1、Designation: E 1545 05Standard Test Method forAssignment of the Glass Transition Temperature byThermomechanical Analysis1This standard is issued under the fixed designation E 1545; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、on heatingusing thermomechanical measurements under prescribed ex-perimental 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 temp
4、erature range is from 100to 600C. This temperature range may be extended dependingupon the instrumentation used.1.4 SI units are the standard.1.5 This test method is related to ISO 11359-2. ISO 11359-2additionally covers the determination of coefficient of linearthermal expansion not covered by this
5、 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 theresponsibility of the user of this standard to establish appro-priate safety and health practices an
6、d 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:E 473 Terminology Relating to Thermal Analysis and Rhe-ologyE 691 Practice for Conducting an Interlaboratory Study toDetermine th
7、e Precision of a Test MethodE 1142 Terminology Relating to Thermophysical PropertiesE 1363 Test Method for Temperature Calibration of Ther-momechanical Analyzers2.2 Other Standard:ISO 11359-2 PlasticsThermomechanicalAnalysis (TMA) Part 2: Determination of Coefficient of Linear ThermalExpansion and G
8、lass Transition Temperature2IEC 61006 Methods of Test for the Determination of theGlass Transition Temperature of Electrical Insulating Ma-terials33. Terminology3.1 DefinitionsThe following terms are applicable to thistest method and can be found in Terminologies E 473 andE 1142: thermomechanical an
9、alysis (TMA), thermomechanicalmeasurement, thermodilatometry, glass transition, glass tran-sition temperature, and linear thermal expansion.4. Summary of Test Method4.1 This test method uses thermomechanical analysis equip-ment (thermomechanical analyzer, dilatometer, or similar de-vice) to assign t
10、he 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 amorphous liquid isobserved as movement of the sensing probe in direct contactwith the speci
11、men 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 temperature.5. Significance and Use5.1 The glass transition is dependent on the thermal historyo
12、f 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, progress of chemical reactions,and mechanical and electrical behavior.5.2 Thermomechanic
13、al analysis provides a rapid means ofdetecting changes in hardness or linear expansion associatedwith the glass transition.1This test method is under the jurisdiction of ASTM Committee E-37 onThermal Measurements and is the direct responsibility of Subcommittee E37.01 onTest Methods and Recommended
14、Practices.Current edition approved Dec. 1, 2005. Published August 2006. Originallyapproved in 1993. Last previous edition approved in 2000 as E 1545 00.2Available from American National Standards Institute, 11 W. 42nd St., 13thFloor, New York, NY 10036.3Available from International Electrotechnical
15、Commission (IEC), 3 rue deVaremb, Case postale 131, CH-1211, Geneva 20, Switzerland.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3 This test method is useful for research and development,quality control, and specification accept
16、ance.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:6.1.1 A rigid specimen holder, composed of inert lowexpansivity material #1mm1C1, to center the specim
17、enin 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 specimen with an applied compres-sive force.6.1.3 A linear sensing element with a nominal range of2-mm cap
18、able of measuring the displacement in length of thespecimen readable to within 6 50 nm.6.1.4 A weight or force transducer to generate a constantforce of 0 to 50 mN that is applied through the rigidcompression probe to the specimen.6.1.5 A furnace capable of providing uniform controlledheating (cooli
19、ng) of a specimen to a constant temperature or ata constant rate over the temperature range of 100 to 600C.6.1.6 A temperature controller capable of executing a spe-cific temperature program by operating the furnace betweenselected temperature limits at a rate of temperature change of5 6 0.5C/minute
20、.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 6 0.1C.6.1.8 A means of sustaining an environment around thespecimen of a dry inert purge gas of 45 to 55 mL/mi
21、nute.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 temperatures.6.1.9 A recording device, capable of recording and display-ing any fraction of the specimen dimensi
22、on signal, includingsignal noise, on the Y-axis versus any fraction of the tempera-ture signal, including noise, on the X-axis.6.2 Micrometer or other measuring device to determinespecimen dimensions of up to 8 mm with a precision of 10 m.7. Hazards7.1 This test method may be used for amorphous ands
23、emicrystalline 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 specimen below its glass transition. Applying a loadedprobe to a specimen that is above its glass transition may caus
24、epartial 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.7.2 With some materials a transient may be observedbetween the pre-transition slope and the final slope (Run 1 ofF
25、ig. 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 Specimens of thickness less than 0.2 mm may be verydifficult to handle. Thin films (50 to 200 m) on a substratemay be con
26、sidered 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, tempera-ture nonuniformities of sufficient extent can develop within thespecimen as to yield erroneously high values of t
27、he glasstransition temperature using this test method.8. Sampling8.1 Analyze samples as received or after pretreatment. Ifsome 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 w
28、ith Test MethodE 1363.10. Procedure10.1 Calibrate the thermomechanical analyzer in accor-dance with Test Method E 1363.10.2 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
29、 IN THE CALIBRATIONPROCEDURE.NOTE 2Refer to Section 7 if thicknesses outside of this range are tobe used.10.3 Move the furnace 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, c
30、ool the specimen and furnace to a temperature equivalent toFIG. 1 Glass Transition Temperature from Expansion ModeE1545052at least 3 min of heating below the first temperature of interest to ensurestable heater control, for example, 15C for 5C/min. The refrigerant usedfor cooling should not come in
31、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 probe (4 to 6-mm diameter) into contactwith the specimen and apply a force of 0 to 5 mN (or asrecommended by the instr
32、ument manufacturer) to the probe.10.4.2 Heat the specimen at a constant heating rate of5C/min over the desired temperature range.NOTE 4Other forces and heating rates may be used if applied both inthe calibration and throughout the testing. The conditions used shall benoted in the report.10.4.3 Note
33、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 a sudden irreversible deflection is observed as in Run 1 ofFig. 1, stop the heating program 20C above this temperatur
34、e, 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 specimen beginning with 10.4.1.10.4.4 Upon reaching the limit temperature of the heatingprogram, remove any applied f
35、orce 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 derived from this procedure is referred to as thesoftening point, Ts. For most materials Tsis close to the Tgasmeasured in
36、 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 applied force and the probe contact area. Hence, thosevalues should also be reported when using this procedure.10.5.1 L
37、ower 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 of5C/min over the desired temperature range.NOTE 6Other forces and heating rates may be used if applied both inthe calibration and throug
38、hout 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 transition ofthe material from one state to another (Run 2 of Fig. 2).NOTE 7If a sudden irreversible deflection is observed as
39、in Run 1 ofFig. 2, stop the heating program 20C above this temperature, remove theapplied 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 specimen beginning with 10.5.1.10.5.4 Upon reach
40、ing the limit temperature of the heatingprogram, remove the applied force from the probe, raise theprobe from the specimen, and restore the furnace and specimenholder to room temperature.10.6 Reweigh the specimen after the measurement andreport any mass change along with any thermal pretreatmentincl
41、uding any previous thermal cycles using either ProcedureAor B.NOTE 8Weighing of the specimen is required to ensure whetherchanges such as loss of solvent or plasticizer that may have changed theobserved glass transition temperature have occurred.11. Calculation11.1 Derive the glass transition temper
42、ature from ProcedureA as follows using graphics or software:11.1.1 Construct a tangent to the low-temperature thermal-expansion 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 transitio
43、n temperature, Tg.11.2 Derive the softening point from Procedure B as followsusing graphics or software:11.2.1 Construct a tangent 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 temperatur
44、e at which these tangents intersect isthe observed softening point, Ts.11.3 Determine the corrected Tgor Tsby applying anytemperature 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 i
45、dentification and description of the mate-rial tested including dimensions and any pretreatment,12.1.2 Description of the instrument used for the testincluding manufacturer, model number, probe size, probeshape, and applied force,12.1.3 Description of the temperature calibration procedure,FIG. 2 Sof
46、tening Point from Penetration ModeE154505312.1.4 Purge gas, flow rate, and cooling medium if used,12.1.5 The corrected glass transition temperature, Tg,orthecorrected softening point, Ts,12.1.6 The thermomechanical measurement curves, and12.1.7 Any change in mass during the test.12.1.8 The specific
47、dated version of this test method used.13. Precision and Bias413.1 An interlaboratory study of the measurement of theglass transition temperature of an epoxy composite was con-ducted in 1993. Following temperature calibration using phe-nyl ether and indium melting temperatures, each of eightlaborato
48、ries tested four specimens. Instruments from fourmanufacturers were used. The results were treated by PracticeE 691.13.2 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
49、 (within laboratory) = r = 3.6C.13.2.2 Reproducibility (between laboratory) = R = 11.4C.13.2.3 These limits are calculated from the respective stan-dard deviations and are related by the factor 2.8.13.2.4 Repeatability standard deviation = Sr= 1.3C.13.2.5 Reproducibility standard deviation = SR= 4.0C.13.3 Bias:13.3.1 The mean glass transition (Tg) of the epoxy compos-ite was determined to be 121.2 6 3.9C with 21 df.13.3.2 The glass transition temperature (Tg) of the epoxycomposite used in this study was also determined by dynamicmechanical
