether the listed meltingtempera
43、tures were determined by Method 1 or Method 2.TABLE X1.1 List of Approximate Fiber Melting or ApparentMelting Temperatures and Temperature RangesA,B,CFiber Type Melting Temperature, CVinyon HH Softens at 85PVC About 100Polyethylene 135 - 160Polypropylene 164 - 170Chlorofibre 162 - 167Saran 166 and 1
44、70Nytril 176Modacrylic 184Polyamid (Nylon) 6 216 and 219Spandex 230Polyurethane 230 - 260Polyamide (Nylon) 6-6 238 - 260Polyester 240 - 250Polyacrylonitrile 235 - 330Acetate 260Polycarbonate 294Triacetate 288 and 300Polytetrafluoroethylene 327AIn some cases degradation takes place prior to or instea
45、d of melting.BRae, Alex and Rollo, Bruce (1973), The WIRA Textile Data Book, Wira, Leeds.CTest Methods D 276 Standard Test Methods for Identification of Fibers inTextiles.D7138083X1.2 ApparatusSee Fig. X1.1 and Fig. X1.2.FIG. X1.1 Melting Temperature ApparatusFIG. X1.2 Soxhlet Extraction ApparatusD7
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49、ommittee 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).D7138085
