ASTM D3418-21
(Test Method)Standard Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry
Standard Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry
SIGNIFICANCE AND USE
5.1 Thermal analysis provides a rapid method for measuring transitions due to morphological or chemical changes in a polymer as it is heated/cooled at a controlled rate through a specified temperature range. Change in specific heat capacity, heat flow and temperature values are determined for these transitions. Differential scanning calorimetry is used to assist in identifying specific polymers, polymer alloys, and certain polymer additives, which exhibit thermal transitions. Chemical reactions that cause or affect certain transitions have been measured with the aid of this technique; such reactions include oxidation, curing of thermosetting resins, and thermal decomposition.
5.2 This test method is useful for specification acceptance, process control, and research.
SCOPE
1.1 This test method covers determination of transition temperatures and enthalpies of fusion and crystallization of polymers by differential scanning calorimetry.
Note 1: True heats of fusion are to be determined in conjunction with structure investigation, and frequently, specialized crystallization techniques are needed.
1.2 This test method is applicable to polymers in granular form or to any fabricated shape from which it is possible to cut appropriate specimens.
1.3 The normal operating temperature range is from the cryogenic region to 600°C. Certain equipment allows the temperature range to be extended.
1.4 The values stated in SI units are the standard.
Note 2: This test method does not apply to all types of polymers as written (see 6.8).
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
Note 3: This standard is similar but not equivalent to ISO 11357-1, -2, -3. The ISO procedures provide additional information not supplied by this test method.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D3418 − 21
Standard Test Method for
Transition Temperatures and Enthalpies of Fusion and
Crystallization of Polymers by Differential Scanning
Calorimetry
This standard is issued under the fixed designation D3418; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers determination of transition
E473 Terminology Relating to Thermal Analysis and Rhe-
temperatures and enthalpies of fusion and crystallization of
ology
polymers by differential scanning calorimetry.
E691 Practice for Conducting an Interlaboratory Study to
NOTE 1—True heats of fusion are to be determined in conjunction with
Determine the Precision of a Test Method
structure investigation, and frequently, specialized crystallization tech-
niques are needed. E967 Test Method for Temperature Calibration of Differen-
tial Scanning Calorimeters and Differential Thermal Ana-
1.2 This test method is applicable to polymers in granular
lyzers
form or to any fabricated shape from which it is possible to cut
E968 Practice for Heat Flow Calibration of Differential
appropriate specimens.
Scanning Calorimeters
E1142 Terminology Relating to Thermophysical Properties
1.3 The normal operating temperature range is from the
cryogenic region to 600°C. Certain equipment allows the E1953 Practice for Description of Thermal Analysis and
Rheology Apparatus
temperature range to be extended.
2.2 ISO Standards:
1.4 The values stated in SI units are the standard.
ISO 11357-1 Plastics—Differential Scanning Calorimetry
NOTE 2—This test method does not apply to all types of polymers as
(DSC)—Part 1: General Principles
written (see 6.8).
ISO 11357-2 Plastics—Differential Scanning Calorimetry
1.5 This standard does not purport to address all of the
(DSC)—Part 2: Determination of Glass Transition Tem-
safety concerns, if any, associated with its use. It is the
perature
responsibility of the user of this standard to establish appro-
ISO 11357-3 Plastics—Differential Scanning Calorimetry
priate safety, health, and environmental practices and deter-
(DSC)—Part 3: Determination of Temperature and En-
mine the applicability of regulatory limitations prior to use.
thalpy of Melting and Crystallization
NOTE3—ThisstandardissimilarbutnotequivalenttoISO 11357-1,-2,
3. Terminology
-3. The ISO procedures provide additional information not supplied by
this test method. 3.1 Specialized terms used in this test method are defined in
Terminologies E473 and E1142.
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Summary of Test Method
ization established in the Decision on Principles for the
4.1 This test method consists of heating or cooling the test
Development of International Standards, Guides and Recom-
material at a controlled rate under a specified purge gas at a
mendations issued by the World Trade Organization Technical
controlled flow rate and continuously monitoring with a
Barriers to Trade (TBT) Committee.
suitable sensing device the difference in heat input between a
1 2
This test method is under the jurisdiction ofASTM Committee D20 on Plastics For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and is the direct responsibility of Subcommittee D20.30 on Thermal Properties contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
(Section D20.30.07). Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Sept. 1, 2021. Published September 2021. Originally the ASTM website.
approved in 1975. Last previous edition approved in 2015 as D3418 - 15. DOI: Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/D3418-21. 4th Floor, New York, NY 10036, http://www.ansi.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3418 − 21
reference material and a test material due to energy changes in crystallization is only possible from solution. For other poly-
the material.Atransition is marked by absorption or release of mers such as crystallizable polystyrene, annealing is only
energy by the specimen resulting in a corresponding endother- possible above their glass transition temperatures. When this
mic or exothermic peak or baseline shift in the heating or test method is used for polymers of this type, carefully
cooling curve. Areas under the crystallization exotherm or annealed samples must be tested without conditioning.
fusionendothermofthetestmaterialsarecomparedagainstthe
respective areas obtained by the treatment of a well-
7. Apparatus
characterized standard.
7.1 DifferentialScanningCalorimeter(DSC)—Theessential
instrumentation required to provide the minimum differential
5. Significance and Use
scanning calorimetric capability for this test method includes:
5.1 Thermalanalysisprovidesarapidmethodformeasuring
7.1.1 DSCTestChamber—This chamber is composed of the
transitions due to morphological or chemical changes in a
following:
polymer as it is heated/cooled at a controlled rate through a
7.1.1.1 Furnace(s), to provide uniform controlled heating
specified temperature range. Change in specific heat capacity,
(cooling)ofaspecimenandreferencetoaconstanttemperature
heat flow and temperature values are determined for these
or at a constant rate within the applicable cryogenic to 600°C
transitions.Differentialscanningcalorimetryisusedtoassistin
temperature range of this test method.
identifying specific polymers, polymer alloys, and certain
7.1.1.2 Temperature Sensor, to provide an indication of the
polymer additives, which exhibit thermal transitions. Chemical
specimen temperature to 60.01°C.
reactions that cause or affect certain transitions have been
7.1.1.3 Differential Sensor, to detect heat flow difference
measured with the aid of this technique; such reactions include
between the specimen and reference equivalent to 1 mW.
oxidation, curing of thermosetting resins, and thermal decom-
7.1.1.4 MeansofSustainingaTestChamberEnvironmentof
position.
purge gas at a purge flow rate of 10 to 50 6 5 mL/min.
5.2 This test method is useful for specification acceptance,
NOTE4—Typically,99+ %purenitrogen,argonorheliumareemployed
process control, and research.
when oxidation in air is a concern. Unless effects of moisture are to be
studied, use of dry purge gas is recommended and is essential for
6. Interferences
operation at sub-ambient temperatures.
6.1 Differences in heating or cooling rate as well as the final
7.1.2 Temperature Controller, capable of executing a spe-
heating and cooling temperature have an effect on the mea-
cific temperature program by operating the furnace(s) between
sured results, especially on the enthalpy of fusion or crystalli-
selected temperature limits at a rate of temperature change of
zation. Therefore, departure from conditions specified for a
0.5 to 20°C/min constant to 60.1°C/min or at an isothermal
given polymer is not permitted.
temperature constant to 60.1°C.
6.2 The presence of impurities is known to affect the
7.1.3 Recording Device, capable of recording and display-
transition temperature, particularly if an impurity tends to form
ing any fraction of the heat flow signal (DSC curve) including
solid solutions, or to be miscible in the melt phase.
the signal noise as a function of temperature.
7.1.4 Software, for integrating areas under endothermic
6.3 Uncertain radiation losses at temperatures higher than
valleys or exothermic peaks, or both.
400°C have been known to affect the accuracy of results at
7.1.5 Containers(pans,crucibles,andsoforth)thatareinert
times.
tothespecimenandreferencematerials;andthatareofsuitable
6.4 Since particle size has an effect upon detected transition
structural shape and integrity to contain the specimen and
temperatures, the specimens to be compared shall be approxi-
reference in accordance with the specific requirements of this
mately the same particle size (1-5).
test method.
6.5 In cases that specimens react with air during the
7.1.6 Cooling capability to hasten cool down from elevated
temperature cycle, provision shall be made for running the test
temperatures, to provide constant cooling rates of 0.5 - 20
under an inert gas blanket to avoid any incorrect measurement.
ºC/min to obtain repeatable crystallization temperatures, to
Since some materials degrade near the melting region, care
achieve sub-ambient operation, or to sustain an isothermal
mustbeusedtodistinguishbetweendegradationandtransition.
sub-ambient temperature, or combination thereof.
6.6 Since milligram quantities of a specimen are used, it is
7.2 Balance, capable of weighing to 60.0001 grams for
essential to ensure that specimens are homogeneous and
transition temperatures and to 60.00001 grams for determin-
representative.
ing enthalpies.
6.7 Itispossiblethattoxicorcorrosiveeffluentsarereleased
when heating the material, and be harmful to the personnel or 8. Sample
to the apparatus.
8.1 Powdered or Granular Specimens—Avoid grinding if
6.8 Not all polymers lend themselves to the exact terms of the preliminary thermal cycle as outlined in 10.1.3 is not
this test method. For some polymers such as polyarylamides,
performed. Grinding or similar techniques for size reduction
often introduce thermal effects because of friction or
orientation, or both, and thereby change the thermal history of
The boldface numbers in parentheses refer to the list of references at the end of
this test method. the specimen.
D3418 − 21
TABLE 1 Effect of Rate of Temperature Rise on Transition Temperatures
Material Rate of Temperature T Second Heat (°C) T (°C) T First Heat (°C) T Second Heat (°C)
g c m m
Rise (°C / Min.)
PEEK 5 Too Weak 298.1 342.2 341.7
PEEK 10 Too Weak 293.4 339.4 340.2
PEEK 20 150.6 287.2 339.0 338.7
PEEK 40 156.0 277.7 341.4 338.2
Syndiotactic PP 5 Non Observed 75.0 131.1 130.7
Syndiotactic PP 10 Non Observed 70.0 129.4 129.8
Syndiotactic PP 20 Non Observed 64.9 127.9 129.1
Syndiotactic PP 40 Non Observed 58.8 130.1 130.4
8.2 Molded or Pelleted Specimens—Cut the specimens with 10.1.3 Perform and record a preliminary thermal cycle by
a microtome, razor blade, hypodermic punch, paper punch, or heating the sample at the same rate used for testing from at
cork borer (Size No. 2 or 3) or other appropriate means to least 50°C below to 30°C above the melting temperature to
appropriate size, in thickness or diameter and length that will erase previous thermal history.
best fit the specimen containers as in 7.1.5 and will approxi- 10.1.4 When the effect of annealing is studied, selection of
mately meet the desired weight in the subsequent procedure.
temperature and time are critical. Minimize the time of
exposure to high temperature to avoid sublimation or decom-
8.3 FilmorSheetSpecimens—For films thicker than 40 µm,
position. In some cases it is possible that the preliminary
see 8.2. For thinner films, cut slivers to fit in the specimen
thermal cycle will interfere with the transition of interest,
capsules or punch disks, if the circular specimen capsules are
causing an incorrect transition or eliminating a transition.
used.
Where it has been shown that this effect is present, omit the
8.4 Use any shape or form listed in 8.1 – 8.3 except when
preliminary thermal cycle.
conducting referee tests that shall be performed on films as
10.1.5 Hold the temperature for 5 min (10.1.3).
specified in 8.3.
NOTE 6—In cases that high-temperature annealing cause polymer
degradation, the use of shorter annealing times is permitted but shall be
9. Calibration
reported.
9.1 The purge gas shall be used during calibration.
10.1.6 Cool to at least 50°C below the peak crystallization
9.2 Calibrate the DSC temperature signal using Practice
temperature using the same rate that was used for heating and
E967 and the same heating rate to be used in this test method
record the cooling curve.
preferably10°C/minor20°C/min(seeNote5).(SeeSection10
10.1.7 Hold the temperature for 5 min.
for details.)
10.1.8 Repeat heating at the same rate used in 10.1.3
(10°C/min or 20°C/min) and record the heating curve. Use this
9.3 Calibrate the DSC heat flow signal using Practice E968
curve to calculate the enthalpies of transition.
and the same heating rate as in 9.2 (see Note 5).
10.1.9 Measure the temperatures for the desired points on
9.4 Some instruments allow for the temperature and heat
the curves: T ,T ,T ,T ,T , and T (see Fig. 1).
eim pm efm eic pc eic
flow calibration to be performed simultaneously. In such cases,
Report two T ’s or T ’s if observed.
pm pc
use the same heating rate for this method and follow the
10.1.10 In case of dispute determine T and T at a heating
m c
manufacturer’s instruction. Report the heating rate. (See
rate of 10°C/min.
12.1.3.)
NOTE 5—Use of other heating rates is permitted. However, test results
where:
are affected by the heating rate. See Table 1. It is the responsibility of the
T = melting extrapolated onset temperature, °C,
user of other rates to demonstrate equivalency to this test method. eim
T = melting extrapolated end temperature, °C,
efm
T = melting peak temperature,° C,
10. Procedure pm
T = crystallization extrapolated onset temperature, °C,
eic
10.1 For First-Order Transition (melting and crystalliza-
T = crystallization peak temperature, °C, and
pc
tion):
T = crystallization extrapolated end temperature, °C.
efc
10.1.1 The purge gas shall be used during testing. The flow
NOTE 7—The actual temperature displayed on the temperature axis
rateofthegasshallbethesameasusedinthecalibration(9.1).
depends upon the instrument type (for example, specimen temperature,
program temperature, or specimen-program temperature average). Follow
10.1.2 Use a specimen mass appropriate for the material to
any recommended procedures or guidelines of the instrument manufac-
be tested. In most cases a 5-mg specimen mass is satisfactory.
turer to obtain specimen temperature at the point of interest.
Avoid overloading.Weigh the specimen to an accuracy of 610
10.2 For Glass Transition:
µg.
10.1.2.1 Intimate thermal contact between the pan and 10.2.1 The pu
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D3418 − 15 D3418 − 21
Standard Test Method for
Transition Temperatures and Enthalpies of Fusion and
Crystallization of Polymers by Differential Scanning
Calorimetry
This standard is issued under the fixed designation D3418; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This test method covers determination of transition temperatures and enthalpies of fusion and crystallization of polymers by
differential scanning calorimetry.
NOTE 1—True heats of fusion are to be determined in conjunction with structure investigation, and frequently, specialized crystallization techniques are
needed.
1.2 This test method is applicable to polymers in granular form or to any fabricated shape from which it is possible to cut
appropriate specimens.
1.3 The normal operating temperature range is from the cryogenic region to 600°C. Certain equipment allows the temperature
range to be extended.
1.4 The values stated in SI units are the standard.
NOTE 2—This test method does not apply to all types of polymers as written (see 6.8).
1.5 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
NOTE 3—This standard is similar but not equivalent to ISO 11357-1, -2, -3. The ISO procedures provide additional information not supplied by this test
method.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.30 on Thermal Properties (Section
D20.30.07).
Current edition approved May 1, 2015Sept. 1, 2021. Published June 2015September 2021. Originally approved in 1975. Last previous edition approved in 20122015 as
ε1
D3418 - 12D3418 - 15. . DOI: 10.1520/D3418-15.10.1520/D3418-21.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3418 − 21
2. Referenced Documents
2.1 ASTM Standards:
E473 Terminology Relating to Thermal Analysis and Rheology
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E967 Test Method for Temperature Calibration of Differential Scanning Calorimeters and Differential Thermal Analyzers
E968 Practice for Heat Flow Calibration of Differential Scanning Calorimeters
E1142 Terminology Relating to Thermophysical Properties
E1953 Practice for Description of Thermal Analysis and Rheology Apparatus
2.2 ISO Standards:
ISO 11357-1 Plastics—Differential Scanning Calorimetry (DSC)—Part 1: General Principles
ISO 11357-2 Plastics—Differential Scanning Calorimetry (DSC)—Part 2: Determination of Glass Transition Temperature
ISO 11357-3 Plastics—Differential Scanning Calorimetry (DSC)—Part 3: Determination of Temperature and Enthalpy of
Melting and Crystallization
3. Terminology
3.1 Specialized terms used in this test method are defined in Terminologies E473 and E1142.
4. Summary of Test Method
4.1 This test method consists of heating or cooling the test material at a controlled rate under a specified purge gas at a controlled
flow rate and continuously monitoring with a suitable sensing device the difference in heat input between a reference material and
a test material due to energy changes in the material. A transition is marked by absorption or release of energy by the specimen
resulting in a corresponding endothermic or exothermic peak or baseline shift in the heating or cooling curve. Areas under the
crystallization exotherm or fusion endotherm of the test materials are compared against the respective areas obtained by the
treatment of a well-characterized standard.
5. Significance and Use
5.1 Thermal analysis provides a rapid method for measuring transitions due to morphological or chemical changes,changes in a
polymer as it is heated/cooled at a controlled rate through a specified temperature range. Change in specific heat capacity, heat flow
and temperature values are determined for these transitions. Differential scanning calorimetry is used to assist in identifying
specific polymers, polymer alloys, and certain polymer additives, which exhibit thermal transitions. Chemical reactions that cause
or affect certain transitions have been measured with the aid of this technique; such reactions include oxidation, curing of
thermosetting resins, and thermal decomposition.
5.2 This test method is useful for specification acceptance, process control, and research.
6. Interferences
6.1 Differences in heating or cooling rate as well as the final heating and cooling temperature have an effect on the measured
results, especially on the enthalpy of fusion or crystallization. Therefore, departure from conditions specified for a given polymer
is not permitted.
6.2 The presence of impurities is known to affect the transition temperature, particularly if an impurity tends to form solid
solutions, or to be miscible in the melt phase.
6.3 Uncertain radiation losses at temperatures higher than 400°C have been known to affect the accuracy of results at times.
6.4 Since particle size has an effect upon detected transition temperatures, the specimens to be compared shall be approximately
the same particle size (1-5).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
The boldface numbers in parentheses refer to the list of references at the end of this test method.
D3418 − 21
6.5 In cases that specimens react with air during the temperature cycle, provision shall be made for running the test under an inert
gas blanket to avoid any incorrect measurement. Since some materials degrade near the melting region, care must be used to
distinguish between degradation and transition.
6.6 Since milligram quantities of a specimen are used, it is essential to ensure that specimens are homogeneous and representative.
6.7 It is possible that toxic or corrosive effluents are released when heating the material, and be harmful to the personnel or to the
apparatus.
6.8 Not all polymers lend themselves to the exact terms of this test method. For some polymers such as polyarylamides,
crystallization is only possible from solution. For other polymers such as crystallizable polystyrene, annealing is only possible
above their glass transition temperatures. When this test method is used for polymers of this type, carefully annealed samples must
be tested without conditioning.
7. Apparatus
7.1 Differential Scanning Calorimeter (DSC)—The essential instrumentation required to provide the minimum differential
scanning calorimetric capability for this test method includes:
7.1.1 DSC Test Chamber—This chamber is composed of the following:
7.1.1.1 Furnace(s), to provide uniform controlled heating (cooling) of a specimen and reference to a constant temperature or at
a constant rate within the applicable cryogenic to 600°C temperature range of this test method.
7.1.1.2 Temperature Sensor, to provide an indication of the specimen temperature to 60.01°C.
7.1.1.3 Differential Sensor, to detect heat flow difference between the specimen and reference equivalent to 1 mW.
7.1.1.4 Means of Sustaining a Test Chamber Environment of purge gas at a purge flow rate of 10 to 50 6 5 mL/min.
NOTE 4—Typically, 99+ % pure nitrogen, argon or helium are employed when oxidation in air is a concern. Unless effects of moisture are to be studied,
use of dry purge gas is recommended and is essential for operation at sub-ambient temperatures.
7.1.2 Temperature Controller, capable of executing a specific temperature program by operating the furnace(s) between selected
temperature limits at a rate of temperature change of 0.5 to 20°C/min constant to 60.1°C/min or at an isothermal temperature
constant to 60.1°C.
7.1.3 Recording Device, capable of recording and displaying any fraction of the heat flow signal (DSC curve) including the signal
noise as a function of temperature.
7.1.4 Software, for integrating areas under endothermic valleys or exothermic peaks, or both.
7.1.5 Containers (pans, crucibles, and so forth) that are inert to the specimen and reference materials; and that are of suitable
structural shape and integrity to contain the specimen and reference in accordance with the specific requirements of this test
method.
7.1.6 Cooling capability to hasten cool down from elevated temperatures, to provide constant cooling rates of 0.5 - 20 ºC/min to
obtain repeatable crystallization temperatures, to achieve sub-ambient operation, or to sustain an isothermal sub-ambient
temperature, or combination thereof.
7.2 Balance, capable of weighing to 60.0001 grams for transition temperatures and to 60.00001 grams for determining
enthalpies.
D3418 − 21
TABLE 1 Effect of Rate of Temperature Rise on Transition Temperatures
Material Rate of Temperature T Second Heat (°C) T (°C) T First Heat (°C) T Second Heat (°C)
g c m m
Rise (°C / Min.)
PEEK 5 Too Weak 298.1 342.2 341.7
PEEK 10 Too Weak 293.4 339.4 340.2
PEEK 20 150.6 287.2 339.0 338.7
PEEK 40 156.0 277.7 341.4 338.2
Syndiotactic PP 5 Non Observed 75.0 131.1 130.7
Syndiotactic PP 10 Non Observed 70.0 129.4 129.8
Syndiotactic PP 20 Non Observed 64.9 127.9 129.1
Syndiotactic PP 40 Non Observed 58.8 130.1 130.4
8. Sample
8.1 Powdered or Granular Specimens—Avoid grinding if the preliminary thermal cycle as outlined in 10.1.3 is not performed.
Grinding or similar techniques for size reduction often introduce thermal effects because of friction or orientation, or both, and
thereby change the thermal history of the specimen.
8.2 Molded or Pelleted Specimens—Cut the specimens with a microtome, razor blade, hypodermic punch, paper punch, or cork
borer (Size No. 2 or 3) or other appropriate means to appropriate size, in thickness or diameter and length that will best fit the
specimen containers as in 7.1.5 and will approximately meet the desired weight in the subsequent procedure.
8.3 Film or Sheet Specimens—For films thicker than 40 μm, see 8.2. For thinner films, cut slivers to fit in the specimen capsules
or punch disks, if the circular specimen capsules are used.
8.4 Use any shape or form listed in 8.1 – 8.3 except when conducting referee tests that shall be performed on films as specified
in 8.3.
9. Calibration
9.1 The purge gas shall be used during calibration.
9.2 Calibrate the DSC temperature signal using Practice E967 and the same heating rate to be used in this test method preferably
10°C/min or 20°C/min (see Note 5). (See Section 10 for details.)
9.3 Calibrate the DSC heat flow signal using Practice E968 and the same heating rate as in 9.2 (see Note 5).
9.4 Some instruments allow for the temperature and heat flow calibration to be performed simultaneously. In such cases, use the
same heating rate for this method and follow the manufacturer’s instruction. Report the heating rate. (See 12.1.3.)
NOTE 5—Use of other heating rates is permitted. However, test results are affected by the heating rate. See Table 1. It is the responsibility of the user
of other rates to demonstrate equivalency to this test method.
10. Procedure
10.1 For First-Order Transition (melting and crystallization):
10.1.1 The purge gas shall be used during testing. The flow rate of the gas shall be the same as used in the calibration (9.1).
10.1.2 Use a specimen mass appropriate for the material to be tested. In most cases a 5-mg specimen mass is satisfactory. Avoid
overloading. Weigh the specimen to an accuracy of 610 μg.
10.1.2.1 Intimate thermal contact between the pan and specimen is essential for reproducible results. Crimp a metal cover against
the pan with the sample sandwiched in between to ensure good heat transfer. Take care to ensure flat pan bottoms.
10.1.3 Perform and record a preliminary thermal cycle by heating the sample at the same rate used for testing from at least 50°C
below to 30°C above the melting temperature to erase previous thermal history.
D3418 − 21
FIG. 1 First-Order Transition of Nylon
10.1.4 When the effect of annealing is studied, selection of temperature and time are critical. Minimize the time of exposure to
high temperature to avoid sublimation or decomposition. In some cases it is possible that the preliminary thermal cycle will
interfere with the transition of interest, causing an incorrect transition or eliminating a transition. Where it has been shown that
this effect is present, omit the preliminary thermal cycle.
10.1.5 Hold the temperature for 5 min (10.1.3).
NOTE 6—In cases that high-temperature annealing cause polymer degradation, the use of shorter annealing times is permitted but shall be reported.
10.1.6 Cool to at least 50°C below the peak crystallization temperature using the same rate that was used for heating and record
the cooling curve.
10.1.7 Hold the temperature for 5 min.
10.1.8 Repeat heating at the same rate used in 10.1.3 (10°C/min or 20°C/min) and record the heating curve. Use this curve to
calculate the enthalpies of transition.
10.1.9 Measure the temperatures for the desired points on the curves: T , T , T , T , T , and T (see Fig. 1). Report two
eim pm efm eic pc eic
T ’s or T ’s if observed.
pm pc
10.1.10 In case of dispute determine T and T at a heating rate of 10°C/min.
m c
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