ASTM E1131-20

Standard Test Method for Compositional Analysis by Thermogravimetry

SIGNIFICANCE AND USE
5.1 This test method is intended for use in quality control, material screening, and related problem solving where a compositional analysis is desired or a comparison can be made with a known material of the same type.  
5.2 The parameters described should be considered as guidelines. They may be altered to suit a particular analysis, provided the changes are noted in the report.  
5.3 The proportion of the determined components in a given mixture or blend may indicate specific quality or end use performance characteristics. Particular examples include the following:  
5.3.1 Increasing soot (carbon) content of used diesel lubricating oils indicates decreasing effectiveness.  
5.3.2 Specific carbon-to-polymer ratio ranges are required in some elastomeric and plastic parts in order to achieve desired mechanical strength and stability.  
5.3.3 Some filled elastomeric and plastic products require specific inert content (for example, ash, filler, reinforcing agent, etc.) to meet performance specifications.  
5.3.4 The volatile matter, fixed carbon, and ash content of coal and coke are important parameters. The “ranking” of coal increases with increasing carbon content and decreasing volatile and hydrocarbon, (medium volatility) content.
SCOPE
1.1 This test method provides a general technique incorporating thermogravimetry to determine the amount of highly volatile matter, medium volatile matter, combustible material, and ash content of compounds. This test method will be useful in performing a compositional analysis in cases where agreed upon by interested parties.  
1.2 This test method is applicable to solids and liquids.  
1.3 The temperature range of test is typically room temperature to 1000 °C. Composition between 1 weight % and 100 weight % of individual components may be determined.  
1.4 This test method utilizes an inert and reactive gas environment.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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.  
1.7 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: 14-Mar-2020
• ICS: 71.040.40 - Chemical analysis
• Technical Committee: E37 - Thermal Measurements
• Drafting Committee: E37.01 - Calorimetry and Mass Loss

Relations

• Replaces: ASTM E1131-08(2014) - Standard Test Method for Compositional Analysis by Thermogravimetry
• Effective Date: 15-Mar-2020
• 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 E2040-19 - Standard Test Method for Mass Scale Calibration of Thermogravimetric Analyzers
• Effective Date: 01-Dec-2019
• Refers: ASTM E1142-15 - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-May-2015
• Refers: ASTM E1142-14b - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 15-Aug-2014
• Refers: ASTM E473-14 - Standard Terminology Relating to Thermal Analysis and Rheology
• Effective Date: 15-Aug-2014
• Refers: ASTM E1142-14a - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Apr-2014
• Refers: ASTM E2040-08(2014) - Standard Test Method for Mass Scale Calibration of Thermogravimetric Analyzers
• Effective Date: 15-Mar-2014
• Refers: ASTM E1142-14 - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 15-Feb-2014
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM E1142-12 - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Sep-2012
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM E1142-11b - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Aug-2011
• Refers: ASTM E1142-11a - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 15-Jun-2011

Overview

ASTM E1131-20: Standard Test Method for Compositional Analysis by Thermogravimetry provides a widely recognized protocol for determining the composition of solid and liquid materials. Using thermogravimetric analysis (TGA), this method enables laboratories and industry professionals to quantify the amount of highly volatile matter, medium volatile matter, combustible materials, and ash content in various compounds. The procedure is effective for temperatures ranging from room temperature up to 1000 °C and is applicable across a wide spectrum of materials with component concentrations between 1% and 100% by weight.

This standard is crucial for quality control, material screening, and resolving issues around material composition, providing a reliable framework for the comparison of unknown samples to known standards.

Key keywords: thermogravimetry, compositional analysis, volatile matter, ash content, TGA, ASTM E1131-20, combustible material, quality control, material screening

Key Topics

• Thermogravimetric Analysis (TGA):

  • Fundamental technique wherein the mass of a substance is measured as a function of temperature or time while being heated in a controlled environment
  • Enables distinction between highly volatile matter, medium volatile matter, combustible content, and ash

• Operational Guidelines:

  • Suitable for both solids and liquids
  • Employs inert and reactive gas atmospheres (e.g., nitrogen/argon, air/oxygen)
  • Each component is measured within specific temperature ranges for optimal accuracy
  • Strict adherence to SI units

• Interpretation and Utility:

  • Used for routine quality checks and product consistency validation
  • Assists in identifying specific material characteristics and potential performance implications
  • Capable of indicating issues such as lubricant degradation (from increasing soot content) or compliance of carbon-to-polymer ratios in plastics and elastomers

• Reporting Requirements:

  • Detailed description of specimen, pretreatment, TGA apparatus, temperature and gas parameters, number of determinations, and original thermal curve
  • Results reported as weight percent for each component

Applications

• Quality Control:

  • Verification of batch-to-batch consistency in manufacturing of polymers, elastomers, lubricants, and composites

• Material Screening:

  • Rapid assessment of new or unknown materials against established standards
  • Identification of components in blends or recycled materials

• Performance Analysis:

  • Helps determine if material compositions fall within defined ranges required for mechanical properties or stability, especially with plastics, rubbers, and reinforced composites
  • Facilitates ranking and selection of coals and cokes based on their carbon, volatile, and ash content

• Problem Solving:

  • Detection of contamination, improper formulation, or degradation (e.g., tracking soot accumulation in lubricating oils)
  • Identifying noncompliance with specification limits for inert fillers or ash in finished products

Related Standards

• ASTM D3172 - Practice for Proximate Analysis of Coal and Coke: Routine determination of coal and coke composition, highly relevant for energy sector applications.
• ASTM E473 - Terminology Relating to Thermal Analysis and Rheology: Definitions commonly used in thermal analysis.
• ASTM E691 - Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method: Establishing test method reliability.
• ASTM E1142 - Terminology Relating to Thermophysical Properties: Additional supporting definitions.
• ASTM E1582 - Test Method for Temperature Calibration of Thermogravimetric Analyzers: Calibration procedure to ensure accuracy.
• ASTM E2040 - Test Method for Mass Scale Calibration of Thermogravimetric Analyzers: Mass calibration guidance.
• ISO 11358 - Plastics-Thermogravimetry (TG) of Polymers - General Principles: Comparable international guideline for TGA of polymers.

This standard plays a key role in laboratories and industries where thermogravimetric compositional analysis is integral to product quality, regulatory compliance, and advanced material development.

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: E1131 − 20
Standard Test Method for
Compositional Analysis by Thermogravimetry
This standard is issued under the fixed designation E1131; 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 E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 This test method provides a general technique incorpo-
E1142 Terminology Relating to Thermophysical Properties
rating thermogravimetry to determine the amount of highly
E1582 Test Method for Temperature Calibration of Thermo-
volatile matter, medium volatile matter, combustible material,
gravimetric Analyzers
and ash content of compounds. This test method will be useful
E2040 Test Method for Mass Scale Calibration of Thermo-
in performing a compositional analysis in cases where agreed
gravimetric Analyzers
upon by interested parties.
2.2 ISO Standards:
1.2 This test method is applicable to solids and liquids.
ISO 11358 Plastics-Thermogravimetry (TG) of Polymers —
1.3 Thetemperaturerangeoftestistypicallyroomtempera-
General Principles
ture to 1000 °C. Composition between 1 weight % and 100
3. Terminology
weight % of individual components may be determined.
3.1 Definitions:
1.4 This test method utilizes an inert and reactive gas
3.1.1 Many of the technical terms used in this test method
environment.
are defined in Terminologies E473 and E1142, including
1.5 The values stated in SI units are to be regarded as
Celsius, derivative, Kelvin, peak, plateau, thermogravimetric
standard. No other units of measurement are included in this
analysis, and thermogravimetry.
standard.
3.2 Definitions of Terms Specific to This Standard:
1.6 This standard does not purport to address all of the
3.2.1 highly volatile matter—moisture, plasticizer, residual
safety concerns, if any, associated with its use. It is the
solvent or other low boiling (200 °C or less) components.
responsibility of the user of this standard to establish appro-
3.2.2 medium volatile matter—medium volatility materials
priate safety, health, and environmental practices and deter-
such as oil and polymer degradation products. In general, these
mine the applicability of regulatory limitations prior to use.
materials degrade or volatilize in the temperature range 200 °C
1.7 This international standard was developed in accor-
to 750 °C.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
3.2.3 combustible material—oxidizablematerialnotvolatile
Development of International Standards, Guides and Recom-
(in the unoxidized form) at 750 °C, or some stipulated
mendations issued by the World Trade Organization Technical
temperature dependent on material. Carbon is an example of
Barriers to Trade (TBT) Committee.
such a material.
3.2.4 ash—nonvolatile residues in an oxidizing atmosphere
2. Referenced Documents
which may include metal components, filler content or inert
2.1 ASTM Standards:
reinforcing materials.
D3172 Practice for Proximate Analysis of Coal and Coke
3.2.5 mass loss plateau—a region of a thermogravimetric
E473 Terminology Relating to Thermal Analysis and Rhe-
curve with a relatively constant mass.
ology
4. Summary of Test Method
ThistestmethodisunderthejurisdictionofASTMCommitteeE37onThermal
4.1 This test method is an empirical technique using ther-
Measurements and is the direct responsibility of Subcommittee E37.01 on Calo-
rimetry and Mass Loss. mogravimetry in which the mass of a substance, heated at a
Current edition approved March 15, 2020. Published April 2020. Originally
controlled rate in an appropriate environment, is recorded as a
approved in 1986. Last previous edition approved in 2014 as E1131 – 08 (2014).
function of time or temperature. Mass loss over specific
DOI: 10.1520/E1131-20.
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 Available from International Organization for Standardization (ISO), 1, ch. de
the ASTM website. la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1131 − 20
temperature ranges and in a specific atmosphere provide a 7. Apparatus
compositional analysis of that substance.
7.1 The essential equipment required to provide the mini-
mum thermogravimetric analyzer capability for this test
5. Significance and Use
method includes:
5.1 This test method is intended for use in quality control, 7.1.1 A thermobalance, composed of (1) a furnace to
material screening, and related problem solving where a provide uniform controlled heating or a specimen to a constant
compositional analysis is desired or a comparison can be made temperature or at a constant rate within the 25 °C to 1000 °C
with a known material of the same type. temperature range of this test method; (2) a temperature sensor
toprovideanindicationofthespecimen/furnacetemperatureto
5.2 The parameters described should be considered as
61 °C; (3) an electrobalance to continuously measure the
guidelines. They may be altered to suit a particular analysis,
specimen mass with a minimum capacity of 30 mg and a
provided the changes are noted in the report.
sensitivity of 61 µg; and (4) a means of sustaining the
5.3 Theproportionofthedeterminedcomponentsinagiven
specimen/container under atmosphere control with a purge rate
mixture or blend may indicate specific quality or end use
of 10 mL/min to 100 6 5 mL/min.
performance characteristics. Particular examples include the
7.1.2 A temperature controller, capable of executing a
following:
specifictemperatureprogrambyoperatingthefurnacebetween
5.3.1 Increasing soot (carbon) content of used diesel lubri- selected temperature limits at a rate of temperature change
cating oils indicates decreasing effectiveness. between 10 °C/min and 100 °C/min constant to within 61%
for a minimum of 100 min.
5.3.2 Specific carbon-to-polymer ratio ranges are required
in some elastomeric and plastic parts in order to achieve 7.1.3 A data collection device, to provide a means of
desired mechanical strength and stability. acquiring, storing, and displaying measured or calculated
signals, or both. The minimum output signals required for
5.3.3 Some filled elastomeric and plastic products require
Thermogravimetric analyzers are mass, temperature, and time.
specific inert content (for example, ash, filler, reinforcing
agent, etc.) to meet performance specifications.
NOTE 1—The capability to display the first derivative of the signal may
5.3.4 The volatile matter, fixed carbon, and ash content of
be useful in the measurement of obscure thermostability ranges.
coal and coke are important parameters. The “ranking” of coal
7.1.4 Containers (pans, crucibles, and so forth), which are
increases with increasing carbon content and decreasing vola-
inert to the specimen and which will remain dimensionally
tile and hydrocarbon, (medium volatility) content.
stable within the temperature limits of this test method.
7.2 Gas flow control device,withthecapabilityofswitching
6. Interferences
between inert and reactive gases.
6.1 This test method depends upon distinctive thermostabil-
ity ranges of the determined components as a principle of the
8. Reagents and Materials
test. For this reason, materials which have no well-defined
8.1 An inert compressed gas such as argon or nitrogen and
thermostable range, or whose thermostabilities are the same as
a reactive compressed gas such as air or oxygen are required
other components, may create interferences. Particular ex-
for this test method.
amples include the following:
6.1.1 Oil-filled elastomers have such high molecular weight
8.2 Purity of Purge Gases:
oilsandsuchlowmolecularweightpolymercontentthattheoil
8.2.1 0.01 % maximum total impurity.
and polymer may not be separated based upon temperature
8.2.2 1.0 µg/g water impurity maximum.
stability.
8.2.3 1.0 µg/g hydrocarbon impurity maximum.
6.1.2 Ash content materials (metals) are slowly oxidized at
8.2.4 The inert purge gas must not contain more than 10
high temperatures and in an air atmosphere, so that their mass
µg/g oxygen.
increases (or decreases) with time. Under such conditions, a
specific temperature or time region must be identified for the
9. Test Specimen
measurement of that component.
9.1 Specimens are ordinarily measured as received. If some
6.1.3 Polymers, especially neoprene and acrylonitrile buta-
heatormechanicaltreatmentisappliedtothespecimenpriorto
diene rubber (NBR), carbonize to a considerable extent, giving
test, this treatment shall be noted in the report.
low values for the polymer and high values for the carbon.
Approximate corrections can be made for this if the type of
9.2 Sincetheapplicablesamplesmaybemixturesorblends,
polymer is known.
take care to ensure that the analyzed specimen is representative
6.1.4 Certain pigments used in rubber lose weight on of the sample from which it is taken. If the sample is a liquid,
heating. For example, some pigments exhibit water loss in the mixing prior to taking the specimen is sufficient to ensure this
range 500 °C to 600 °C, resulting in high polymer values. consideration. If the sample is a solid, take several specimens
Others, such as calcium carbonate, release carbon dioxide from different areas of the sample and either combine for a
(CO ) upon decomposition at 825 °C, that may result in high single determination, or each run separately with the final
carbonvalues.Theextentofinterferenceisdependentuponthe analysis representing an average of the determinations. Note
type and quantity of pigment present. the number of determinations in the report.
E1131 − 20
10. Calibration 11.10.1 Ifadistinctplateauisnotobservedinthisrange,the
atmosphere change is made based on the zero slope indication
10.1 Calibrate the mass signal from the apparatus according
of the recorded first derivative or upon some agreed upon
to Test Method E2040.
temperature. Suggested temperatures for this region are given
10.2 Calibrate the temperature signal from the apparatus
in Table 1.
according to Practice E1582.
11.10.2 The resolution of this region may be enhanced,
wherecarbonispresentinlargequantitiesorofspecialinterest,
11. Procedure
by maintaining the specimen at constant temperature for
11.1 Establish the inert (nitrogen) and reactive (air or
several minutes after switching environments.
oxygen) gases at the desired flow rates. For most analyses, this
11.11 The analysis is complete upon the establishment of a
rate will be in the range of 10 mL/min to 100 mL/min. Higher
mass loss plateau following the introduction of the reactive
flow rates may be used for some analyses, particularly when
gas.
utilizing high heating rates.
11.12 Switch to the inert purge gas.
11.2 Switch the purge gas to the inert (nitrogen) gas.
11.13 Calculate and report the sample composition.
11.3 Zero the mass signal and tare the balance.
11.4 Open the apparatus to expose the specimen holder.
12. Calculation
11.5 Prepare the specimen as outlined in 9.2 and carefully
12.1 Highly volatile matter is represented by a mass loss
place it in the specimen holder. Typically, a sample mass of 10
measured between the starting temperature and Temperature X
to 30 mg shall be used (see Table 1).
(see Fig. 1).Temperature X should be taken in the center of the
first mass loss plateau or, if no resolvable plateau exists, at an
NOTE 2—Specimens smaller
...

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: E1131 − 08 (Reapproved 2014) E1131 − 20
Standard Test Method for
Compositional Analysis by Thermogravimetry
This standard is issued under the fixed designation E1131; 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 provides a general technique incorporating thermogravimetry to determine the amount of highly volatile
matter, medium volatile matter, combustible material, and ash content of compounds. This test method will be useful in performing
a compositional analysis in cases where agreed upon by interested parties.
1.2 This test method is applicable to solids and liquids.
1.3 The temperature range of test is typically room temperature to 1000°C. 1000 °C. Composition between 1 weight % and 100
weight % of individual components may be determined.
1.4 This test method utilizes an inert and reactive gas environment.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard is related ISO 11358 but is more detailed and specific.
1.6 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.
1.7 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:
D3172 Practice for Proximate Analysis of Coal and Coke
E473 Terminology Relating to Thermal Analysis and Rheology
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1142 Terminology Relating to Thermophysical Properties
E1582 Test Method for Temperature Calibration of Thermogravimetric Analyzers
E2040 Test Method for Mass Scale Calibration of Thermogravimetric Analyzers
2.2 ISO Standards:
ISO 11358 Plastics-Thermogravimetry (TG) of Polymers — General Principles
3. Terminology
3.1 Definitions:
3.1.1 Many of the technical terms used in this test method are defined in Terminologies E473 and E1142., including Celsius,
derivative, Kelvin, peak, plateau, thermogravimetric analysis, and thermogravimetry.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 highly volatile matter—moisture, plasticizer, residual solvent or other low boiling (200°C (200 °C or less) components.
This test method is under the jurisdiction of ASTM Committee E37 on Thermal Measurements and is the direct responsibility of Subcommittee E37.01 on Calorimetry
and Mass Loss.
Current edition approved March 15, 2014March 15, 2020. Published April 2014April 2020. Originally approved in 1986. Last previous edition approved in 20082014 as
E1131 – 08.E1131 – 08 (2014). DOI: 10.1520/E1131-08R14.10.1520/E1131-20.
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.
Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1131 − 20
3.2.2 medium volatile matter—medium volatility materials such as oil and polymer degradation products. In general, these
materials degrade or volatilize in the temperature range 200 °C to 750°C.750 °C.
3.2.3 combustible material—oxidizable material not volatile (in the unoxidized form) at 750°C, 750 °C, or some stipulated
temperature dependent on material. Carbon is an example of such a material.
3.2.4 ash—nonvolatile residues in an oxidizing atmosphere which may include metal components, filler content or inert
reinforcing materials.
3.2.5 mass loss plateau—a region of a thermogravimetric curve with a relatively constant mass.
4. Summary of Test Method
4.1 This test method is an empirical technique using thermogravimetry in which the mass of a substance, heated at a controlled
rate in an appropriate environment, is recorded as a function of time or temperature. Mass loss over specific temperature ranges
and in a specific atmosphere provide a compositional analysis of that substance.
5. Significance and Use
5.1 This test method is intended for use in quality control, material screening, and related problem solving where a
compositional analysis is desired or a comparison can be made with a known material of the same type.
5.2 The parameters described should be considered as guidelines. They may be altered to suit a particular analysis, provided
the changes are noted in the report.
5.3 The proportion of the determined components in a given mixture or blend may indicate specific quality or end use
performance characteristics. Particular examples include the following:
5.3.1 Increasing soot (carbon) content of used diesel lubricating oils indicates decreasing effectiveness.
5.3.2 Specific carbon-to-polymer ratio ranges are required in some elastomeric and plastic parts in order to achieve desired
mechanical strength and stability.
5.3.3 Some filled elastomeric and plastic products require specific inert content (for example, ash, filler, reinforcing agent, etc.)
to meet performance specifications.
5.3.4 The volatile matter, fixed carbon, and ash content of coal and coke are important parameters. The “ranking” of coal
increases with increasing carbon content and decreasing volatile and hydrocarbon, (medium volatility) content.
6. Interferences
6.1 This test method depends upon distinctive thermostability ranges of the determined components as a principle of the test.
For this reason, materials which have no well-defined thermostable range, or whose thermostabilities are the same as other
components, may create interferences. Particular examples include the following:
6.1.1 Oil-filled elastomers have such high molecular weight oils and such low molecular weight polymer content that the oil
and polymer may not be separated based upon temperature stability.
6.1.2 Ash content materials (metals) are slowly oxidized at high temperatures and in an air atmosphere, so that their mass
increases (or decreases) with time. Under such conditions, a specific temperature or time region must be identified for the
measurement of that component.
6.1.3 Polymers, especially neoprene and acrylonitrile butadiene rubber (NBR), carbonize to a considerable extent, giving low
values for the polymer and high values for the carbon. Approximate corrections can be made for this if the type of polymer is
known.
6.1.4 Certain pigments used in rubber lose weight on heating. For example, some pigments exhibit water loss in the range 500
°C to 600°C, 600 °C, resulting in high polymer values. Others, such as calcium carbonate, release carbon dioxide (CO ) upon
decomposition at 825°C, 825 °C, that may result in high carbon values. The extent of interference is dependent upon the type and
quantity of pigment present.
7. Apparatus
7.1 The essential equipment required to provide the minimum thermogravimetric analyzer capability for this test method
includes:
7.1.1 A thermobalance, composed of (1) a furnace to provide uniform controlled heating or a specimen to a constant temperature
or at a constant rate within the 25 °C to 1000°C 1000 °C temperature range of this test method; (2) a temperature sensor to provide
an indication of the specimen/furnace temperature to 61°C; 61 °C; (3) an electrobalance to continuously measure the specimen
mass with a minimum capacity of 30 mg and a sensitivity of 61 μg; and (4) a means of sustaining the specimen/container under
atmosphere control with a purge rate of 10 mL/min to 100 6 5 mL/min.
7.1.2 A temperature controller, capable of executing a specific temperature program by operating the furnace between selected
temperature limits at a rate of temperature change between 10 °C/min and 100°C/min 100 °C/min constant to within 61 % for
a minimum of 100 min.
E1131 − 20
7.1.3 A data collection device, to provide a means of acquiring, storing, and displaying measured or calculated signals, or both.
The minimum output signals required for Thermogravimetric analyzers are mass, temperature, and time.
NOTE 1—The capability to display the first derivative of the signal may be useful in the measurement of obscure thermostability ranges.
7.1.4 Containers (pans, crucibles, and so forth), which are inert to the specimen and which will remain dimensionally stable
within the temperature limits of this test method.
7.2 Gas flow dontrolcontrol device, with the capability of switching between inert and reactive gases.
8. Reagents and Materials
8.1 An inert compressed gas such as argon or nitrogen and a reactive compressed gas such as air or oxygen are required for
this test method.
8.2 Purity of Purge Gases:
8.2.1 0.01 % maximum total impurity.
8.2.2 1.0 μg/g water impurity maximum.
8.2.3 1.0 μg/g hydrocarbon impurity maximum.
8.2.4 The inert purge gas must not contain more than 10 μg/g oxygen.
9. Test Specimen
9.1 Specimens are ordinarily measured as received. If some heat or mechanical treatment is applied to the specimen prior to
test, this treatment shall be noted in the report.
9.2 Since the applicable samples may be mixtures or blends, take care to ensure that the analyzed specimen is representative
of the sample from which it is taken. If the sample is a liquid, mixing prior to taking the specimen is sufficient to ensure this
consideration. If the sample is a solid, take several specimens from different areas of the sample and either combine for a single
determination, or each run separately with the final analysis representing an average of the determinations. Note the number of
determinations in the report.
10. Calibration
10.1 Calibrate the mass signal from the apparatus according to Test Method E2040.
10.2 Calibrate the temperature signal from the apparatus according to Practice E1582.
11. Procedure
11.1 Establish the inert (nitrogen) and reactive (air or oxygen) gases at the desired flow rates. For most analyses, this rate will
be in the range of 10 mL/min to 100 mL/min. Higher flow rates may be used for some analyses, particularly when utilizing high
heating rates.
11.2 Switch the purge gas to the inert (nitrogen) gas.
11.3 Zero the mass signal rand tare the balance.
11.4 Open the apparatus to expose the specimen holder.
11.5 Prepare the specimen as outlined in 9.2 and carefully place it in the specimen holder. Typically, a sample mass of 10 to
30 mg shall be used (see Table 1).
NOTE 2—Specimens smaller than 10 mg may be used if larger specimens cause instrument fouling or poor reproducibility.
11.6 Position the specimen temperature sensor to the same location used in calibration. (See Section 10.)
TABLE 1 Suggested Compositional Analysis Parameters
Purge Heating Gas
Temperature
Sample Flow Rate mL/
Material Time Rate Switchover
A
Size mg min B
Initial X Y Z
Min °C/min °C
Purge Heating Gas
Temperature
Sample Flow Rate mL/
Material Time Rate Switchover
A
B
Size mg min
Initial X Y Z
Min °C/min °C
coal 20 50 5 ambient 110 900 900 10 to 150 900
elastomers 20 50 2 ambient 325 550 750 10 600
thermoplastics 20 50 2 ambient 200 600 750 10 600
lubricants 20 40 to 500 1 50 150 600 750 10 to 100 600
thermosets 20 50 2 ambient 200 550 750 10 600
A
May differ depending upon instrument design.
B
Z is not necessarily the final temperature.
E1131 − 20
11.7 Enclose the specimen holder.
11.8 Record the initial mass. If the apparatus in use has provisions for direct percentage measurements, adjust to read 100 %.
11.9 Initiate the heating program within the desired temperature range. See Table 1 for suggested heating rates and temperature
ranges. Record the specimen mass change continuously over the temperature interval.
11.9.1 The mass loss profile may be expressed in either
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