ASTM E2347-21

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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: E2347 − 16 E2347 − 21
Standard Test Method for
Indentation Softening Temperature by Thermomechanical
Analysis
This standard is issued under the fixed designation E2347; 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
1.1 This test method is applicable to high modulus materials that soften upon heating to a modulus less than 6.0 MPa. This test
method describes the determination of the temperature at which the specific modulus of either 6.65 MPa (Method A) or 33.3 MPa
(Method B) (equivalent to Test Method D1525) of a test specimen is realized by indentation measurement using a
thermomechanical analyzer as the test specimen is heated. This temperature is identified as the indentation softening temperature.
The test may be performed over the temperature range of ambient to 300°C.300 °C.
NOTE 1—This test method is intended to provide results similar to those of Test Method D1525 but is performed on a thermomechanical analyzer using
a smaller diameter indenting probe. Equivalence of results to those obtained by Test Method D1525 has been demonstrated on a limited number of
materials. Until the user demonstrates equivalence, the results of this Test Method shall be considered to be independent and unrelated to those of Test
Method D1525.
1.2 This test method is not recommended for ethyl cellulose, poly (vinyl chloride), poly (vinylidene chloride) and other materials
having a large measurement imprecision (see Test Method D1525 and 5.3 and Section 14).
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 There is no ISO standard equivalent to this test method.
1.4 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.
1.5 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:
D1525 Test Method for Vicat Softening Temperature of Plastics
E473 Terminology Relating to Thermal Analysis and Rheology
This test method is under the jurisdiction of ASTM Committee E37 on Thermal Measurements and is the direct responsibility of Subcommittee E37.10 on Fundamental,
Statistical and Mechanical Properties.
Current edition approved April 1, 2016July 1, 2021. Published April 2016July 2021. Originally approved in 2004. Last previous edition approved in 20112016 as E2347
– 11.16. DOI: 10.1520/E2347-16.10.1520/E2347-21.
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 standardsstandard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2347 − 21
E1142 Terminology Relating to Thermophysical Properties
E1363 Test Method for Temperature Calibration of Thermomechanical Analyzers
E2113 Test Method for Length Change Calibration of Thermomechanical Analyzers
E2206 Test Method for Force Calibration of Thermomechanical Analyzers
3. Terminology
3.1 Definitions:
3.1.1 Specific technical terms used in this test method are defined in Terminologies E473 and E1142 including Celsius, complex
modulus, modulus, strain, stress, storage modulus, thermal analysis, and thermomechanical analysis.
3.1.2 penetration softening temperature, [°C],n—the temperature at which a test specimen has a modulus of either 6.65 MPa or
33.3 MPa as measured in penetration.
4. Summary of Test Method
4.1 The modulus of a material may be determined by the indentation (penetration) of a circular, flat tipped probe. The relationship
between modulus of a material (stress divided by strain) and penetration depth is given by:
E 5 3 F/~4 D d! (1)
where:
E = modulus, MPa,
F = force, N,
D = diameter of a circular, flat tipped probe, mm, and
d = penetration depth, mm.
NOTE 2—Note the identity Pa = N / m .
4.2 Some materials soften upon heating. For such materials, the modulus may be determined by penetration as the sample is
heated. This test method identifies the temperature at which the modulus of the specimen is determined to be 6.65 MPa (Method
A) or 33.3 MPa (Method B).
4.3 Specifically, a test specimen is tested in penetration using a circular, flat tipped probe. A known stress is applied to the center
of a test specimen as it is heated at a constant rate from ambient temperature to the upper temperature limit for the material. The
penetration (that is, deflection) of the test specimen is recorded as a function of temperature. The temperature at which the modulus
of the specimen is determined to be 6.65 MPa (Method A) or 33.3 MPa (Method B) is determined to be the penetration softening
temperature.
5. Significance and Use
5.1 Data obtained by this test method shall not be used to predict the behavior of materials at elevated temperatures except in
applications in which the conditions of time, temperature, method of loading, and stress are similar to those specified in the test.
5.2 This test method is particularly suited for quality control and development work. The data are not intended for use in design
or predicting endurance at elevated temperatures.
5.3 Ruggedness testing indicates that some materials, such as poly (vinyl chloride) exhibit substantially greater imprecision than
that described in Section 14 for “well behaved” materials.
6. Apparatus
6.1 A thermomechanical analyzer consisting of:
-1 -1
6.1.1 Rigid Specimen Holder, of inert, low expansivity material (<1 μm m °C ) to center the specimen in the furnace and to fix
the specimen to mechanical ground.
-1 -1
6.1.2 Rigid Penetration Probe, of inert, low expansivity material (<1 μm m °C ) that contacts the specimen with an applied
E2347 − 21
compression force (see Fig. 1). The tip shall be 0.1 mm to 1.0 mm in diameter, free of burrs and be perpendicular to the axis of
the probe. The tip shall protrude at least 0.1 mm from the end of the probe.>
6.1.3 Deflection Sensing Element, having a linear output over a minimum range of 5 mm to measure the displacement of the rigid
penetration probe (see 6.1.2) readable to within 60.1 μm.
6.1.4 Programmable Force Transducer, to generate a constant force (62.5 %) between 0.05 N and 1.0 N that is applied to the
specimen through the rigid penetration probe (see 6.1.2).
NOTE 3—Other forces may be used but shall be reported.
6.1.5 Temperature Sensor, that can be positioned reproducibly in close proximity to the specimen to measure its temperature over
the range of 25 to 300°C to 6 0.1°C.°C to 300 °C readable to 60.1 °C.
6.1.6 Temperature Programmer and Furnace, capable of temperature programming the test specimen from ambient to 300°C 300
°C at a linear rate of at least 2.0 °C 6 0.2°C/min.0.2 °C/min.
6.1.7 Means of Providing a Specimen Environment, of inert gas at a purge rate of 50 mL/min 6 5 %.
NOTE 4—Typically, inert purge gas that inhibits specimen oxidation are 99.9+ % pure nitrogen, helium or argon. Dry gases are recommended for all
experiments unless the effect of moisture is part of the study.
6.1.8 Data Collection Device, to provide a means of acquiring, storing, and displaying measured or calculated signals, or both.
The minimum output signals required are a change in linear dimension to a sensitivity of readable to 60.1 mm, and temperature
to a sensitivity of readable to 61 μm.
6.1.9 Calipers, Micrometer,Micrometre, or other length measuring device capable of a length measurement of up to 2 mm with
a precision of readable to 61 μm.
7. Hazards
7.1 Toxic or corrosive effluents, or both, may be released when heating some materials and could be harmful to personnel and to
apparatus.
FIG. 1 Penetration Probe
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8. Sampling, Test Specimens, and Test Units
8.1 Because the specimen size is small, care shall be taken to ensure that each specimen is homogeneous and representative of
the sample as a whole.
8.2 The specimen may be cut from sheets, plates or molded shapes, or may be molded to the desired finished dimensions.
8.3 A typical test specimen is a rectangle 7 mm to 8 mm × 7 mm to 8 mm or a circle 7 mm to 8 mm in diameter with a thickness
of 1 mm to 3 mm.
8.4 This test method assumes that the material is isotropic. Should specimens be anisotropic, such as in reinforced composites,
the direction of the reinforcing agent shall be reported relative to the compression (specimen) dimensions.
9. Preparation of Apparatus
9.1 Perform any setup or calibration procedures recommended by the apparatus manufacturer in the operations manual.
10. Calibration and Standardization
10.1 Calibrate the temperatu
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