1、Designation: E1545 11Standard Test Method forAssignment of the Glass Transition Temperature byThermomechanical Analysis1This standard is issued under the fixed designation E1545; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、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 This test method describes procedures for the assign-ment of the glass transition temperature of materials on
3、heatingusing thermomechanical measurements under compressionexperimental conditions.1.2 This test method is applicable to amorphous or topartially crystalline materials that are sufficiently rigid belowthe glass transition to inhibit indentation by the sensing probe.1.3 The normal operating temperat
4、ure range is from 100to 600 C. This temperature range may be extended dependingupon the instrumentation used.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This test method is related to ISO 11359-2. ISO 11359-2addition
5、ally covers the determination of coefficient of linearthermal expansion not covered by this test method. This testmethod is related to IEC 61006 but uses a slower heating rate.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsib
6、ility 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. Specific precau-tionary statements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal
7、Analysis and Rhe-ologyE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1142 Terminology Relating to Thermophysical PropertiesE1363 Test Method for Temperature Calibration of Ther-momechanical Analyzers2.2 Other Standard:ISO 11359-2 PlasticsThermomechan
8、icalAnalysis (TMA) Part 2: Determination of Coefficient of Linear ThermalExpansion and Glass Transition Temperature3IEC 61006 Methods of Test for the Determination of theGlass Transition Temperature of Electrical Insulating Ma-terials43. Terminology3.1 DefinitionsThe following terms are applicable t
9、o thistest method and can be found in Terminologies E473 andE1142: thermomechanical analysis (TMA), thermomechanicalmeasurement, thermodilatometry, glass transition, glass tran-sition temperature, and linear thermal expansion.4. Summary of Test Method4.1 This test method uses thermomechanical analys
10、is equip-ment (thermomechanical analyzer, dilatometer, or similar de-vice) to assign the change in dimension of a specimen observedwhen the material is subjected to a constant heating ratethrough its glass transition. This change in dimension associ-ated with the change from vitreous solid to amorph
11、ous liquid isobserved as movement of the sensing probe in direct contactwith the specimen and is recorded as a function of temperature.The intersection of the extrapolation of the slope of the probedisplacement curve before and after the transition is used todetermine the glass transition temperatur
12、e.5. Significance and Use5.1 The glass transition is dependent on the thermal historyof the material to be tested. For amorphous and semicrystallinematerials the assignment of the glass transition temperaturemay lead to important information about thermal history,processing conditions, stability, pr
13、ogress of chemical reactions,and mechanical and electrical behavior.5.2 Thermomechanical analysis provides a rapid means ofdetecting changes in hardness or linear expansion associatedwith the glass transition.1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and
14、 is the direct responsibility of Subcommittee E37.10 on Funda-mental, Statistical and Mechanical Properties.Current edition approved April 1, 2011. Published May 2011. Originallyapproved in 1993. Last previous edition approved in 2005 as E1545 05. DOI:10.1520/E1545-11.2For referenced ASTM standards,
15、 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
16、York, NY 10036, http:/www.ansi.org.4Available from International Electrotechnical Commission (IEC), 3 rue deVaremb, Case postale 131, CH-1211, Geneva 20, Switzerland, http:/www.iec.ch.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5
17、.3 This test method is useful for research and development,quality control, and specification acceptance.6. Apparatus6.1 Thermomechanical Analyzer (TMA)The essential in-strumentation required to provide the minimum thermome-chanical analytical capability for this test method includes thefollowing:6.
18、1.1 A rigid specimen holder, composed of inert lowexpansivity material #1mm1C1, to center the specimenin the furnace and to fix the specimen to mechanical ground.6.1.2 A rigid circular expansion probe, 2 to 6 mm indiameter, composed of inert low expansivity material #1mm1C1, that contacts the specim
19、en with an applied com-pressive force.6.1.3 A linear sensing element with a nominal range of2-mm capable of measuring the displacement in length of thespecimen readable to within 650 nm.6.1.4 A weight or force transducer to generate a constantforce of 0 to 50 mN that is applied through the rigidcomp
20、ression probe to the specimen.6.1.5 A furnace capable of providing uniform controlledheating (cooling) of a specimen to a constant temperature or ata constant rate over the temperature range of 100 to 600 C.6.1.6 A temperature controller capable of executing a spe-cific temperature program by operat
21、ing the furnace betweenselected temperature limits at a rate of temperature change of5 6 0.5 C/minute.6.1.7 A temperature sensor that can be attached to, incontact with, or reproducibly placed in close proximity to thespecimen to provide an indication of the specimen/furnacetemperature to 60.1 C.6.1
22、.8 A means of sustaining an environment around thespecimen of a dry inert purge gas of 45 to 55 mL/minute.NOTE 1Typically, 99.9+ % pure nitrogen, argon or helium is used.Unless effects of moisture are to be studied, dry purge gas is recommendedand is essential for operation at subambient temperature
23、s.6.1.9 A data collection device, to provide a means ofacquiring, storing, and displaying measured or calculatedsignals, or both. The minimum output signals required forthermomechanical analysis are change in linear dimension,temperature and time.6.2 Micrometer or other measuring device to determine
24、specimen dimensions of up to 8 mm to within 6 of 10 m.7. Hazards7.1 This test method may be used for amorphous andsemicrystalline materials having a glass transition that is at orbelow room temperature providing care is taken to avoidcontacting the specimen with a loaded probe prior to coolingthe sp
25、ecimen below its glass transition. Applying a loadedprobe to a specimen that is above its glass transition may causepartial penetration by the probe which can lead to probesticking upon cooling below the glass transition.This conditionhas been known to yield erroneous results during the heatingcycle
26、.7.2 With some materials a transient may be observedbetween the pre-transition slope and the final slope (Run 1 ofFig. 1). This may occur due to settling, residual stresses withinthe specimen, or alteration of the specimen morphology. Referto Note 5 for directions when this is encountered.7.3 Specim
27、ens of thickness less than 0.2 mm may be verydifficult to handle. Thin films (50 to 200 m) on a substratemay be considered for this test method providing the substrateis mechanically stable in the temperature region of the filmglass transition.7.4 For specimens of thickness greater than 5 mm, temper
28、a-ture nonuniformities of sufficient extent can develop within thespecimen as to yield erroneously high values of the glasstransition temperature using this test method.FIG. 1 Glass Transition Temperature from Expansion ModeE1545 1128. Sampling8.1 Analyze samples as received or after pretreatment. I
29、fsome treatment is applied to a specimen prior to analysis, notethis treatment and any resulting change in mass in the report.9. Calibration9.1 Perform calibration in accordance with Test MethodE1363.10. Procedure10.1 Calibrate the thermomechanical analyzer in accor-dance with Test Method E1363.10.2
30、 Place a preweighed specimen of 0.5 to 3-mm thicknesson the specimen holder in line with the probe. BE SURE THEPOSITIONING OF THE TEMPERATURE SENSOR IS UN-CHANGED FROM THAT USED IN THE CALIBRATIONPROCEDURE.NOTE 2Refer to Section 7 if thicknesses outside of this range are tobe used.10.3 Move the furn
31、ace to enclose the specimen and holder.Start the dry inert gas purge before cooling or heating thespecimen.NOTE 3If measurements are to be made at or below ambienttemperature, cool the specimen and furnace to a temperature equivalent toat least 3 min of heating below the first temperature of interes
32、t to ensurestable heater control, for example, 15 C for 5 C/min. The refrigerantused for cooling should not come in direct contact with the specimen.10.4 Procedure AExpansion ModeThe transition tem-perature derived from this procedure is considered the glasstransition temperature.10.4.1 Lower the pr
33、obe (4 to 6-mm diameter) into contactwith the specimen and apply a force of 0 to 5 mN (or asrecommended by the instrument manufacturer) to the probe.10.4.2 Heat the specimen at a constant heating rate of 5C/min over the desired temperature range.NOTE 4Other forces and heating rates may be used if ap
34、plied both inthe calibration and throughout the testing. The conditions used shall benoted in the report.10.4.3 Note the occurrence of an abrupt positive change inthe slope of the linear thermal expansion that indicates atransition of the material from one state to another (Run 2 ofFig. 1).NOTE 5If
35、a sudden irreversible deflection is observed as in Run 1 ofFig. 1, stop the heating program 20 C above this temperature, remove anyapplied force from the probe, raise the probe from the specimen, and coolthe specimen and furnace to the original start temperature. Conduct asecond thermal cycle on the
36、 specimen beginning with 10.4.1.10.4.4 Upon reaching the limit temperature of the heatingprogram, remove any applied force from the probe, raise theprobe from the specimen, and restore the furnace and specimenholder to room temperature.10.5 Procedure BPenetration ModeThe transition tem-perature deri
37、ved from this procedure is referred to as thesoftening point, Ts. For most materials Tsis close to the Tgasmeasured in the expansion mode or as measured by differentialscanning calorimetry. It is a common practice in many polymerlaboratories to report Tsfor Tg. The value of Tsmay be affectedby the a
38、pplied force and the probe contact area. Hence, thosevalues should also be reported when using this procedure.10.5.1 Lower the probe (2 to 4-mm diameter) into contactwith the specimen and apply a force of 20 to 50 mN to theprobe.10.5.2 Heat the specimen at a constant heating rate of 5C/min over the
39、desired temperature range.NOTE 6Other forces and heating rates may be used if applied both inthe calibration and throughout the testing. The conditions used shall benoted in the report.10.5.3 Note the occurrence of an abrupt negative change inthe slope of the thermal curve which indicates a transiti
40、on ofthe material from one state to another (Run 2 of Fig. 2).FIG. 2 Softening Point from Penetration ModeE1545 113NOTE 7If a sudden irreversible deflection is observed as in Run 1 ofFig. 2, stop the heating program 20 C above this temperature, remove theapplied force from the probe, raise the probe
41、 from the specimen, and coolthe specimen and furnace to the original start temperature. Conduct asecond thermal cycle on the specimen beginning with 10.5.1.10.5.4 Upon reaching the limit temperature of the heatingprogram, remove the applied force from the probe, raise theprobe from the specimen, and
42、 restore the furnace and specimenholder to room temperature.10.6 Reweigh the specimen after the measurement andreport any mass change along with any thermal pretreatmentincluding any previous thermal cycles using either ProcedureAor B.NOTE 8Weighing of the specimen is required to ensure whetherchang
43、es such as loss of solvent or plasticizer that may have changed theobserved glass transition temperature have occurred.11. Calculation11.1 Derive the glass transition temperature from ProcedureA as follows using graphics or software:11.1.1 Construct a tangent to the low-temperature thermal-expansion
44、 curve.11.1.2 Construct a tangent to the thermal-expansion curvebeyond the transition.11.1.3 The temperature at which these tangents intersect isthe observed glass transition temperature, Tg.11.2 Derive the softening point from Procedure B as followsusing graphics or software:11.2.1 Construct a tang
45、ent to the low temperature portion ofthe thermal curve.11.2.2 Construct a tangent to the steepest portion of thepenetration slope beyond the transition.11.2.3 The temperature at which these tangents intersect isthe observed softening point, Ts.11.3 Determine the corrected Tgor Tsby applying anytempe
46、rature correction determined from the instrument tem-perature calibration to the observed values of Tgor Ts.12. Report12.1 Report the following information:12.1.1 Complete identification and description of the mate-rial tested including dimensions and any pretreatment,12.1.2 Description of the instr
47、ument used for the testincluding manufacturer, model number, probe size, probeshape, and applied force,12.1.3 Description of the temperature calibration procedure,12.1.4 Purge gas, flow rate, and cooling medium if used,12.1.5 The corrected glass transition temperature, Tg,orthecorrected softening po
48、int, Ts,12.1.6 The thermomechanical measurement curves, and12.1.7 Any change in mass during the test.12.1.8 The specific dated version of this test method used.13. Precision and Bias513.1 An interlaboratory study of the measurement of theglass transition temperature of an epoxy composite was con-duc
49、ted in 1993. Following temperature calibration using phe-nyl ether and indium melting temperatures, each of eightlaboratories tested four specimens. Instruments from fourmanufacturers were used. The results were treated by PracticeE691.13.2 PrecisionTwo values, each the mean of duplicatedetermination, should be considered suspect if they differ bymore than the 95 % confidence limits defined below:13.2.1 Repeatability (within laboratory) = r = 3.6 C.13.2.2 Reproducibility (between laboratory) = R = 11.4 C.13.2.3 These limits are calculat
