ASTM E793-06(2012)
(Test Method)Standard Test Method for Enthalpies of Fusion and Crystallization by Differential Scanning Calorimetry
Standard Test Method for Enthalpies of Fusion and Crystallization by Differential Scanning Calorimetry
SIGNIFICANCE AND USE
5.1 Differential scanning calorimetry provides a rapid method for the determination of enthalpic changes accompanying first-order transitions of materials.
5.2 This test method is useful for quality control, specification acceptance, and research.
SCOPE
1.1 This test method describes the determination of the enthalpy (heat) of fusion (melting) and crystallization by differential scanning calorimetry (DSC).
1.2 This test method is applicable to solid samples in granular form or in any fabricated shape from which an appropriate specimen can be cut, or to liquid samples that crystallize within the range of the instrument. Note, however, that the results may be affected by the form and mass of the specimen, as well as by other experimental conditions.
1.3 The normal operating temperature range is from −120 to 600°C. The temperature range can be extended depending upon the instrumentation used.
1.4 This test method is generally applicable to thermally stable materials with well defined endothermic or exothermic behavior.
1.5 Computer or electronic based instruments, techniques, or data treatment equivalent to those in this test method may also be used.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 The enthalpy of melting and crystallization portion of ISO 11357-3 is equivalent to this standard.
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E793 − 06 (Reapproved 2012)
Standard Test Method for
Enthalpies of Fusion and Crystallization by Differential
Scanning Calorimetry
This standard is issued under the fixed designation E793; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This test method describes the determination of the
enthalpy (heat) of fusion (melting) and crystallization by
2. Referenced Documents
differential scanning calorimetry (DSC).
2.1 ASTM Standards:
1.2 This test method is applicable to solid samples in
E473Terminology Relating to Thermal Analysis and Rhe-
granular form or in any fabricated shape from which an
ology
appropriate specimen can be cut, or to liquid samples that
E794TestMethodforMeltingAndCrystallizationTempera-
crystallize within the range of the instrument. Note, however,
tures By Thermal Analysis
that the results may be affected by the form and mass of the
E968Practice for Heat Flow Calibration of Differential
specimen, as well as by other experimental conditions.
Scanning Calorimeters
1.3 Thenormaloperatingtemperaturerangeisfrom−120to
E1142Terminology Relating to Thermophysical Properties
600°C. The temperature range can be extended depending
E1860Test Method for Elapsed Time Calibration of Ther-
upon the instrumentation used.
mal Analyzers
2.2 ISO Standard:
1.4 This test method is generally applicable to thermally
ISO 11357–3Plastics – Differential Scanning Calorimetry
stable materials with well defined endothermic or exothermic
(DSC)–Part3:TemperatureandEnthalpyofMeltingand
behavior.
Crystallization
1.5 Computer or electronic based instruments, techniques,
or data treatment equivalent to those in this test method may
3. Terminology
also be used.
3.1 Definitions—Specialized terms used in this test method
1.6 The values stated in SI units are to be regarded as
are defined in Terminologies E473 and E1142.
standard. No other units of measurement are included in this
standard. 4. Summary of Test Method
1.7 The enthalpy of melting and crystallization portion of
4.1 This test method involves heating (or cooling) a test
ISO 11357-3 is equivalent to this standard. specimen at a controlled rate in a controlled environment
throughthetemperatureregionoffusionorcrystallization.The
1.8 This standard does not purport to address all of the
heat flow associated with fusion, an endothermic process (and
safety concerns, if any, associated with its use. It is the
crystallization, an exothermic process), is recorded and inte-
responsibility of the user of this standard to establish appro-
grated over time. Absolute values for the enthalpy of fusion
priate safety and health practices and determine the applica-
(andenthalpyofcrystallization)orrelativevaluesforcompara-
bility of regulatory limitations prior to use.
tive purposes can thus be obtained.
1.9 This international standard was developed in accor-
dance with internationally recognized principles on standard-
NOTE 1—Melting (or crystallization) temperatures are sometimes de-
ization established in the Decision on Principles for the termined in conjunction with measurements of the enthalpy of fusion or
crystallization.ThesetemperaturevaluesmaybeobtainedbyTestMethod
Development of International Standards, Guides and Recom-
E794.
1 2
ThistestmethodisunderthejurisdictionofASTMCommitteeE37onThermal For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Measurements and is the direct responsibility of Subcommittee E37.01 on Calo- contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
rimetry and Mass Loss. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Sept. 1, 2012. Published September 2012. Originally the ASTM website.
approved in 1981. Last previous edition approved in 2006 as E793–06. DOI: Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/E0793-06R12. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E793 − 06 (2012)
5. Significance and Use 6.5.3 A cooling capability to hasten cool down from el-
evated temperatures, to provide constant cooling rates, or to
5.1 Differential scanning calorimetry provides a rapid
sustain an isothermal subambient temperature.
method for the determination of enthalpic changes accompa-
nying first-order transitions of materials.
7. Hazards and Interferences
5.2 This test method is useful for quality control, specifica-
7.1 Since milligram quantities of specimens are used, it is
tion acceptance, and research.
essential that samples are homogeneous.
7.2 Toxic or corrosive effluents, or both, may be released
6. Apparatus
when heating the material and could be harmful to the
6.1 DSC, The essential instrumentation required to provide
personnel or the apparatus.
the minimum differential scanning calorimetric capability for
7.3 Samples that release volatiles upon heating will change
this method includes:
mass and invalidate the test.
6.1.1 DSC Test Chamber composed of:
7.4 In the use of commercial instrumentation, the operator
6.1.1.1 a furnace(s), to provide uniform controlled heating
should read the manufacturer’s operations manual to be aware
and cooling of a specimen and reference to a constant
of potential hazards of operation, such as burn hazards from
temperature or at a constant rate from –120 to 600°C.
hot surfaces.
6.1.1.2 Atemperature sensor,toprovideanindicationofthe
specimen temperature to 60.1°C.
8. Sampling
6.1.1.3 Differential sensors, to detect a heat flow difference
8.1 Powdered or granular materials should be mixed thor-
between specimen and reference with a range of at least 6100
oughly prior to sampling and should be sampled by removing
mW and a sensitivity of 65mW.
portions from various parts of the container.These portions, in
6.1.1.4 A means of sustaining a test chamber environment
turn, should be combined and mixed well to ensure a repre-
of an inert purge gas as at rate of 10 to 50 6 5 mL/min.
sentative specimen for the determination. Liquid samples may
be sampled directly after mixing.
NOTE 2—Typically, 99.99+% pure nitrogen, argon or helium is used
when oxidation in air is a concern. Unless effects of moisture are to be
8.2 In the absence of other information, samples are as-
studied, use of dry purge gas is recommended and is essential for
sumed to be analyzed as received. If some heat or mechanical
operation at subambient temperatures.
treatment is applied to the sample prior to analysis, this
6.1.2 A temperature controller, capable of executing a
treatment, and any mass loss resulting from this treatment,
specific temperature program by operating the furnaces(s)
should be noted in the report.
between selected temperature limits at a rate of temperature
change of up to at least 20°C/min constant to 60.1°C/min. or
9. Calibration
at an isothermal temperature constant to 60.1°C.
9.1 Using the same heating rate, purge gas, and flow rate to
6.1.3 A recording device, capable of recording and display-
be used for specimens, calibrate the heat flow axis of the
ing on the Y-axis any portion of the heat flow signal (DSC
instrument, using the procedure in Practice E968.
curve)includingthesignalnoiseasafunctionofanyportionof
9.2 Calibrate the elapsed time signal of the differential
the temperature or time signal on the X-axis including the
scanning calorimeter using Test Method E1860.
signal noise.
6.2 Specimen Containers, (pans, crucibles, vials, lids,
10. Procedure
closures,seals,etc.)thatareinerttothespecimenandreference
10.1 Weigh 1 to 15 mg of specimen to an accuracy of 60.1
materials and that are of suitable structural shape and integrity
% into a clean, dry specimen capsule.
to contain the specimen and reference.
NOTE 4—The specimen mass to be used depends on the magnitude of
6.3 Nitrogen,orotherinertgassupplyforpurgingpurposes.
the transition enthalpy and the volume of the capsule. For comparing
multiple results, use similar mass (65 %) and encapsulation.Weighing to
6.4 Balance, with capacity greater than 100 mg, capable of
less accuracy than one part per thousand may limit the accuracy of the
weighing to the nearest 0.01 mg, or better.
enthalpy determination.
NOTE 3—Balances readable to 0.01 mg are suitable for use with test 10.2 Seal or crimp the specimen capsule with a lid under
specimens on the order of 10 mg in mass.Abalance readable to 0.001 mg
ambient conditions. Minimize the free space between the
isrequiredfortestspecimensontheorderof1mginmass.toachievethe
specimen and the lid. For specimens sensitive to oxidation,
precision described in this standard.
hermetic sealing under an inert atmosphere may be desirable.
6.5 Auxiliary instrumentation considered useful or neces-
10.3 Load the specimen into the instrument chamber. Purge
sary for conducting this method includes:
thechamberwithdrynitrogen(orotherinertgas)ataflowrate
6.5.1
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