1、Designation: E 2602 09Standard Test Method forthe Assignment of the Glass Transition Temperature byModulated Temperature Differential Scanning Calorimetry1This standard is issued under the fixed designation E 2602; the number immediately following the designation indicates the year oforiginal adopti
2、on 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 This test method describes the assignment of the glasstransition temperatu
3、re of materials using modulated tempera-ture differential scanning calorimetry (MTDSC) over thetemperature range from 120 to + 600 C. The temperaturerange may be extended depending upon the instrumentationused.1.2 SI units are the standard.1.3 There are no ISO equivalents to this standard.1.4 This s
4、tandard 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.
5、1 ASTM Standards:2E 473 Terminology Relating to Thermal Analysis and Rhe-ologyE 967 Test Method for Temperature Calibration of Differ-ential Scanning Calorimeters and Differential ThermalAnalyzersE 968 Practice for Heat Flow Calibration of DifferentialScanning CalorimetersE 1142 Terminology Relating
6、 to Thermophysical PropertiesE 1356 Test Method for Assignment of the Glass TransitionTemperatures by Differential Scanning CalorimetryE 1545 Test Method for Assignment of the Glass TransitionTemperature by Thermomechanical AnalysisE 1640 Test Method for Assignment of the Glass TransitionTemperature
7、 By Dynamic Mechanical Analysis3. Terminology3.1 Specific technical terms found in this test method aredefined in Terminologies E 473 and E 1142 including differ-ential scanning calorimetry, glass transition, glass transitiontemperature, specific heat capacity and thermal curve.3.2 Definitions of Te
8、rms Specific to This Standard:3.2.1 extrapolated end temperature (Te), nthe point ofintersection of the tangent drawn at the point of greatest slope(i.e., the inflection point) in the transition region with theextrapolated baseline following the transition.3.2.2 extrapolated onset temperature (Tf),
9、nthe point ofintersection of the tangent drawn at the point of greatest slope(i.e., the inflection point) in the transition region with theextrapolated baseline prior to the transition.3.2.3 midpoint temperature (Tm), nthe point on the ther-mal curve corresponding to the average of the extrapolatedo
10、nset and extrapolated end temperatures.3.2.4 modulated , na prefix indicating that a parameterchanges in a periodic manner during the experiment.3.2.5 modulated heat flow, nthe heat flow resulting froman applied modulated temperature program3.2.6 modulated temperature differential scanning calorim-e
11、try (MTDSC), na method of differential scanning calorim-etry (DSC) that varies the temperature sinusoidally or with aperiodic step-and-hold or pulse program to the test specimenover a traditional isothermal or temperature ramp program.Results from the experiment include reversing and nonrevers-ing h
12、eat flow and specimen temperature.3.2.7 nonreversing heat flow, nthe kinetic component ofthe total heat flow. That is, the portion of the heat flow thatresponds to temperature and not to the temperature rate ofchange.3.2.8 reversing heat flow , nthe portion of the total heatflow that responds to the
13、 temperature rate of change.3.2.9 total heat flow, n The value of the modulated heatflow averaged over one modulation period or impulseNOTE 1The total heat flow is equivalent to the heat flow signal ofconventional differential scanning calorimetry.NOTE 2The total heat flow is equal to the sum of the
14、 reversing andnonreversing heat flows.4. Summary of Test Method4.1 The determination of the glass transition by differentialscanning calorimetry using standard Test Method E 1356 isdifficult when kinetic events such as the cure exotherm of athermoset resin occur at or near the glass transition. In1T
15、his test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 onCalorimetry and Mass Loss.Current edition approved April 15, 2009. Published June 2009.2For referenced ASTM standards, visit the ASTM website, www.astm.org,
16、 orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.modulated tempe
17、rature differential scanning calorimetry(MTDSC) the total heat flow signal is separated into reversingand nonreversing components. The heat capacity change thatindicates the glass transition appears in the reversing heat flowsignal, while kinetic events (e.g., curing, enthalpy of recovery,etc.) appe
18、ar in the nonreversing heat flow signal. The separa-tion of these two signals permits the determination of theenthalpy of reaction and the assignment of the glass transitionin a single experiment.4.1.1 This MTDSC method involves the continuous moni-toring of the reversing and nonreversing heat flow
19、into or outof a test specimen as it is heated at a controlled rate through theglass transition region.5. Significance and Use5.1 Materials undergo an increase in molecular mobility atthe glass transition seen as a sigmoidal step increase in the heatcapacity. This mobility increase may lead to kineti
20、c events suchas enthalpic recovery, chemical reaction or crystallization attemperatures near the glass transition. The heat flow associatedwith the kinetic events may interfere with the determination ofthe glass transition.5.2 The glass transition is observed in differential scanningcalorimetry as a
21、 sigmoidal or step change in specific heatcapacity.5.3 MTDSC provides a test method for the separation of theheat flow due to heat capacity and that associated with kineticevents making it possible to determine the glass transition inthe presence of interfering kinetic event.5.4 This test method is
22、useful in research and development,quality assurance and control and specification acceptance.5.5 Other methods for assigning the glass transition tem-perature include differential scanning calorimetry (Test MethodE 1356), thermomechanical analysis (Test Method E 1545) anddynamic mechanical analysis
23、 (Test Method E 1640)6. Apparatus6.1 The instrumentation required to provide the capabilityfor this test method includes a Modulated Temperature Differ-ential Scanning Calorimeter composed of:6.1.1 A differential scanning calorimeter (DSC) test cham-ber of (1) a furnace or furnaces to provide unifor
24、m controlledheating or cooling of a specimen and reference to a constanttemperature or at a constant rate within the range from 120 to+ 600 C, (2) a temperature sensor to provide an indication ofthe specimen temperature readable to 6 0.01 C, (3) adifferential sensor to detect a heat flow difference
25、betweenspecimen and reference equivalent to 1 W and (4) a means ofsustaining a test chamber environment of inert nitrogen (orother low conductivity) purge gas at a rate of 20 to 60 mL/minconstant to within 610 %.NOTE 3The temperature range of interest depends upon the tempera-ture of the glass trans
26、ition. The apparatus need only address the tempera-ture region from 50 C below to 50 C above the anticipated glasstransition temperature.6.1.2 A temperature controller, capable of executing aspecific temperature program by (1) operating the furnacebetween selected temperature limits at a rate of tem
27、peraturechange of 7 6 0.1 C/min, (2) holding at an isothermaltemperature within the temperature range of -120 to + 600 Cwithin 6 0.1 C, and (3) for method A, varying temperaturesinusoidally with an amplitude of 6 0.9 to 1.1 C and a periodof 50 to 71 s (frequency of 14 to 20 mHz) or applying a 60.5 C
28、 pulse at intervals between 15 and 30 s.6.1.3 A calculating device, capable of transforming theexperimentally determined modulated temperature and modu-lated specimen heat flow signals into the required continuousoutput forms of reversing and nonreversing heat flow andaverage test temperature to the
29、 required accuracy and preci-sion.6.1.4 A data collection device, to provide a means ofacquiring, storing and displaying measured or calculated sig-nals or both. The minimum output signals required for MTDSCare heat flow, reversing heat flow, nonreversing heat flow,elapsed time and average specimen
30、temperature signals.6.2 A coolant system to provide cooling at rates of at least 2C/min.6.3 Inert nitrogen or other low conductivity purge gasflowing at a rate of 20 to 60 mL/min constant to within 6 10%.NOTE 4Helium, a commonly used purge gas with high thermalconductivity, may result in reduced tem
31、perature range, precision andaccuracy. Follow the manufacturers recommendation when using helium.6.4 A balance with a range of at least 200 mg to weighspecimens or containers, or both to 6 0.01 mg.6.5 A Sapphire disk calibration material,10to30mgforheat capacity calibration.6.6 Indium metal of 99.99
32、 % purity for temperature andenthalpy calibration.6.7 Containers (pans, crucibles, etc.) that are inert to thespecimen and are of suitable structural shape and integrity tocontain the specimen in accordance with the specific require-ments of this test method.6.8 A means, tool or device to close, enc
33、apsulate or seal thecontainer of choice.7. Calibration and Standardization7.1 Calibrate the temperature signal from the MTDSCapparatus in accordance with Practice E 967 using an indiumreference material and a heating rate of 5 C/min (see notes 5and 7).7.2 Calibrate the total heat flow signal from th
34、e MTDSCapparatus in accordance with Practice E 968 using an indiumreference material.7.3 Calibrate the apparatus for modulated temperature de-rived signals (such as reversing heat flow, nonreversing heatflow, etc.) with the instructions provided by the manufactureras described in the operations manu
35、al using the sapphirecalibration material (section 6.4) and 5 C/min heating rate, 61 C amplitude and 60 s period (16.5 mHz frequency) or 61.0C temperature impulse with 15 to 30 s duration.NOTE 5The calibration shall be performed using the same heatingrate, and temperature modulation conditions to be
36、 used for the testspecimen.E26020928. ProcedureMethod A Sinusoidal Temperature8.1 Into a tared container weigh to within 6 0.01 mg, 5 to20 mg of the test specimen. Seal a lid on the sample container.8.2 Beginning at a temperature at least 50 C below theanticipated glass transition temperature, initi
37、ate the tempera-ture modulation at an amplitude of 6 1 C and a period of 60s. Record the total, reversing and nonreversing heat flowsignals with a data collection rate of 1 s/point or faster.NOTE 6Other temperature ranges, amplitudes and periods may beused but shall be reported.8.3 Initiate an under
38、lying heating rate of 5 C/min to an endtemperature approximately 50 C higher than the end of theglass transition.NOTE 7Other heating rates may be used but shall be reported.NOTE 8Other temperature ranges, amplitudes and periods may beused but shall be reported.8.4 Prepare a plot of reversing heat fl
39、ow on the ordinate(Y-axis) versus average sample temperature on the abscissa(X-axis). The glass transition is indicated by a sigmoidal stepchange in the reversing heat flow signal such as that shown inFig. 1.8.5 Construct a tangent to the baseline before the glasstransition, extrapolating it to high
40、er temperatures. Construct atangent to the baseline after the glass transition, extrapolatingit to lower temperatures. Construct a tangent at the point ofmaximum slope (i.e., the inflection point) in the midst of theglass transition until it intersects with the two baseline con-structions. The inter
41、section points with the baseline before andafter the glass transition are identified as Tf and Te, respec-tively.8.6 The midpoint transition temperature (Tm) is determinedas the midpoint between Tf and Te, that is, Tm=(Tf+Te)/2.8.7 Report the glass transition temperature (Tg) to be that ofthe midpoi
42、nt temperature (Tm).NOTE 9Other temperatures between Tf and Te may be used but shallbe reported.Method B Step Temperature8.8 Into a tared container weigh 5 to 20 mg of the testspecimen to within 6 0.01 mg. Seal a lid on the samplecontainer.8.9 Beginning at a temperature at least 50 C below theantici
43、pated glass transition temperature, start a program oftemperature increments of 1 C with a heating rate of 5 C/min(see note 10) and isothermal holding for 1 minute with theadvancement condition of stability5Wover6stoatemperature that is approximately 50 C above the anticipatedglass transition temper
44、ature.NOTE 10Other temperature increments, heating rates, isothermalholding periods and advancement condition may be used but shall bereported.NOTE 11The temperature increments shall be sufficiently small that atleast 5 full steps occur across the glass transition8.10 Prepare a plot of specific heat
45、 capacity on the ordinate(Y-axis) versus average sample temperature on the abscissa(X-axis). The glass transition is indicated by a sigmoidal stepchange in the specific heat capacity signal as shown in Fig. 1.8.11 Construct a tangent to the baseline before the glasstransition, extrapolating to highe
46、r temperatures. Construct atangent to the baseline after the glass transition, extrapolatingit to lower temperatures. Construct a tangent at the point ofmaximum slope (i.e., the inflection point) in the midst of theglass transition until it intersects with the two baseline con-structions. The inters
47、ections points with the baseline beforeand after the glass transition are identified as Tf and Te,respectively.FIG. 1 Reversing Heat Flow and Specific Heat Capacity in the Region of the Glass TransitionE26020938.12 The midpoint transition temperature (Tm) is deter-mined as the midpoint between Tf an
48、d Te, that is, Tm = (Tf +Te)/2.8.13 Report the glass transition temperature (Tg) to be thatof the midpoint temperature (Tm).NOTE 12Other temperatures between Tf and Te may be used but shallbe reported.Method C Temperature Pulse8.14 Into a tared container weigh to within 6 0.01 mg, 5 to20 mg of the t
49、est specimen. Seal a lid on the sample container.8.15 Beginning at a temperature at least 50 C below theanticipated glass transition temperature, initiate an pulse of 60.5 C and a duration of 15 to 30 s. Record the total, reversingand nonreversing heat flow signals with a data collection rateof 1 s/point or faster.NOTE 13 Other temperature ranges, pulse amplitudes and durationsmay be used but shall be reported.8.16 Initiate an underlying heating rate of 5 C/min to anend temperature approximately 50 C higher than the end ofthe
