1、Designation: E2602 09 (Reapproved 2015)Standard Test Methods forthe Assignment of the Glass Transition Temperature byModulated Temperature Differential Scanning Calorimetry1This standard is issued under the fixed designation E2602; the number immediately following the designation indicates the year
2、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 These test methods describe the assignment of the glasstr
3、ansition temperature of materials using modulated tempera-ture differential scanning calorimetry (MTDSC) over thetemperature range from 120 to +600C. The temperaturerange may be extended depending upon the instrumentationused.1.2 The values stated in SI units are to be regarded asstandard. No other
4、units of measurement are included in thisstandard.1.3 There are no ISO equivalents to this standard.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 heal
5、th practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and Rhe-ologyE967 Test Method for Temperature Calibration of Differen-tial Scanning Calorimeters and Differential Thermal Ana-
6、lyzersE968 Practice for Heat Flow Calibration of DifferentialScanning CalorimetersE1142 Terminology Relating to Thermophysical PropertiesE1356 Test Method for Assignment of the Glass TransitionTemperatures by Differential Scanning CalorimetryE1545 Test Method for Assignment of the Glass TransitionTe
7、mperature by Thermomechanical AnalysisE1640 Test Method for Assignment of the Glass TransitionTemperature By Dynamic Mechanical Analysis3. Terminology3.1 DefinitionsSpecific technical terms found in these testmethods are defined in Terminologies E473 and E1142 includ-ing differential scanning calori
8、metry, glass transition, glasstransition temperature, specific heat capacity, and thermalcurve.3.2 Definitions of Terms Specific to This Standard:3.2.1 extrapolated end temperature (Te), nthe point ofintersection of the tangent drawn at the point of greatest slope(that is, the inflection point) in t
9、he transition region with theextrapolated baseline following the transition.3.2.2 extrapolated onset temperature (Tf), nthe point ofintersection of the tangent drawn at the point of greatest slope(that is, the inflection point) in the transition region with theextrapolated baseline prior to the tran
10、sition.3.2.3 midpoint temperature (Tm), nthe point on the ther-mal curve corresponding to the average of the extrapolatedonset 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 he
11、at flow resulting froman applied modulated temperature program.3.2.6 modulated temperature differential scanning calorim-etry (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 specimeno
12、ver a traditional isothermal or temperature ramp program.Results from the experiment include reversing and nonrevers-ing heat 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 an
13、d not to the temperature rate ofchange.3.2.8 reversing heat flow, nthe portion of the total heatflow that responds to the temperature rate of change.3.2.9 total heat flow, nthe value of the modulated heatflow averaged over one modulation period or impulse.1These test methods are under the jurisdicti
14、on of ASTM Committee E37 onThermal Measurements and is the direct responsibility of Subcommittee E37.01 onCalorimetry and Mass Loss.Current edition approved May 1, 2015. Published May 2015. Originallyapproved in 2009. Last previous edition approved in 2009 as E2602 09. DOI:10.1520/E2602-09R15.2For r
15、eferenced 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, W
16、est Conshohocken, PA 19428-2959. United States13.2.9.1 DiscussionThe total heat flow is equivalent to theheat flow signal of conventional differential scanning calorim-etry.3.2.9.2 DiscussionThe total heat flow is equal to the sumof the reversing and nonreversing heat flows.4. Summary of Test Method
17、4.1 The determination of the glass transition by differentialscanning calorimetry using Test Method E1356 is difficultwhen kinetic events such as the cure exotherm of a thermosetresin occur at or near the glass transition. In MTDSC, the totalheat flow signal is separated into reversing and nonrevers
18、ingcomponents. The heat capacity change that indicates the glasstransition appears in the reversing heat flow signal, whilekinetic events (for example, curing, enthalpy of recovery, etc.)appear in the nonreversing heat flow signal. The separation ofthese two signals permits the determination of the
19、enthalpy ofreaction and the assignment of the glass transition in a singleexperiment.4.1.1 This MTDSC method involves the continuous moni-toring of the reversing and nonreversing heat flow into or outof a test specimen as it is heated at a controlled rate through theglass transition region.5. Signif
20、icance 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 kinetic events suchas enthalpic recovery, chemical reaction or crystallization attemperatures near the glass transiti
21、on. 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 sigmoidal or step change in specific heatcapacity.5.3 MTDSC provides a test method for the separation of thehe
22、at 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 These test methods are useful in research anddevelopment, quality assurance and control and specificationacceptance.5.5 Other metho
23、ds for assigning the glass transition tem-perature include differential scanning calorimetry (Test MethodE1356), thermomechanical analysis (Test Method E1545) anddynamic mechanical analysis (Test Method E1640).6. Apparatus6.1 The instrumentation required to provide the capabilityfor these test metho
24、ds includes a MTDSC composed of:6.1.1 A differential scanning calorimeter (DSC) test cham-ber of (1)afurnace or furnaces to provide uniform controlledheating or cooling of a specimen and reference to a constanttemperature or at a constant rate within the range from 120 to+600C, (2) a temperature sen
25、sor to provide an indication ofthe specimen temperature readable to 60.01C, (3) a differen-tial sensor to detect a heat flow difference between specimenand reference equivalent to 1 W and (4) a means of sustaininga test chamber environment of inert nitrogen (or other lowconductivity) purge gas at a
26、rate of 20 to 60 mL/min constantto within 610 %.NOTE 1The temperature range of interest depends upon the tempera-ture of the glass transition. The apparatus need only address the tempera-ture region from 50C below to 50C above the anticipated glass transitiontemperature.6.1.2 A temperature controlle
27、r, capable of executing aspecific temperature program by (1) operating the furnacebetween selected temperature limits at a rate of temperaturechange of 7 6 0.1C/min, (2) holding at an isothermaltemperature within the temperature range of 120 to +600Cwithin 60.1C, and (3) for Test MethodA, varying te
28、mperaturesinusoidally with an amplitude of 60.9 to 1.1C and a periodof 50 to 71 s (frequency of 14 to 20 mHz) or applying a60.5C 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
29、flow signals into the required continuousoutput forms of reversing and nonreversing heat flow andaverage test temperature to the 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 minimu
30、m output signals required for MTDSCare heat flow, reversing heat flow, nonreversing heat flow,elapsed time and average specimen temperature signals.6.2 A coolant system to provide cooling at rates of at least2C/min.6.3 Inert nitrogen or other low conductivity purge gasflowing at a rate of 20 to 60 m
31、L/min constant to within 610 %.NOTE 2Helium, a commonly used purge gas with high thermalconductivity, may result in reduced temperature 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 container
32、s, or both to 60.01 mg.6.5 A Sapphire disk calibration material,10to30mgforheat capacity calibration.6.6 Indium metal of 99.99 % purity for temperature andenthalpy calibration.6.7 Containers (pans, crucibles, etc.) that are inert to thespecimen and are of suitable structural shape and integrity toco
33、ntain the specimen in accordance with the specific require-ments of these test methods.6.8 A means, tool or device to close, encapsulate or seal thecontainer of choice.7. Calibration and Standardization7.1 Calibrate the temperature signal from the MTDSCapparatus in accordance with Practice E967 usin
34、g an indiumreference material and a heating rate of 5C/min (see Note 3and Note 5).7.2 Calibrate the total heat flow signal from the MTDSCapparatus in accordance with Practice E968 using an indiumreference material.E2602 09 (2015)27.3 Calibrate the apparatus for modulated temperature de-rived signals
35、 (such as reversing heat flow, nonreversing heatflow, etc.) with the instructions provided by the manufactureras described in the operations manual using the sapphirecalibration material (6.4) and 5C/min heating rate, 61Camplitude and 60 s period (16.5 mHz frequency) or 61.0Ctemperature impulse with
36、 15 to 30 s duration.NOTE 3The calibration shall be performed using the same heatingrate, and temperature modulation conditions to be used for the testspecimen.8. ProcedureTEST METHOD ASINUSOIDAL TEMPERATURE8.1 Into a tared container weigh to within 60.01 mg, 5 to20 mg of the test specimen. Seal a l
37、id on the sample container.8.2 Beginning at a temperature at least 50C below theanticipated glass transition temperature, initiate the tempera-ture modulation at an amplitude of 61C and a period of 60 s.Record the total, reversing and nonreversing heat flow signalswith a data collection rate of 1 s/
38、point or faster.NOTE 4Other temperature ranges, amplitudes and periods may beused but shall be reported.8.3 Initiate an underlying heating rate of 5C/min to an endtemperature approximately 50C higher than the end of theglass transition.NOTE 5Other heating rates may be used but shall be reported.NOTE
39、 6Other temperature ranges, amplitudes and periods may beused but shall be reported.8.4 Prepare a plot of reversing heat flow 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 sign
40、al such as that shown inFig. 1.8.5 Construct a tangent to the baseline before the glasstransition, extrapolating it to higher temperatures. Construct atangent to the baseline after the glass transition, extrapolatingit to lower temperatures. Construct a tangent at the point ofmaximum slope (that is,
41、 the inflection point) in the midst of theglass transition until it intersects with the two baseline con-structions. The intersection 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
42、the midpoint between Tf and Te, that is, Tm=(Tf+Te)/2.8.7 Report the glass transition temperature (Tg) to be that ofthe midpoint temperature (Tm).NOTE 7Other temperatures between Tf and Te may be used but shallbe reported.TEST METHOD BSTEP TEMPERATURE8.8 Into a tared container weigh 5 to 20 mg of th
43、e testspecimen to within 60.01 mg. Seal a lid on the samplecontainer.8.9 Beginning at a temperature at least 50C below theanticipated glass transition temperature, start a program oftemperature increments of 1C with a heating rate of 5C/min(see Note 8) and isothermal holding for 1 minute with theadv
44、ancement condition of stability5Wover6stoatemperature that is approximately 50C above the anticipatedglass transition temperature.NOTE 8Other temperature increments, heating rates, isothermal hold-ing periods and advancement condition may be used but shall be reported.NOTE 9The temperature increment
45、s shall be sufficiently small that atleast five full steps occur across the glass transition8.10 Prepare a plot of specific heat capacity on the ordinate(Y-axis) versus average sample temperature on the abscissaFIG. 1 Reversing Heat Flow and Specific Heat Capacity in the Region of the Glass Transiti
46、onE2602 09 (2015)3(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 higher temperatures. Construct atangent to the baseline after the glas
47、s transition, extrapolatingit to lower temperatures. Construct a tangent at the point ofmaximum slope (that is, the inflection point) in the midst of theglass transition until it intersects with the two baseline con-structions. The intersections points with the baseline beforeand after the glass tra
48、nsition are identified as Tf and Te,respectively.8.12 The midpoint transition temperature (Tm) is deter-mined as the midpoint between Tf and Te, that is, Tm = (Tf +Te)/2.8.13 Report the glass transition temperature (Tg) to be thatof the midpoint temperature (Tm).NOTE 10Other temperatures between Tf
49、and Te may be used but shallbe reported.TEST METHOD CTEMPERATURE PULSE8.14 Into a tared container weigh to within 60.01 mg, 5 to20 mg of the test specimen. Seal a lid on the sample container.8.15 Beginning at a temperature at least 50C below theanticipated glass transition temperature, initiate an pulse of60.5C 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 11 Other temperature ranges, pulse amplitudes and durationsmay be used bu
