1、Designation: E2716 09 (Reapproved 2014)Standard Test Method forDetermining Specific Heat Capacity by SinusoidalModulated Temperature Differential Scanning Calorimetry1This standard is issued under the fixed designation E2716; the number immediately following the designation indicates the year oforig
2、inal 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 This test method describes the determination of specificheat ca
3、pacity by sinusoidal modulated temperature differentialscanning calorimetry. For the determination of specific heatcapacity by a step-isothermal or multiple step-isothermaltemperature program, the reader is referred to Test MethodE1269.1.2 This test method is generally applicable to thermallystable
4、solids and liquids.1.3 The normal operating range of the test is from 100 to600C. The temperature range may be extended dependingupon the instrumentation and specimen holders used.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstand
5、ard.1.5 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 and determine the applica-bility of regulatory limitations prior to use.2. Referenc
6、ed 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-lyzersE968 Practice for Heat Flow Calibration of DifferentialScanning CalorimetersE1142 Terminol
7、ogy Relating to Thermophysical PropertiesE1269 Test Method for Determining Specific Heat Capacityby Differential Scanning Calorimetry3. Terminology3.1 DefinitionsSpecific technical terms found in this testmethod are defined in Terminologies E473 and E1142 includ-ing modulated temperature, isothermal
8、, differential scanningcalorimetry, frequency, heat capacity and specific heat capacity.3.2 Definitions of Terms Specific to This Standard:3.2.1 modulated temperature differential scanning calorim-etry (MTDSC), na version of differential scanning calorim-etry that provides a sinusoidally varying tem
9、perature programto the test specimen in addition to the traditional temperatureramp program.3.2.2 quasi-isothermal modulated temperature differentialscanning calorimetry, na variation of modulated temperaturedifferential scanning calorimetry in which a sinusoidally vary-ing temperature program is ap
10、plied to a test specimen aroundan underlying isothermal temperature4. Summary of Test Method4.1 The specific heat capacity of a test specimen may bedetermined using the modulated temperature approach inwhich an oscillatory or periodically repeating temperatureprogram is imposed upon a test specimen
11、producing anoscillatory (periodic) heat flow into or out of the specimen.4.1.1 Test Method A consists of heating the test specimen ina controlled atmosphere through the temperature region ofinterest, using temperature modulation conditions that areappropriate for the measurement.4.1.2 Test Method B
12、consists of equilibrating and holdingthe test specimen at an isothermal temperature in a controlledatmosphere and then applying appropriate temperature modu-lation conditions for the measurement. This procedure can berepeated using as many isothermal temperature holds as aredesired.4.2 The accuracy
13、of the heat capacity thus obtained dependsupon the experimental conditions. For example, when a thintest specimen encapsulated in a specimen pan of high thermalconductivity is treated with temperature oscillations of longperiod (low frequency), the test specimen achieves a uniform1This test method i
14、s under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on Calo-rimetry and Mass Loss.Current edition approved March 15, 2014. Published April 2014. Originallyapproved in 2009. Last previous edition approved in 2009 as E2716 09. DO
15、I:10.1520/E2716-09R14.2For 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 Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr
16、Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1temperature distribution and the resultant heat capacity infor-mation will be comparable with those of other non-oscillatorytest methods.5. Significance and Use5.1 Modulated temperature differential scanning calorimet-ric mea
17、surements provide a rapid, simple method for determin-ing specific heat capacities of materials, even under quasi-isothermal conditions.5.2 Specific heat capacities are important for designpurposes, quality control, and research and development.5.3 The use of a stepped quasi-isothermal program may b
18、eused to follow structure changes in materials.6. Interferences6.1 Since milligram quantities of specimen are used, it isessential that specimens are homogeneous and representative.6.2 The occurrence of chemical changes, or mass loss orgain, on heating during the measurement may invalidate thetest.
19、Therefore, the temperature range and specimen holdershould be chosen so as to avoid these processes.7. Apparatus7.1 Modulated Differential Scanning CalorimeterThe es-sential instrumentation required to provide the minimummodulated differential scanning calorimetric capability for thismethod includes
20、:7.1.1 A Modulated Temperature Differential Scanning Calo-rimeter (MTDSC) Test Chamber, composed of (1) a furnace toprovide uniform controlled heating/cooling of a specimen andreference to a constant temperature or at a constant rate withinthe applicable range 100 to 600C (2) a temperature sensor (o
21、rother signal source) to provide an indication of the specimentemperature readable to 0.01C; (3) a differential sensor todetect a heat flow difference between the specimen andreference equivalent to 1.0 W; and (4) a means of sustaining anenvironment of an inert purge gas at a rate of 50 6 10 mL/min.
22、(See 7.1.6 for more information on purge gases.)7.1.2 A Temperature Controller, capable of executing aspecific temperature program by (1) operating the furnacebetween selected temperature limits at a rate of temperaturechange of 1 to 10C/min, (2) holding at an isothermal tem-perature to within 60.1C
23、, and (3) sinusoidally varying thetemperature with an amplitude of up to 1.5C and a period ofup to 100 s (frequency down to 10 mHz) superimposed uponthe underlying rate.7.1.3 A Calculating Device, capable of transforming theexperimentally determined modulated temperature and modu-lated specimen heat
24、 flow signals into the required continuousoutput form of specific heat capacity (preferably in units ofJ/(gC) and average test temperature to the required accuracyand precision.7.1.4 A Data Collection Device, to provide a means ofacquiring, storing and displaying measured or calculatedsignals, or bo
25、th. The minimum output signals required forMTDSC are amplitude of modulated heat flow, temperature,amplitude of modulated temperature and time.7.1.5 A Coolant System, to provide oscillatory heating andcooling rates of at least 5C/min.7.1.6 Inert Nitrogen, or other low conductivity purge gasflowing a
26、t a rate of 50 mL/min.NOTE 1Helium, a commonly used purge gas, is unacceptable for thispurpose, due to its very high thermal conductivity which results in reducedrange, precision and accuracy.7.2 A Balance, with a range of at least 200 mg and aresolution of 60.001 mg to weigh specimens or containers
27、, orboth, (pans, crucibles, etc.) to an accuracy 60.01 mg.7.3 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.NOTE 2The masses of the specimen
28、holders should not differ by morethan 0.05 mg, otherwise the mass difference in the containers must beconsidered in the calculation of Cp.8. Reagents and Materials8.1 Specific heat capacity reference material: synthetic sap-phire disk, 10 to 100 mg.NOTE 3Interlaboratory studies have indicated that p
29、hysical forms ofsynthetic sapphire other than disks give lower precision and greater biasin the results.9. Hazards9.1 Safety PrecautionsIf a specimen is heated todecomposition, toxic or corrosive products may be released.9.2 Technical Precautions:9.2.1 The same modulation conditions of amplitude and
30、period should be used for both the heat capacity calibration andspecimen runs.9.2.2 Precision of heating rate, placement of the specimenholder, use of specimen holders with a flat base and theestablishment of equilibrium are essential. Instrument settingsshould not be adjusted once a specific heat c
31、apacity calibrationhas been performed.10. Sampling, Test Specimens, and Test Units10.1 Powdered or granular specimens should be mixed priorto sampling and should be sampled by removing portions fromvarious parts of the container. These portions, in turn, should becombined and mixed to ensure a repre
32、sentative specimen forthe determinations.10.2 Liquid specimens may be sampled directly after stir-ring.10.3 Solid specimens may be sampled by cutting or slicingwith a clean knife or razor blade. Ascertain sample uniformityas segregation within the solid sample is possible.10.4 Samples are usually an
33、alyzed as received. If somepre-conditioning or mechanical treatment is applied to the testspecimen prior to analysis, this should be noted in the report.11. Preparation of Apparatus11.1 Perform any setup or calibration procedures recom-mended by the apparatus manufacturer in the operationsmanual.E27
34、16 09 (2014)212. Calibration and Standardization12.1 Calibrate the temperature signal from the apparatus inaccordance with Test Method E967 using an indium referencematerial and a heating rate of 10C/min.12.2 Calibrate the heat flow signal from the apparatus inaccordance with Practice E968 using an
35、indium referencematerial.NOTE 4For both 12.1 and 12.2, another suitable reference materialmay be used to cover a different temperature range.12.3 Calibrate the apparatus heat capacity signal(s) forspecific heat capacity measurements under temperature modu-lated conditions in accordance with the inst
36、ructions of themanufacturer as described in the instrument manual.12.4 Select the temperature that, for Method A, is themid-point of the temperature range over which the measure-ment is to be made, or, for Method B, that is the temperature atwhich the measurement is to be made, or the midpoint of al
37、l theisothermal temperatures used in the measurement, if multipleisothermal temperatures are used.12.5 Crimp a clean, empty specimen holder plus lid andrecord the mass to a precision of 60.01 mg. Place on thereference side of the DSC.12.6 Weigh a clean, empty specimen holder plus lid to aprecision o
38、f 60.01 mg. Encapsulate the sapphire material from8.1 in this specimen holder. Record the mass of the sapphirestandard and specimen holder to a precision of 60.01 mg, andplace on the sample side of the instrument.Apply the followingtemperature modulation conditions: 61.0C amplitude, 100 speriod (10
39、mHz frequency) (if different modulation conditionsare used, they shall be reported). Hold the sample isothermalfor at least 10 minat the desired temperature and then measurethe heat capacity value at the end of the isotherm.12.7 Calculate the specific heat capacity constant (KCp)bytaking the ratio o
40、f the theoretical value of sapphire to themeasured value at the test temperature.NOTE 5Specific heat capacity values for synthetic sapphire may befound in Table 1 of Test Method E1269.13. Procedure13.1 Purge the DSC apparatus with dry nitrogen at a flowrate of 50 6 10 mL/min throughout the experimen
41、t.13.2 Crimp a clean, empty specimen holder plus lid andplace on the reference of the MTDSC apparatus. Record themass of the specimen holder plus lid to a precision of 60.01mg if required for proper operation of the DSC apparatus.13.3 Weigh a clean, empty specimen holder plus lid to aprecision of 60
42、.01 mg. Record as the tare weight.13.4 Encapsulate the sample to be studied into the specimenholder plus lid combination and record the mass of the sampleplus specimen holder and lid to 60.01 mg. Calculate thesample mass to 60.01 mg.13.5 Method A:13.5.1 Beginning 30C below the lowest temperature ofi
43、nterest to 10C above the highest temperature of interest,execute a ramped modulated DSC experiment over the tem-perature range of interest using the following modulatedparameters: 61.0C amplitude, 100 s period (10 mHzfrequency), and 3C/min heating rate (if different modulationconditions are used, th
44、ey should be reported).13.5.2 Record the amplitude of the modulated heat flow andthe amplitude of the modulated temperature continually or atthe temperature of interest.13.5.3 Using the amplitude of the modulated heat flow andamplitude of the modulated temperature from 13.5.2, calculateand report th
45、e specific heat capacity at the temperature ofinterest as described in Section 14.13.5.4 Re-weigh the specimen holder plus specimen. If amass loss of 0.3 % or greater occurred with respect to the initialmass, the measurement is invalid. Any change in mass shall bereported.13.6 Method B:13.6.1 Establ
46、ish the isothermal test temperature of interest.Initiate a temperature modulation of 61.0C amplitude, 100 speriod (10 mHz frequency) (if different modulation conditionsare used, they should be reported). After 10 minutes oftemperature modulation, record and report the heat capacity.13.6.2 Record the
47、 amplitude of the modulated heat flow andthe amplitude of the modulated temperature continually or atthe temperature of interest.13.6.3 Using the amplitude of the modulated heat flow andamplitude of the modulated temperature from 13.5.2, calculateand report the specific heat capacity at the temperat
48、ure ofinterest as described in Section 14.13.6.4 Re-weigh the specimen holder plus specimen. If amass loss of 0.3 % or greater occurred with respect to the initialmass, the measurement is invalid. Any change in mass shall bereported.14. Calculation or Interpretation of Results14.1 At the temperature
49、s of interest, measure the amplitudeof the modulated heat flow and record to the nearest 60.01mW.14.2 At the same temperatures in 14.1, measure the ampli-tude of the modulated heating rate to the nearest 60.01C/min.14.3 Calculate the specific heat capacity as follows:Cps560s/minAmhfKCp!/AmhrWs! (1)where:Cps= Specific heat capacity of the specimen, J/g C,Amhf= Amplitude of the modulated heat flow calculated in14.1,mW,Amhr= Amplitude of the modulated heating rate calculatedin 14.2,C/min,Ws= Mass of the sample specimen, mg, andKCp= Calibration consta
