1、Designation: E2550 11E2550 17Standard Test Method forThermal Stability by Thermogravimetry1This standard is issued under the fixed designation E2550; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numb
2、er in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method coversdescribes the assessment of material thermal stability through the determination of the temperatureat which the mate
3、rials start to decompose or react and the extent of the mass change using thermogravimetry. The test method usesminimum quantities of material and is applicable over the temperature range from ambient to 800C.1.2 The absence of reaction or decomposition is used as an indication of thermal stability
4、in this test method under theexperimental conditions used.1.3 This test method may be performed on solids or liquids, which do not sublime or vaporize in the temperature range ofinterest.1.4 This test method shall not be used by itself to establish a safe operating or storage temperature. It may be
5、used in conjunctionwith other test methods (for example, Test Methods E487, and E537, and Guide E1981) as part of a hazard analysis of a material.1.5 This test method is normally applicable to reaction or decomposition occurring in the range from room temperature to 800C. 800C. The temperature range
6、 may be extended depending on the instrumentation used.1.6 This test method may be performed in an inert, a reactive or self-generated atmosphere.1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.8 There is no ISO standard
7、 equivalent to this test method.1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety, health and environmental practices and determine the applicability ofregula
8、tory limitations prior to use.1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations
9、prior to use. This standard may involve hazardous materials, operations, and equipment.1.9 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Gu
10、ides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and RheologyE487 Test Method for Constant-Temperature Stability of Chemical MaterialsE537 Test Method fo
11、r The Thermal Stability of Chemicals by Differential Scanning CalorimetryE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE967 Test Method for Temperature Calibration of Differential Scanning Calorimeters and Differential Thermal AnalyzersE1142 Termino
12、logy Relating to Thermophysical PropertiesE1445 Terminology Relating to Hazard Potential of ChemicalsE1582 Practice for Calibration of Temperature Scale for Thermogravimetry1 This test method is under the jurisdiction of ASTM Committee E37 on Thermal Measurements and is the direct responsibility of
13、Subcommittee E37.01 on Calorimetryand Mass Loss.Current edition approved April 1, 2011Sept. 1, 2017. Published May 2011September 2017. Originally approved in 2007. Last previous edition approved in 20072011 asE2550 07.E2550 11. DOI: 10.1520/E2550-11.10.1520/E2550-17.2 For referencedASTM standards, v
14、isit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM stan
15、dard an indication of what changes have been made to the previous version. Becauseit 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 versionof the standard as published by AST
16、M is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E1981 Guide for Assessing Thermal Stability of Materials by Methods of Accelerating Rate CalorimetryE2040 Test Method for Mass Scale Calibrati
17、on of Thermogravimetric Analyzers3. Terminology3.1 Definitions:3.1.1 Specific technical terms used in this test method are defined in Terminologies E473, E1142, and E1445. These termsinclude thermogravimetry (TG), thermogravimetric analysis (TGA), thermal stability,onset temperature (To), derivative
18、, and TGcurve.3.2 Definitions of Terms Specific to This Standard:3.2.1 derivative thermogravimetry or DTG curve, na plotdisplay of the first derivative of TGthermogravimetry data withrespect to temperature or time.3.2.2 mass change plateau, na region of the TGthermogravimetry curve with a relatively
19、 constant mass; it is accompaniedby a minimum in the DTG curve for a mass loss, or a maximum for a mass gain.4. Summary of Test Method4.1 A sample of the material to be examined is placed in an inert container and then heated at a controlled rate () of 1 1Cmin-1 to 20C min1-1 under a controlled atmo
20、sphere. The sample mass is recorded continuously as a function of time andtemperature.4.2 When the sample undergoes a reaction or thermal decomposition involving a mass change, that change is indicated by adeparture from the initially established baseline of the mass record (see Fig. 1).4.3 The onse
21、t temperature and mass changes are determined and reported.5. Significance and Use5.1 TGThermogravimetry provides a rapid method for determining the thermal decomposition and reaction mass change of amaterial.5.2 This test method is useful in detecting potentially hazardous reactions and in estimati
22、ng the temperatures at which thesereactions occur. This test method is recommended as a screening test for detecting the thermal hazards of an uncharacterizedmaterial or mixture (see Section 8).5.3 Energetic materials, pharmaceuticals and polymers are examples of materials for which this test might
23、be useful. This testis especially useful for materials having melting points that overlap with the onset of reaction or decomposition.NOTE 1In Differential Scanning Calorimetry (DSC), the melting endotherm may interfere with the determination of the onset temperature for reactionor decomposition.5.4
24、 This test is not suitable for materials that sublime or vaporize in the temperature range of interest. A sample with volatileimpurities needs to be purified prior to the TGA testing. testing by thermogravimetric analysis. Alternatively, the sample can betested as is, however, special caution is req
25、uired during the data analysis. The mass loss due to the loss of impurity should notinterfere with the determination of reaction or decomposition temperature.FIG. 1 Typical TGThermogravimetry and DTG Derivative Thermogravimetry CurvesE2550 1725.5 The four significant criteria of this test method are
26、: the detection of a sample mass change; the extent of the mass change;the approximate temperature at which the event occurs; the observance of effects due to the atmosphere.6. Limitations6.1 Many environmental factors affect the existence, magnitude and onset temperature of a particular reaction or
27、 decomposition.Some of these, including heating rate, instrumental sensitivity, and atmosphere reactivity, will affect the detectability of a reactionor decomposition using this procedure. Therefore, it is imperative that the results obtained from the application of this test methodbe viewed only as
28、 an indication of the thermal stability of a material.6.2 This test method can only be used to detect reaction or decomposition that involves a mass change, such as a productionof gaseous species or a mass gain in reactive atmosphere. This test method is not suitable for materials that sublime or va
29、porizein the temperature of interest.6.3 This test method may not be reliable for heterogeneous samples.NOTE 2For heterogeneous samples, it is recommended to perform replicate measurements to determine the variability of the results. If inconsistentresults are obtained, the study should be carried o
30、ut using larger-scale apparatus, such as accelerating rate calorimetry.7. Apparatus7.1 Thermogravimetric Analyzer (TGA)The essential instrumentation required to provide the minimum thermogravimetricanalytical capability for this practice test method includes:7.1.1 A thermobalance composed of:7.1.1.1
31、 Afurnace to provide uniform controlled heating of a specimen to a constant temperature or at a constant rate within theapplicable temperature range of this test method.ambient to 600C.7.1.1.2 A temperature sensor to provide an indication of the specimen/furnace temperature to 60.1C.7.1.1.3 A contin
32、uously recording balance to measure the specimen mass with a minimum capacity of 10 mg and a sensitivityof 610 g.NOTE 3An apparatus with a larger capacity can also be used. The sensitivity must be at least 60.1 mass %.7.1.1.4 A means of maintaining the specimen/container under atmospheric control of
33、 an inert or reactive gas of 99.9+ % purityat a purge rate of 20 mL min-1 to 100 65 mL min100 mL min 1-1 6 5 mL min-1.NOTE 4Purge rate may vary depending on the instrument used. Excessive purge rates should be avoided as this may introduce interferences due toturbulence effects and temperature gradi
34、ents.NOTE 5Experiments can also be performed in a self generated atmosphere. DSC sealed containers with a pinhole of 0.02525-m to 0.38 mm380-mdiameter have been shown to establish saturation of a gaseous self generated atmosphere.37.1.2 A temperature controller capable of executing a specific temper
35、ature program by operating the furnace between selectedtemperature limits at a rate of temperature change between 11C min-1 and 20C min1-1 to within 60.1C min 1-1.7.1.3 A recording device capable of recording and displaying on the Y-axis any fraction of the specimen mass signal (TGAcurve) including
36、the signal noise as a function of any fraction of the temperature (or time) signal on the X-axis including the signalnoise.7.1.4 Containers (pans, crucibles, etc.) that are inert to the specimen and that will remain gravimetrically stable within thetemperature limits of this test method.NOTE 6For ex
37、periments in a self generated atmosphere, DSC sealed containers with pinhole of 0.02525-m to 0.38 mm380-m diameter can be used.7.2 Auxiliary equipment necessary or useful in conducting this test method includes:7.2.1 A balance with a capacity of 100 mg or more to weigh specimens or containers, or bo
38、th, to 60.1 mg.7.2.2 Device to encapsulate the specimen in DSC sealable containers for self-generated atmosphere studies.8. Safety Precautions8.1 The use of this test method as an initial test for material whose potential hazards are unknown requires that precautions betaken during the sample prepar
39、ation and testing.8.2 Larger specimens (5 mg) should be used only after consideration is given to the potential for hazardous reaction(s). Forenergetic material or materials whose characteristics are unknown, it is safest to start with a specimen mass of no more than 1 mgand a lower heating rate (1
40、(1C min-1 to 10C min1-1).8.3 When particle size reduction by grinding is necessary, the user of the test method shall presume that the material is sensitiveto stimuli such as friction and electrostatic discharge. Accordingly, appropriate tests shall be conducted on those materials priorto grinding.
41、Use of suitable protective equipment is always recommended when preparing materials of unknown hazard. If aMaterial Safety Data Sheet is available, it shall be acquired and studied prior to handling unknown materials.3 Kwok, Q., and Seyler, R.J., R. J., “Volatility Rate by Thermogravimetry,” Journal
42、 of Thermal Analysis and Calorimetry, Vol 83, No. 1, 2006, p.pp. 117.123.E2550 1738.4 Toxic or corrosive effluents, or both, may be released when heating the material and could be harmful to the personnel orthe apparatus. Use of an exhaust system to remove such effluents is highly recommended.9. Sam
43、pling9.1 Samples shall be representative of the material being studied including particle size and purity.9.2 In the absence of other information, the samples are assumed to be analyzed as received. If a treatment, such as drying, isapplied to the sample prior to analysis, this treatment and any res
44、ulting mass change must be noted in the report.9.3 The selection of specimen mass depends upon the magnitude of hazard associated with the material, the sensitivity of theinstrument, the heating rate and the specimen homogeneity. This test method should be carried out on as small of a quantity ofmat
45、erial as possible, while specimens are still large enough to be representative of the material and to exhibit adequate signals.Typical specimen mass is between 1 mg and 10 mg.NOTE 7The particle size of the specimen should be considered, since thicker specimens may show transition broadening due to t
46、he thermalconductivity lag into the specimen cores.10. Preparation of Apparatus10.1 Prepare the TGA thermogravimetric analyzer using any procedures described in the manufacturers operations manual.10.2 Place the temperature sensor in the proper position in accordance with the manufacturers operation
47、s manual.NOTE 8Care must be taken to ensure that the specimen container is not in contact in any way with the sensor, unless the TGA thermogravimetricanalyzer was designed with the temperature sensor fixed to the crucible holder. It is also important that the temperature sensor is not moved aftertem
48、perature calibration has been carried out.10.3 Maintain a constant flow of purge gas for the furnace in the range from 20 mL min-1 to 100 mL min1-1 throughout theexperiment.11. Calibration11.1 Calibrate the mass signal using Practice Test Method E2040 or instrument manufacturers guidelines and recor
49、d details.11.2 Calibrate the furnace temperature in accordance with Practice E1582 using the same heating rate, purge gas, flow rate andtemperature sensor position to be used for subsequent specimens tests.NOTE 9For simultaneous thermogravimetic analyzers/differential thermal analyzers, temperature calibration may be performed using Test MethodE967.12. Recommended Condition of Tests12.1 Specimen Mass5 mg of specimen is generally considered adequate. Decrease the specimen mass to 1 mg if thecharacteristics of materials are unknown.NOTE 1
