ASTM E1952-23

Standard Test Method for Thermal Conductivity and Thermal Diffusivity by Modulated Temperature Differential Scanning Calorimetry

SIGNIFICANCE AND USE
5.1 Thermal conductivity is a useful design parameter for the rate of heat transfer through a material.  
5.2 The results of this test method may be used for design purposes, service evaluation, manufacturing control, research and development, and hazard evaluation. (See Practice E1231.)
SCOPE
1.1 This test method describes the determination of thermal conductivity of homogeneous, non-porous solid materials in the range of 0.10 W/(K·m) to 1.0 W/(K·m) by modulated temperature differential scanning calorimeter. This range includes many polymeric, glass, and ceramic materials. Thermal diffusivity, which is related to thermal conductivity through specific heat capacity and density, may also be derived. Thermal conductivity and diffusivity can be determined at one or more temperatures over the range of 0 °C to 90 °C.  
1.2 The values stated in SI units are to be regarded as standard.  
1.3 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.  
1.4 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

• Status: Published
• Publication Date: 31-May-2023
• ICS: 17.200.10 - Heat. Calorimetry
• Technical Committee: E37 - Thermal Measurements
• Drafting Committee: E37.10 - Fundamental, Statistical and Mechanical Properties

Relations

• Refers: ASTM E1142-23b - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Oct-2023
• Refers: ASTM E473-23b - Standard Terminology Relating to Thermal Analysis and Rheology
• Effective Date: 01-Oct-2023
• Refers: ASTM E1231-19 - Standard Practice for Calculation of Hazard Potential Figures of Merit for Thermally Unstable Materials
• Effective Date: 01-Sep-2019
• Refers: ASTM E1231-15 - Standard Practice for Calculation of Hazard Potential Figures of Merit for Thermally Unstable Materials
• Effective Date: 01-Nov-2015
• Refers: ASTM E2161-15 - Standard Terminology Relating to Performance Validation in Thermal Analysis and Rheology
• Effective Date: 01-Sep-2015
• Refers: ASTM E1142-15 - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-May-2015
• Refers: ASTM E473-14 - Standard Terminology Relating to Thermal Analysis and Rheology
• Effective Date: 15-Aug-2014
• Refers: ASTM E1142-14b - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 15-Aug-2014
• Refers: ASTM E1142-14a - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Apr-2014
• Refers: ASTM E1142-14 - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 15-Feb-2014
• Refers: ASTM E2161-13 - Standard Terminology Relating to Performance Validation in Thermal Analysis
• Effective Date: 01-Mar-2013
• Refers: ASTM E1142-12 - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Sep-2012
• Refers: ASTM E1142-11b - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Aug-2011
• Refers: ASTM E473-11a - Standard Terminology Relating to Thermal Analysis and Rheology
• Effective Date: 15-Jun-2011
• Refers: ASTM E1142-11a - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 15-Jun-2011

Overview

ASTM E1952-23 is the internationally recognized standard test method for measuring the thermal conductivity and thermal diffusivity of homogeneous, non-porous solid materials using modulated temperature differential scanning calorimetry (MTDSC). This method is vital for accurately characterizing heat transport properties in polymeric, glass, and ceramic materials, especially within the thermal conductivity range of 0.10 W/(K·m) to 1.0 W/(K·m) and temperature range of 0 °C to 90 °C.

Thermal conductivity is a fundamental property essential for designing materials and systems where heat transfer efficiency, insulation, or dissipation is critical. This test provides actionable data for a range of industries, supporting design, quality control, and research initiatives.

Key Topics

• Thermal Conductivity Measurement: Defines procedures for determining the rate of heat transfer through solid materials via modulated temperature DSC, ensuring results are precise and repeatable.
• Thermal Diffusivity Calculation: Describes how thermal diffusivity-an indicator of how quickly a material responds to temperature changes-is derived from thermal conductivity, specific heat capacity, and density.
• Material Suitability: Applicable to homogeneous solids, particularly polymers, glasses, and ceramics-materials widely used in automotive, electronics, and construction sectors.
• Test Apparatus and Calibration: Specifies the use of a modulated temperature DSC and reference standards, and details calibration procedures to ensure measurement reliability.
• Data Reporting and Interpretation: Covers complete material identification, apparatus description, calibration constants, specimen geometry, and reporting of thermal conductivity and diffusivity at each test temperature.
• Precision and Variability: Addresses measurement repeatability within and between laboratories, as well as estimation and reporting of measurement uncertainty and bias.

Applications

ASTM E1952-23 is utilized across diverse fields for:

• Design and Engineering: Selecting materials based on their thermal properties for optimizing heat management in systems and products.
• Service Evaluation: Assessing in-service material performance for heat-sensitive applications.
• Manufacturing Control: Monitoring and ensuring material consistency during production by routine measurement of heat transfer properties.
• Research and Development: Supporting innovation by characterizing new materials or formulations where thermal performance is a priority.
• Hazard Evaluation: Assessing and comparing figures of merit for thermal instability, which is crucial in evaluating process and product safety (with reference to ASTM E1231).

Industries that benefit from this standard include automotive, aerospace, electronics, building materials, and any sector where precise thermal analysis improves product quality, safety, and efficiency.

Related Standards

ASTM E1952-23 directly references and complements several other ASTM standards relevant to thermal analysis and heat flow measurement:

• ASTM E473: Terminology Relating to Thermal Analysis and Rheology
• ASTM E967: Test Method for Temperature Calibration of Differential Scanning Calorimeters and Differential Thermal Analyzers
• ASTM E1142: Terminology Relating to Thermophysical Properties
• ASTM E1231: Practice for Calculation of Hazard Potential Figures of Merit for Thermally Unstable Materials
• ASTM E2161: Terminology Relating to Performance Validation in Thermal Analysis and Rheology

Adherence to these standards ensures consistency and comparability in thermal property measurements worldwide.

---

Keywords: thermal conductivity, thermal diffusivity, modulated temperature differential scanning calorimetry, MTDSC, ASTM E1952-23, polymers, ceramics, glasses, heat transfer, materials testing, thermal analysis, standard methods.

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: E1952 − 23
Standard Test Method for
Thermal Conductivity and Thermal Diffusivity by Modulated
Temperature Differential Scanning Calorimetry
This standard is issued under the fixed designation E1952; 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.
1. Scope Scanning Calorimeters (Withdrawn 2023)
E1142 Terminology Relating to Thermophysical Properties
1.1 This test method describes the determination of thermal
E1231 Practice for Calculation of Hazard Potential Figures
conductivity of homogeneous, non-porous solid materials in
of Merit for Thermally Unstable Materials
the range of 0.10 W/(K·m) to 1.0 W ⁄(K·m) by modulated
E2161 Terminology Relating to Performance Validation in
temperature differential scanning calorimeter. This range in-
Thermal Analysis and Rheology
cludes many polymeric, glass, and ceramic materials. Thermal
diffusivity, which is related to thermal conductivity through
3. Terminology
specific heat capacity and density, may also be derived.
3.1 Definitions:
Thermal conductivity and diffusivity can be determined at one
3.1.1 Specific technical terms used in this test method are
or more temperatures over the range of 0 °C to 90 °C.
defined in Terminologies E473, E1142, and E2161 including
1.2 The values stated in SI units are to be regarded as
calibration, differential scanning calorimetry, heat capacity,
standard.
modulated temperature, precision, reference material, relative
1.3 This standard does not purport to address all of the
standard deviation, repeatability, reproducibility, specific heat
safety concerns, if any, associated with its use. It is the
capacity, standard deviation, thermal analysis, thermal
responsibility of the user of this standard to establish appro-
conductance, and thermal conductivity.
priate safety, health, and environmental practices and deter-
3.2 Definitions of Terms Specific to This Standard:
mine the applicability of regulatory limitations prior to use.
3.2.1 modulated temperature differential scanning
1.4 This international standard was developed in accor-
calorimeter—a version of differential scanning calorimetry that
dance with internationally recognized principles on standard-
provides a sinusoidally varying temperature program to the test
ization established in the Decision on Principles for the
specimen in addition to the traditional isothermal or tempera-
Development of International Standards, Guides and Recom-
ture ramp programs. Results from analysis shall include
mendations issued by the World Trade Organization Technical
apparent and specific heat capacity.
Barriers to Trade (TBT) Committee.
4. Summary of Test Method
2. Referenced Documents
4.1 The heat capacity of a test specimen may be determined
2.1 ASTM Standards:
using the modulated temperature approach in which an oscil-
E473 Terminology Relating to Thermal Analysis and Rhe-
latory or periodically repeating temperature program (around
ology
an average temperature) is imposed upon a test specimen
E967 Test Method for Temperature Calibration of Differen-
producing an oscillatory (periodic) heat flow into or out of the
tial Scanning Calorimeters and Differential Thermal Ana-
specimen. The heat capacity of the test specimen may be
lyzers
obtained from the amplitude of the resultant heat flow divided
E968 Practice for Heat Flow Calibration of Differential
by the amplitude of the oscillatory (periodic) temperature that
produces it. Specific heat capacity is obtained by normalizing
the heat capacity to specimen mass.
This test method is under the jurisdiction of Committee E37 on Thermal
4.1.1 The accuracy of the heat capacity thus obtained
Measurements and is the direct responsibility of Subcommittee E37.10 on
depends upon experimental conditions. When a thin test
Fundamental, Statistical and Mechanical Properties.
Current edition approved June 1, 2023. Published June 2023. Originally
specimen encapsulated in a specimen pan of high thermal
approved in 1998. Last previous edition approved in 2017 as E1952 – 17. DOI:
conductivity is treated with temperature oscillations of long
10.1520/E1952-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1952 − 23
period (low frequency), the test specimen is assumed to environment of inert nitrogen purge gas at a rate of
achieve a uniform temperature distribution and the resultant 50 mL ⁄min 6 10 mL ⁄min.
heat capacity information will be comparable with those of
7.1.2 A Temperature Controller, capable of executing a
other non-oscillatory test methods.
specific temperature program by (1) operating the furnace
4.1.2 When one end of a thick test specimen is exposed to
between selected temperature limits at a rate of temperature
the temperature oscillations of short period (high frequency),
change of 1 °C ⁄min, (2) holding at an isothermal temperature
the test specimen will achieve a temperature distribution over
over the temperature range of 0 °C to 90 °C within 60.1 °C,
its length related to its thermal diffusivity.
and (3) sinusoidal varying temperature with an amplitude of
4.1.3 The apparent heat capacity information thus obtained
60.2 °C to 0.7 °C and a period of 60 s to 100 s (frequency of
is lower than that of the uniform temperature distribution case
10 mHz to 16 mHz).
described above and is proportional to the square root of
4 NOTE 1—The upper thermal conductivity achievable by this method is
thermal conductivity of the test specimens (1). The thermal
extended to 4 W (K·m) for instruments capable of 20 s periods (frequency
conductivity of the test specimen may be derived from the
of 50 mHz) (2).
apparent heat capacity of a thick specimen, the actual heat
7.1.3 A Calculating Device, capable of transforming the
capacity of a thin specimen, and a series of geometric and
experimentally determined modulated temperature and modu-
experimental constants.
lated specimen heat flow signals into the required continuous
4.2 If the thermal conductivity of the test specimen is low,
output forms of heat capacity (preferably in units of mJ/K),
approaching that of the purge gas surrounding it, a correction
specific heat capacity (preferably in units of J/(g·K)), and
to the measured thermal conductivity is required to compensate
average test temperature to the required accuracy and preci-
for heat losses from the thick test specimen.
sion.
4.3 Thermal diffusivity is derived from the determined 7.1.4 A Data Collecting Device, to provide a means of
thermal conductivity, specific heat capacity, and density of the
acquiring, storing, and displaying measured or calculated
test specimen. signals, or both. The minimum output signals required are heat
flow, temperature, time, heat capacity, specific heat capacity,
5. Significance and Use
and average temperature with a sensitivity of 0.001 mJ ⁄K for
heat capacity, 0.001 J ⁄(g·K) for specific heat capacity, 0.01 °C
5.1 Thermal conductivity is a useful design parameter for
for average temperature, and 0.1 min for time.
the rate of heat transfer through a material.
7.1.5 A Coolant System, to provide oscillatory heating and
5.2 The results of this test method may be used for design
cooling rates of at least 3 °C ⁄min.
purposes, service evaluation, manufacturing control, research
7.1.6 Inert Nitrogen, or other low conductivity purge gas
and development, and hazard evaluation. (See Practice E1231.)
flowing at a rate of 50 mL ⁄min (see 7.1.1).
6. Interferences
NOTE 2—Helium, a commonly used purge gas, is unacceptable for this
purpose, due to its very high thermal conductivity which results in reduced
6.1 Because the specimen size used in thermal analysis is on
range, precision, and accuracy.
the order of 10 mg to 100 mg, care must be taken to ensure it
7.2 A Balance, with a range of at least 200 mg to weigh
is homogeneous or representative of the material, or both.
specimens or containers, or both, (pans, crucibles, etc.) to
6.2 The calculation of thermal conductivity requires knowl-
60.01 mg.
edge of this specimen geometry. This test method requires a
specific specimen size and shape. Other geometries may be
7.3 Calipers or other length-measuring device with a range
used with the appropriate modifications to the calculating
greater than 4 mm, readable to 0.01 mm.
equations.
7.4 Sapphire Disk Calibration Material, 20 mg to 30 mg.
7. Apparatus
7.5 Polystyrene Thermal Conductivity Calibration Material,
of known thermal conductivity and specific heat capacity, in
7.1 A modulated temperature differential scanning calorim-
the shape of a right circular cylinder, 6.3 mm 6 0.2 mm in
eter consisting of:
diameter and 3.5 mm 6 0.3 mm thickness.
7.1.1 A Differential Scanning Calorimetry (DSC) Test
7.5.1 Polystyrene Specific Heat Capacity Reference
Chamber, of (1) a furnace to provide uniform controlled
Material, composed of the same material as the thermal
heating/cooling of a specimen and reference to a constant
conductivity calibration material, in the shape of a right
temperature or at a constant rate within the applicable range of
circular cylinder or disk, 6.3 mm 6 0.2 mm in diameter and
this test method; (2) a temperature sensor (or other signal
0.4 mm 6 0.1 mm in thickness.
source) to provide an indication of the specimen temperature
readable to 0.01 °C; (3) a differential sensor to detect a heat
7.6 Circular Aluminum Disk, 6.3 mm in diameter and
flow difference between the specimen and reference equivalent
0.01 mm or thinner in thickness.
to 0.001 mW; and (4) a means of sustaining a test temperature
7.7 Containers (pans, crucibles, etc.) that are inert to the
specimen and are of suitable structural shape and integrity to
contain the specimen in accordance with the specific require-
The boldface numbers in parentheses refer to a list of references at the end of
this standard. ments of this test method.
E1952 − 23
7.8 Silicone Heat Transfer Fluid, with no thermal transi- 10.3 Determine the thermal conductivity calibration factor,
tions over the temperature range from –10 °C to 100 °C. D.
10.3.1 Weigh the thin (0.4 mm) polystyrene (or other)
NOTE 3—Silicone oil with a viscosity of about 1 Pa·s (10 poise) has
calibration disk (from 7.5.1); record the mass as m1. Enter it as
been found satisfactory for this application.
an experimental parameter into the apparatus calculator. En-
7.9 While not required, users may find the following op-
capsulate the thin polystyrene calibration disk in a standard
tional apparatus and materials useful for this determination.
aluminum sample container with lid.
7.9.1 Polymeric Thermal Conductivity Performance
10.3.2 Place the encapsulated test specimen in the DSC on
Material, a right circular cylinder, 6.3 mm 6 0.2 mm in diam-
the specimen sensor. Use an empty aluminum container and lid
eter and 3.5 mm 6 0.3 mm in length.
on the reference side.
7.9.2 Polymeric Specific Heat Capacity Reference Material,
composed of the same material as the thermal conductivity
NOTE 5—Matching the combined weights of the reference container
standard reference material, a right circular cylinder or disk,
and lid to those of the specimen container and lid within 60.1 mg
produces the best results.
6.3 mm 6 0.2 mm in diameter and 0.4 mm 6 0.1 mm in thick-
ness.
10.3.3 Measure the heat capacity of the thin polystyrene
calibration material using the conditions of 10.2.1. Record the
8. Sampling
specific heat capacity (c ) in units of J/(g·K).
p
8.1 Select two right circular cylinders, both nominally
NOTE 6—This value for the specific heat capacity of polystyrene may be
6.3 mm in diameter. The first of these test specimens is
compared against the literature values listed in Table 1 as a performance
nominally 0.4 mm thick and the second is nominally 3.5 mm
criteria test.
thick. These test specimens are most conveniently obtained by
cutting from 0.25-in. diameter rod, a common material form. 10.3.4 Weigh the thick (3.5 mm) polystyrene calibration
disk (from 7.5); record the mass as m2; and enter it into the
NOTE 4—Other fabrication techniques, such as cutting from sheet stock
experimental parameters screen on the measuring apparatus.
using cork borers, machining from stock, or molding may also be used.
10.3.5 Measure and record the diameter (d) and length (L)
8.1.1 Polish the circular end surfaces of the test specimens
of the polystyrene calibration test specimen.
smooth and parallel to within 630 μm with 600 grit emery
10.3.6 Moisten the DSC sample and reference sensors with
paper.
silicone oil. Place a thin aluminum disk over each sensor.
9. Calibration
Carefully place the thick sample (which has been moistened
with oil on the bottom side) on the aluminum disk covering the
9.1 Calibrate the temperature signal from the apparatus in
sample sensor.
accordance with Practice E967 using an indium reference
material and a heating rate of 1 °C ⁄min.
NOTE 7—Ensure that silicone oil does not change the characteristics of
the test specimen. It may leave a residue that must be cleaned before
9.2 Calibrate the heat flow signal from the apparatus in
alternative apparatus use. Xylene is a suitable solvent for cleaning.
accordance with Practice E968 using an indium reference
NOTE 8—A cotton swab may be wetted with silicon oil and the pressed
material.
between the fingers to remove any excess oil. The “moist” cotton swab
9.3 Calibrate the apparatus for heat capacity measurements may be passed once over the surface to “wet” it with the oil.
in accordance with the instructions of the manufacturer as
10.3.7 Measure the apparent heat capacity of the specimen
described in the instrument manual using isothermal tempera-
in accordance with the conditions of 10.2.1. Record the
ture conditions (at the mid-point of the temperature range of
apparent heat capacity (c) in the units of mJ/K.
interest), the sapphire calibration material (from 7.4) 60.5 °C
amplitude and 80 s period (12.5 mHz frequency).
10. Procedure
A
TABLE 1 Polystyrene Specific Heat Capacity
10.1 Measure thermal conductivity under quasi-isothermal
B
Temperature Specific Heat Capacity
conditions at an operator-selected temperature within the range
(°C) (K) (J/(g • K))
from 0 °C to 90 °C. If measurements at additional temperatures 6.8 280.0 1.1326
16.8 290.0 1.1775
are desired, repeat the procedure at those additional tempera-
26.8 300.0 1.2230
tures.
36.8 310.0 1.2691
46.8 320.0 1.3156
10.2 A common set of experimental conditions are used for
50.0 323.2 1.3305
each measurement:
56.8 330.0 1.3626
66.8 340.0 1.4100
10.2.1 Select the modulated mode on the DSC and record
76.8 350.0 1.4577
the heat capacity signal. Equilibrate the apparatus at the test
86.8 360.0 1.5056
temperature selected by the operator. Modulate the temperature
96.8 370.0 1.5539
with an amplitude of 60.5 °C and a period (P) of 80 s
A
Gaur, U.,
...

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: E1952 − 17 E1952 − 23
Standard Test Method for
Thermal Conductivity and Thermal Diffusivity by Modulated
Temperature Differential Scanning Calorimetry
This standard is issued under the fixed designation E1952; 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.
1. Scope*Scope
1.1 This test method describes the determination of thermal conductivity of homogeneous, non-porous solid materials in the range
of 0.10 W/(K • m)W/(K·m) to 1.0 W ⁄(K • m)⁄(K·m) by modulated temperature differential scanning calorimeter. This range
includes many polymeric, glass, and ceramic materials. Thermal diffusivity, which is related to thermal conductivity through
specific heat capacity and density, may also be derived. Thermal conductivity and diffusivity can be determined at one or more
temperatures over the range of 0°C to 90°C.0 °C to 90 °C.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to
inch-pound units that are provided for information only and are not considered standard.
1.3 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.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
E473 Terminology Relating to Thermal Analysis and Rheology
E967 Test Method for Temperature Calibration of Differential Scanning Calorimeters and Differential Thermal Analyzers
E968 Practice for Heat Flow Calibration of Differential Scanning Calorimeters (Withdrawn 2023)
E1142 Terminology Relating to Thermophysical Properties
E1231 Practice for Calculation of Hazard Potential Figures of Merit for Thermally Unstable Materials
E2161 Terminology Relating to Performance Validation in Thermal Analysis and Rheology
3. Terminology
3.1 Definitions:
3.1.1 Specific technical terms used in this test method are defined in Terminologies E473, E1142, and E2161 including calibration,
This test method is under the jurisdiction of Committee E37 on Thermal Measurements and is the direct responsibility of Subcommittee E37.10 on Fundamental,
Statistical and Mechanical Properties.
Current edition approved Sept. 1, 2017June 1, 2023. Published September 2017June 2023. Originally approved in 1998. Last previous edition approved in 20112017 as
E1952 – 11. DOI: 10.1520/E1952-17. – 17. DOI: 10.1520/E1952-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.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
E1952 − 23
differential scanning calorimetry, heat capacity, modulated temperature, precision, reference material, relative standard deviation,
repeatability, reproducibility, specific heat capacity, standard deviation, thermal analysis, thermal conductance, and thermal
conductivity.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 modulated temperature differential scanning calorimeter—a version of differential scanning calorimetry that provides a
sinusoidally varying temperature program to the test specimen in addition to the traditional isothermal or temperature ramp
programs. Results from analysis shall include apparent and specific heat capacity.
4. Summary of Test Method
4.1 The heat capacity of a test specimen may be determined using the modulated temperature approach in which an oscillatory
or periodically repeating temperature program (around an average temperature) is imposed upon a test specimen producing an
oscillatory (periodic) heat flow into or out of the specimen. The heat capacity of the test specimen may be obtained from the
amplitude of the resultant heat flow divided by the amplitude of the oscillatory (periodic) temperature that produces it. Specific
heat capacity is obtained by normalizing the heat capacity to specimen mass.
4.1.1 The accuracy of the heat capacity thus obtained depends upon experimental conditions. When a thin test specimen
encapsulated in a specimen pan of high thermal conductivity is treated with temperature oscillations of long period (low
frequency), the test specimen is assumed to achieve a uniform temperature distribution and the resultant heat capacity information
will be comparable with those of other non-oscillatory test methods.
4.1.2 When one end of a thick test specimen is exposed to the temperature oscillations of short period (high frequency), the test
specimen will achieve a temperature distribution over its length related to its thermal diffusivity.
4.1.3 The apparent heat capacity information thus obtained is lower than that of the uniform temperature distribution case
described above and is proportional to the square root of thermal conductivity of the test specimens (1). The thermal conductivity
of the test specimen may be derived from the apparent heat capacity of a thick specimen, the actual heat capacity of a thin
specimen, and a series of geometric and experimental constants.
4.2 If the thermal conductivity of the test specimen is low, approaching that of the purge gas surrounding it, a correction to the
measured thermal conductivity is required to compensate for heat losses from the thick test specimen.
4.3 Thermal diffusivity is derived from the determined thermal conductivity, specific heat capacity, and density of the test
specimen.
5. Significance and Use
5.1 Thermal conductivity is a useful design parameter for the rate of heat transfer through a material.
5.2 The results of this test method may be used for design purposes, service evaluation, manufacturing control, research and
development, and hazard evaluation. (See Practice E1231.)
6. Interferences
6.1 Because the specimen size used in thermal analysis is on the order of 10 mg to 100 mg, care must be taken to ensure it is
homogeneous or representative of the material, or both.
6.2 The calculation of thermal conductivity requires knowledge of this specimen geometry. This test method requires a specific
specimen size and shape. Other geometries may be used with the appropriate modifications to the calculating equations.
7. Apparatus
7.1 A modulated temperature differential scanning calorimeter consisting of:
The boldface numbers in parentheses refer to a list of references at the end of this standard.
E1952 − 23
7.1.1 A Differential Scanning Calorimetry (DSC)(DSC) Test Chamber, of (1) a furnace to provide uniform controlled
heating/cooling of a specimen and reference to a constant temperature or at a constant rate within the applicable range of this test
method; (2) a temperature sensor (or other signal source) to provide an indication of the specimen temperature readable to
0.01°C;0.01 °C; (3) a differential sensor to detect a heat flow difference between the specimen and reference equivalent to
0.001 mW; and (4) a means of sustaining a test temperature environment of inert nitrogen purge gas at a rate of
50 mL ⁄min 6 10 mL ⁄min.
7.1.2 A Temperature Controller, capable of executing a specific temperature program by (1) operating the furnace between
selected temperature limits at a rate of temperature change of 1°C/min,1 °C ⁄min, (2) holding at an isothermal temperature over the
temperature range of 0°C to 90°C within 60.1°C,0 °C to 90 °C within 60.1 °C, and (3) sinusoidal varying temperature with an
amplitude of 60.2°C to 0.7°C60.2 °C to 0.7 °C and a period of 60 s to 100 s (frequency of 10 mHz to 16 mHz).
NOTE 1—The upper thermal conductivity achievable by this method is extended to 4 W (K • m)(K·m) for instruments capable of 20 s periods (frequency
of 50 mHz) (2).
7.1.3 A Calculating Device, capable of transforming the experimentally determined modulated temperature and modulated
specimen heat flow signals into the required continuous output forms of heat capacity (preferably in units of mJ/K), specific heat
capacity (preferably in units of J/(g • K)), J/(g·K)), and average test temperature to the required accuracy and precision.
7.1.4 A Data Collecting Device, to provide a means of acquiring, storing, and displaying measured or calculated signals, or both.
The minimum output signals required are heat flow, temperature, time, heat capacity, specific heat capacity, and average
temperature with a sensitivity of 0.001 mJ ⁄K for heat capacity, 0.001 J ⁄(g • K)⁄(g·K) for specific heat capacity, 0.01°C0.01 °C for
average temperature, and 0.1 min for time.
7.1.5 A Coolant System, to provide oscillatory heating and cooling rates of at least 3°C/min.3 °C ⁄min.
7.1.6 Inert Nitrogen, or other low conductivity purge gas flowing at a rate of 50 mL ⁄min (see 7.1.1).
NOTE 2—Helium, a commonly used purge gas, is unacceptable for this purpose, due to its very high thermal conductivity which results in reduced range,
precision, and accuracy.
7.2 A Balance, with a range of at least 200 mg to weigh specimens or containers, or both, (pans, crucibles, etc.) to 60.01 mg.
7.3 Calipers or other length-measuring device with a range greater than 4 mm, readable to 0.01 mm.
7.4 Sapphire Disk Calibration Material, 20 mg to 30 mg.
7.5 Polystyrene Thermal Conductivity Calibration Material, of known thermal conductivity and specific heat capacity, in the
shape of a right circular cylinder, 6.3 6 0.2 mm6.3 mm 6 0.2 mm in diameter and 3.5 6 0.3 mm3.5 mm 6 0.3 mm thickness.
7.5.1 Polystyrene Specific Heat Capacity Reference Material, composed of the same material as the thermal conductivity
calibration material, in the shape of a right circular cylinder or disk, 6.3 6 0.2 mm6.3 mm 6 0.2 mm in diameter and
0.4 6 0.1 mm0.4 mm 6 0.1 mm in thickness.
7.6 Circular Aluminum Disk, 6.3 mm in diameter and 0.01 mm or thinner in thickness.
7.7 Containers (pans, crucibles, etc.) that are inert to the specimen and are of suitable structural shape and integrity to contain the
specimen in accordance with the specific requirements of this test method.
7.8 Silicone Heat Transfer Fluid, with no thermal transitions over the temperature range from –10°C to 100°C.–10 °C to 100 °C.
NOTE 3—Silicone oil with a viscosity of about 1 Pa • s1 Pa·s (10 poise) has been found satisfactory for this application.
7.9 While not required, users may find the following optional apparatus and materials useful for this determination.
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7.9.1 Polymeric Thermal Conductivity Performance Material, a right circular cylinder, 6.3 6 0.2 mm6.3 mm 6 0.2 mm in
diameter and 3.5 6 0.3 mm3.5 mm 6 0.3 mm in length.
7.9.2 Polymeric Specific Heat Capacity Reference Material, composed of the same material as the thermal conductivity standard
reference material, a right circular cylinder or disk, 6.3 6 0.26.3 mm 6 0.2 mm in diameter and 0.4 6 0.1 mm0.4 mm 6 0.1 mm
in thickness.
8. Sampling
8.1 Select two right circular cylinders, both nominally 6.3 mm in diameter. The first of these test specimens is nominally 0.4 mm
thick and the second is nominally 3.5 mm thick. These test specimens are most conveniently obtained by cutting from 0.25-in.
diameter rod, a common material form.
NOTE 4—Other fabrication techniques, such as cutting from sheet stock using cork borers, machining from stock, or molding may also be used.
8.1.1 Polish the circular end surfaces of the test specimens smooth and parallel to within 630 μm with 600 grit emery paper.
9. Calibration
9.1 Calibrate the temperature signal from the apparatus in accordance with Practice E967 using an indium reference material and
a heating rate of 1°C/min.1 °C ⁄min.
9.2 Calibrate the heat flow signal from the apparatus in accordance with Practice E968 using an indium reference material.
9.3 Calibrate the apparatus for heat capacity measurements in accordance with the instructions of the manufacturer as described
in the instrument manual using isothermal temperature conditions (at the mid-point of the temperature range of interest), the
sapphire calibration material (from 7.4) 60.5°C60.5 °C amplitude and 80 s period (12.5 mHz frequency).
10. Procedure
10.1 Measure thermal conductivity under quasi-isothermal conditions at an operator-selected temperature within the range from
0°C to 90°C.0 °C to 90 °C. If measurements at additional temperatures are desired, repeat the procedure at those additional
temperatures.
10.2 A common set of experimental conditions are used for each measurement:
10.2.1 Select the modulated mode on the DSC and record the heat capacity signal. Equilibrate the apparatus at the test temperature
selected by the operator. Modulate the temperature with an amplitude of 60.5°C60.5 °C and a period (P) of 80 s (12.5 mHz). (See
Note 5.) After 15 min equilibration time, record the average test temperature (T) and the specific heat capacity (c ) or apparent heat
p
capacity (c) as called for in the appropriate section.
10.3 Determine the thermal conductivity calibration factor, D.
10.3.1 Weigh the thin (0.4 mm) polystyrene (or other) calibration disk (from 7.5.1); record the mass as m.m1. Enter it as an
experimental parameter into the apparatus calculator. Encapsulate the thin polystyrene calibration disk in a standard aluminum
sample container with lid.
10.3.2 Place the encapsulated test specimen in the DSC on the specimen sensor. Use an empty aluminum container and lid on the
reference side.
NOTE 5—Matching the combined weights of the reference container and lid to those of the specimen container and lid within 60.1 mg produces the best
results.
10.3.3 Measure the heat capacity of the thin polystyrene calibration material using the conditions of 10.2.1. Record the specific
heat capacity (c ) in units of J/(g • K).J/(g·K).
p
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NOTE 6—This value for the specific heat capacity of polystyrene may be compared against the literature values listed in Table 1 as a performance criteria
test.
10.3.4 Weigh the thick (3.5 mm) polystyrene calibration disk (from 7.5); record the mass as m;2; and enter it into the experimental
parameters screen on the measuring apparatus.
10.3.5 Measure and record the diameter (d) and length (L) of the polystyrene calibration test specimen.
10.3.6 Moisten the DSC sample and reference sensors with silicone oil. Place a thin aluminum disk over each sensor. Carefully
place the thick sample (which has been moistened with oil on the bottom side) on the aluminum disk covering the sample sensor.
NOTE 7—Ensure that silicone oil does not change the characteristics of the test specimen. It may leave a residue that must be cleaned before alternative
apparatus use. Xylene is a suitable solvent for cleaning.
NOTE 8—A cotton swab may be wetted with silicon oil and the pressed between the fingers to remove any excess oil. The “moist” cotton swab may be
passed once over the surface to “wet” it with the oil.
10.3.7 Measure the apparent heat capacity of the specimen in accordance with the conditions of 10.2.1. Record the apparent heat
capacity (c) in the units of mJ/K.
10.3.8 Using the values of P (from 10.2.1), c (from 10.3.3); and m,L, and d (from 10.3.4 and 10.3.5), calculate the observed
p
thermal conductivity (λ ) for polystyrene using Eq 1 (see 11.1).
o
NOTE 9—An example calculation is presented in 11.5.1.
10.3.9 Determine the value for thermal conductivity of polystyrene (λ ) for the corresponding temperature (T) (from 10.2.1) from
r
Table 2, linearly interpolating between values if necessary.
10.3.10 Using the values for λ from 10.3
...