ASTM E2008-17(2021)
(Test Method)Standard Test Methods for Volatility Rate by Thermogravimetry
Standard Test Methods for Volatility Rate by Thermogravimetry
SIGNIFICANCE AND USE
5.1 Volatility of a material is not an equilibrium thermodynamic property but is a characteristic of a material related to a thermodynamic property that is vapor pressure. It is influenced by such factors as surface area, temperature, particle size, and purge gas flow rate; that is, it is diffusion controlled.
5.2 The extent of containment achieved for specimens in these test methods by means of a pinhole opening between 0.33 mm to 0.38 mm allows for measurement circumstances that are relatively insensitive to experimental variables other than temperature. Decreasing the extent of containment by use of pinholes larger than 0.38 mm will increase the magnitude of the observed rate of mass loss but will also reduce the measurement precision by increasing the sensitivity to variations in other experimental variables.
5.3 Results obtained by these test methods are not strictly equivalent to those experienced in processing or handling conditions but may be used to rank materials for their volatility in such circumstances. Therefore, the volatility rates determined by these test methods should be considered as index values only.
5.4 The volatility rate may be used to estimate such quantifiable values as drying interval or the extent of volatile release from a process.
SCOPE
1.1 These test methods cover procedures for assessing the volatility of solids and liquids at given temperatures using thermogravimetry under prescribed experimental conditions. Results of these test methods are obtained as volatility rates expressed as mass per unit time. Rates ≥5 μg/min are achievable with these test methods.
1.2 Temperatures typical for these test methods are within the range from 25 °C to 500 °C. This temperature range may differ depending upon the instrumentation used.
1.3 These test methods are intended to provide a value for the volatility rate of a sample using a thermogravimetric analysis measurement on a single representative specimen. It is the responsibility of the user of these test methods to determine the need for and the number of repetitive measurements on fresh specimens necessary to satisfy end use requirements.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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.
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
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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: E2008 − 17 (Reapproved 2021)
Standard Test Methods for
Volatility Rate by Thermogravimetry
This standard is issued under the fixed designation E2008; 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 2. Referenced Documents
1.1 These test methods cover procedures for assessing the 2.1 ASTM Standards:
volatility of solids and liquids at given temperatures using E177 Practice for Use of the Terms Precision and Bias in
thermogravimetry under prescribed experimental conditions. ASTM Test Methods
Results of these test methods are obtained as volatility rates E473 Terminology Relating to Thermal Analysis and Rhe-
expressed as mass per unit time. Rates ≥5 µg/min are achiev- ology
able with these test methods. E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.2 Temperatures typical for these test methods are within
E1142 Terminology Relating to Thermophysical Properties
the range from 25 °C to 500 °C. This temperature range may
E1582 Test Method for Temperature Calibration of Thermo-
differ depending upon the instrumentation used.
gravimetric Analyzers
1.3 These test methods are intended to provide a value for
E1860 Test Method for Elapsed Time Calibration of Ther-
the volatility rate of a sample using a thermogravimetric
mal Analyzers
analysismeasurementonasinglerepresentativespecimen.Itis
E2040 Test Method for Mass Scale Calibration of Thermo-
theresponsibilityoftheuserofthesetestmethodstodetermine
gravimetric Analyzers
the need for and the number of repetitive measurements on
fresh specimens necessary to satisfy end use requirements.
3. Terminology
1.4 The values stated in SI units are to be regarded as
3.1 Definitions:
standard. No other units of measurement are included in this
3.1.1 The following terms are applicable to these test
standard.
methods and can be found in Terminologies E473 and E1142:
3.1.1.1 thermogravimetric analysis (TGA),
1.5 This standard does not purport to address all of the
3.1.1.2 thermogravimetry (TG), and
safety concerns, if any, associated with its use. It is the
3.1.1.3 volatility.
responsibility of the user of this standard to establish appro-
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 volatility rate—the rate of conversion of a solid or
1.6 This international standard was developed in accor-
liquid substance into the vapor state at a given temperature;
dance with internationally recognized principles on standard-
mass per unit time.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4. Summary of Test Method
mendations issued by the World Trade Organization Technical
4.1 Asolid or liquid specimen is confined in an appropriate
Barriers to Trade (TBT) Committee.
container with a pinhole opening between 0.33 mm and 0.38
mm. The confined specimen is heated within a thermogravi-
metricanalyzereithertoatemperatureandheldconstantatthat
temperature for a fixed interval of time (Test MethodA, Fig. 1)
or at a slow constant heating rate between temperature limits
(TestMethodB,Fig.2).Themassofthespecimenismeasured
continuously and it or its rate of change is displayed as a
function of time or temperature. The volatility rate at any
These test methods are under the jurisdiction of ASTM Committee E37 on
ThermalMeasurementsandarethedirectresponsibilityofSubcommitteeE37.01on
Calorimetry and Mass Loss. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
CurrenteditionapprovedJuly1,2021.PublishedJuly2021.Originallyapproved contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
in 1999. Last previous edition approved in 2017 as E2008 – 17. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
E2008-17R21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2008 − 17 (2021)
FIG. 1 Test Method A: R = Average Volatility Rate
v
temperature is reported either as the average rate of mass loss 6. Interferences
per unit time from Test Method A or as the instantaneous rate
6.1 Specimens that consist of a mixture of two or more
of mass loss (first derivative) per unit time from Test Method
volatile components or that undergo decomposition during this
B.
test may exhibit curvature in the mass loss versus time plot of
Test Method A (see Fig. 3). In such cases the volatility rate is
5. Significance and Use
not constant and shall not be reported as a singular value.
5.1 Volatility of a material is not an equilibrium thermody-
namic property but is a characteristic of a material related to a
7. Apparatus
thermodynamic property that is vapor pressure. It is influenced
7.1 The essential instrumentation required to provide the
by such factors as surface area, temperature, particle size, and
minimumthermogravimetricanalyticalcapabilityforthesetest
purge gas flow rate; that is, it is diffusion controlled.
methods includes:
5.2 The extent of containment achieved for specimens in
7.1.1 A Thermobalance, composed of:
thesetestmethodsbymeansofapinholeopeningbetween0.33
7.1.1.1 AFurnace, to provide uniform controlled heating of
mmto0.38mmallowsformeasurementcircumstancesthatare
a specimen at a constant temperature or at a constant rate
relatively insensitive to experimental variables other than
within the applicable temperature range of these test methods;
temperature. Decreasing the extent of containment by use of
7.1.1.2 A Temperature Sensor, to provide an indication of
pinholes larger than 0.38 mm will increase the magnitude of
the specimen/furnace temperature to 61K;
the observed rate of mass loss but will also reduce the
7.1.1.3 A continuously recording Balance, to measure the
measurement precision by increasing the sensitivity to varia-
specimen mass with a minimum capacity of 100 mg and a
tions in other experimental variables.
sensitivity of 610 µg;
5.3 Results obtained by these test methods are not strictly
7.1.1.4 Ameans of sustaining the specimen/container under
equivalent to those experienced in processing or handling
atmospheric control of inert gas (nitrogen, helium, and so
conditionsbutmaybeusedtorankmaterialsfortheirvolatility
forth) of 99.9 % purity at a purge rate of 50 mL/min to 100
in such circumstances. Therefore, the volatility rates deter-
mL/min 65%.
mined by these test methods should be considered as index
7.1.2 A Temperature Controller, capable of executing a
values only.
specifictemperatureprogrambyoperatingthefurnacebetween
5.4 The volatility rate may be used to estimate such quan- selected temperature limits at a rate of temperature change of
tifiablevaluesasdryingintervalortheextentofvolatilerelease 1 K/min to 2 K/min constant to within 60.1 K/min or to
from a process. rapidly heat a specimen at a minimum of 50 K/min to an
E2008 − 17 (2021)
FIG. 2 Test Method B: R = Instantaneous Volatility Rate
v
FIG. 3 Test Method A—Two Component Mixture
isothermal temperature that is maintained constant to 61 K for signals, or both. The minimum output signals required for
a minimum of 30 min. thermogravimetry are mass, temperature, and time.
7.1.3 A Data Collection Device, to provide a means of 7.1.4 Sealable Containers, (pans, crucibles, and so forth),
acquiring, storing, and displaying measured or calculated that are inert to the specimen, that will remain gravimetrically
E2008 − 17 (2021)
stable within the temperature limits of these test methods, and 30 mg are typical for this test method, with the larger mass
that contain a pinhole in the lid of diameter between 0.33 mm being used for more volatile specimens. (Warning—Volatile
and 0.38 mm. materials may pose a respiratory hazard. Avoid unnecessary
exposure to vapors.)
NOTE 1—The most critical parameters for containers suitable for use
10.1.4 Place the encapsulated specimen in the thermogravi-
with these test methods are the pinhole diameter and the lid thickness.
metric analyzer, close the furnace, and allow the temperature,
Sealable containers of volumes (25 µLto 50 µL) and wall thicknesses (80
µmto150µm)commerciallyavailablefromMettler-Toledo,PerkinElmer
purge, and so forth, to become stable within 61 % of settings.
Corporation, and TA Instruments, Inc., have been found suitable for this
NOTE 3—For highly volatile substances, a significant mass fraction of
purpose.
the specimen could be lost during this period of equilibration. Any large
7.2 Auxiliary equipment necessary or useful in conducting
discrepancy between the specimen mass as delivered and subsequently
these test methods includes:
recorded by the thermobalance should be noted in the report.
7.2.1 While not required, it is convenient to have a data
10.1.5 Heat the specimen rapidly at 50 K/min to the desired
analysis device that will continuously calculate and display the
isothermal temperature, and thereafter, maintain the isothermal
first derivative of mass with respect to time (in mass/min)
temperature to 61 K for 30 min. Record the specimen mass in
capable of detecting 0.05 µg/min.
mg or µg continually during this heating program versus time.
7.2.2 Device to encapsulate the specimen in sealable con-
The specimen temperature should be recorded during the
tainers.
heating program.
7.2.3 Micropipette or syringe to deliver liquid specimens of
NOTE 4—If the specimen is exhausted before 30 min have elapsed, it is
1 µL to 30 µL into the containers.
recommended that the test be repeated with a larger specimen mass. If
excessively large specimen mass is required to complete a 30-min test
8. Sampling
time, a
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