1、Designation: E2550 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 number in pa
2、rentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes the assessment of materialthermal stability through the determination of the temperatureat which the materials start to
3、decompose or react and theextent of the mass change using thermogravimetry. The testmethod uses minimum quantities of material and is applicableover the temperature range from ambient to 800C.1.2 The absence of reaction or decomposition is used as anindication of thermal stability in this test metho
4、d 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 establisha safe operating or storage temperature. It may be used inconjunction w
5、ith other test methods (for example, Test Meth-ods E487 and E537, and Guide E1981) as part of a hazardanalysis of a material.1.5 This test method is normally applicable to reaction ordecomposition occurring in the range from room temperatureto 800C. The temperature range may be extended dependingon
6、the instrumentation used.1.6 This test method may be performed in an inert, areactive or self-generated atmosphere.1.7 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.8 This standard does not purport to address all of thesafet
7、y concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.9 This international standard was developed in accor-dance
8、with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standa
9、rds:2E473 Terminology Relating to Thermal Analysis and Rhe-ologyE487 Test Method for Constant-Temperature Stability ofChemical MaterialsE537 Test Method for The Thermal Stability of Chemicalsby Differential Scanning CalorimetryE691 Practice for Conducting an Interlaboratory Study toDetermine the Pre
10、cision of a Test MethodE967 Test Method for Temperature Calibration of Differen-tial Scanning Calorimeters and Differential Thermal Ana-lyzersE1142 Terminology Relating to Thermophysical PropertiesE1445 Terminology Relating to Hazard Potential of Chemi-calsE1582 Practice for Calibration of Temperatu
11、re Scale forThermogravimetryE1981 Guide for Assessing Thermal Stability of Materialsby Methods of Accelerating Rate CalorimetryE2040 Test Method for Mass Scale Calibration of Thermo-gravimetric Analyzers3. Terminology3.1 Definitions:3.1.1 Specific technical terms used in this test method aredefined
12、in Terminologies E473, E1142, and E1445. Theseterms include thermogravimetry (TG), thermogravimetricanalysis (TGA), thermal stability, onset temperature (To),derivative, and TG curve.3.2 Definitions of Terms Specific to This Standard:3.2.1 derivative thermogravimetry or DTG curve, na dis-play of the
13、 first derivative of thermogravimetry data withrespect to temperature or time.1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on Calo-rimetry and Mass Loss.Current edition approved Sept. 1, 2017. Publishe
14、d September 2017. Originallyapproved in 2007. Last previous edition approved in 2011 as E2550 11. DOI:10.1520/E2550-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer
15、to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established
16、 in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.2 mass change plateau, na region of the thermogra-vimetry curve with a relatively constant mass; it is acco
17、mpa-nied by a minimum in the DTG curve for a mass loss, or amaximum for a mass gain.4. Summary of Test Method4.1 A sample of the material to be examined is placed in aninert container and then heated at a controlled rate ()of1Cmin-1to 20C min-1under a controlled atmosphere. The samplemass is recorde
18、d continuously as a function of time andtemperature.4.2 When the sample undergoes a reaction or thermaldecomposition involving a mass change, that change is indi-cated by a departure from the initially established baseline ofthe mass record (see Fig. 1).4.3 The onset temperature and mass changes are
19、 determinedand reported.5. Significance and Use5.1 Thermogravimetry provides a rapid method for deter-mining the thermal decomposition and reaction mass change ofa material.5.2 This test method is useful in detecting potentiallyhazardous reactions and in estimating the temperatures atwhich these rea
20、ctions occur. This test method is recommendedas a screening test for detecting the thermal hazards of anuncharacterized material or mixture (see Section 8).5.3 Energetic materials, pharmaceuticals and polymers areexamples of materials for which this test might be useful. Thistest is especially usefu
21、l for materials having melting points thatoverlap with the onset of reaction or decomposition.NOTE 1In Differential Scanning Calorimetry (DSC), the meltingendotherm may interfere with the determination of the onset temperaturefor reaction or decomposition.5.4 This test is not suitable for materials
22、that sublime orvaporize in the temperature range of interest. A sample withvolatile impurities needs to be purified prior to testing bythermogravimetric analysis. Alternatively, the sample can betested as is, however, special caution is required during the dataanalysis. The mass loss due to the loss
23、 of impurity should notinterfere with the determination of reaction or decompositiontemperature.5.5 The four significant criteria of this test method are: thedetection of a sample mass change; the extent of the masschange; the approximate temperature at which the eventoccurs; the observance of effec
24、ts due to the atmosphere.6. Limitations6.1 Many environmental factors affect the existence, mag-nitude and onset temperature of a particular reaction ordecomposition. Some of these, including heating rate, instru-mental sensitivity, and atmosphere reactivity, will affect thedetectability of a reacti
25、on or decomposition using this proce-dure. Therefore, it is imperative that the results obtained fromthe application of this test method be viewed only as anindication of the thermal stability of a material.6.2 This test method can only be used to detect reaction ordecomposition that involves a mass
26、 change, such as a produc-tion of gaseous species or a mass gain in reactive atmosphere.This test method is not suitable for materials that sublime orvaporize in the temperature of interest.6.3 This test method may not be reliable for heterogeneoussamples.NOTE 2For heterogeneous samples, it is recom
27、mended to performreplicate measurements to determine the variability of the results. Ifinconsistent results are obtained, the study should be carried out usinglarger-scale apparatus, such as accelerating rate calorimetry.7. Apparatus7.1 Thermogravimetric Analyzer (TGA)The essential in-strumentation
28、required to provide the minimum thermogravi-metric analytical capability for this test method includes:7.1.1 A thermobalance composed of:FIG. 1 Typical Thermogravimetry and Derivative Thermogravimetry CurvesE2550 1727.1.1.1 A furnace to provide uniform controlled heating of aspecimen to a constant t
29、emperature or at a constant rate withinthe applicable temperature range of ambient to 600C.7.1.1.2 A temperature sensor to provide an indication of thespecimen/furnace temperature to 60.1C.7.1.1.3 A continuously recording balance to measure thespecimen mass with a minimum capacity of 10 mg and asens
30、itivity of 610 g.NOTE 3An apparatus with a larger capacity can also be used. Thesensitivity must be at least 60.1 mass %.7.1.1.4 A means of maintaining the specimen/containerunder atmospheric control of an inert or reactive gas of99.9+ % purity at a purge rate of 20 mL min-1to 100mL min-16 5mLmin-1.
31、NOTE 4Purge rate may vary depending on the instrument used.Excessive purge rates should be avoided as this may introduce interfer-ences due to turbulence effects and temperature gradients.NOTE 5Experiments can also be performed in a self generatedatmosphere. DSC sealed containers with a pinhole of 2
32、5-m to 380-mdiameter have been shown to establish saturation of a gaseous selfgenerated atmosphere.37.1.2 A temperature controller capable of executing a spe-cific temperature program by operating the furnace betweenselected temperature limits at a rate of temperature changebetween 1C min-1and 20C m
33、in-1to within 60.1C min-1.7.1.3 A recording device capable of recording and display-ing on the Y-axis any fraction of the specimen mass signal(TGA curve) including the signal noise as a function of anyfraction of the temperature (or time) signal on the X-axisincluding the signal noise.7.1.4 Containe
34、rs (pans, crucibles, etc.) that are inert to thespecimen and that will remain gravimetrically stable within thetemperature limits of this test method.NOTE 6For experiments in a self generated atmosphere, DSC sealedcontainers with pinhole of 25-m to 380-m diameter can be used.7.2 Auxiliary equipment
35、necessary or useful in conductingthis test method includes:7.2.1 A balance with a capacity of 100 mg or more to weighspecimens or containers, or both, to 60.1 mg.7.2.2 Device to encapsulate the specimen in DSC sealablecontainers for self-generated atmosphere studies.8. Safety Precautions8.1 The use
36、of this test method as an initial test for materialwhose potential hazards are unknown requires that precautionsbe taken during the sample preparation and testing.8.2 Larger specimens (5 mg) should be used only afterconsideration is given to the potential for hazardous reac-tion(s). For energetic ma
37、terial or materials whose characteris-tics are unknown, it is safest to start with a specimen mass ofno more than 1 mg and a lower heating rate (1C min-1to 10Cmin-1).8.3 When particle size reduction by grinding is necessary,the user of the test method shall presume that the material issensitive to s
38、timuli such as friction and electrostatic discharge.Accordingly, appropriate tests shall be conducted on thosematerials prior to grinding. Use of suitable protective equip-ment is always recommended when preparing materials ofunknown hazard. If a Safety Data Sheet is available, it shall beacquired a
39、nd studied prior to handling unknown materials.8.4 Toxic or corrosive effluents, or both, may be releasedwhen heating the material and could be harmful to thepersonnel or the apparatus. Use of an exhaust system to removesuch effluents is highly recommended.9. Sampling9.1 Samples shall be representat
40、ive of the material beingstudied including particle size and purity.9.2 In the absence of other information, the samples areassumed to be analyzed as received. If a treatment, such asdrying, is applied to the sample prior to analysis, this treatmentand any resulting mass change must be noted in the
41、report.9.3 The selection of specimen mass depends upon themagnitude of hazard associated with the material, the sensitiv-ity of the instrument, the heating rate and the specimenhomogeneity. This test method should be carried out on assmall of a quantity of material as possible, while specimens arest
42、ill large enough to be representative of the material and toexhibit adequate signals. Typical specimen mass is between 1mg and 10 mg.NOTE 7The particle size of the specimen should be considered, sincethicker specimens may show transition broadening due to the thermalconductivity lag into the specime
43、n cores.10. Preparation of Apparatus10.1 Prepare the thermogravimetric analyzer using anyprocedures described in the manufacturers operations manual.10.2 Place the temperature sensor in the proper position inaccordance with the manufacturers operations manual.NOTE 8Care must be taken to ensure that
44、the specimen container isnot in contact in any way with the sensor, unless the thermogravimetricanalyzer was designed with the temperature sensor fixed to the crucibleholder. It is also important that the temperature sensor is not moved aftertemperature calibration has been carried out.10.3 Maintain
45、 a constant flow of purge gas for the furnace inthe range from 20 mL min-1to 100 mL min-1throughout theexperiment.11. Calibration11.1 Calibrate the mass signal using Test Method E2040 orinstrument manufacturers guidelines and record details.11.2 Calibrate the furnace temperature in accordance withPr
46、actice E1582 using the same heating rate, purge gas, flowrate and temperature sensor position to be used for subsequentspecimens tests.NOTE 9For simultaneous thermogravimetic analyzers/differentialthermal analyzers, temperature calibration may be performed using TestMethod E967.3Kwok, Q., and Seyler
47、, R. J., “Volatility Rate by Thermogravimetry,” Journal ofThermal Analysis and Calorimetry, Vol 83, No. 1, 2006, pp. 117123.E2550 17312. Recommended Condition of Tests12.1 Specimen Mass5 mg of specimen is generally con-sidered adequate. Decrease the specimen mass to 1 mg if thecharacteristics of mat
48、erials are unknown.NOTE 10For energetic material, it is recommended to use a specimenmass of no more than 1.0 mg.12.2 Heating RateA rate of 10C min-1to 20C min-1isconsidered normal.NOTE 11The onset temperature is affected by heating rate. Therefore,only results obtained at the same heating rate shal
49、l be compared.NOTE 12A lower heating rate (1C min-1to 10C min-1) should beused when a complex change of mass is encountered.NOTE 13For energetic material, it is recommended to use a lowerheating rate (1C min-1to 10C min-1). For primary explosives, it issuggested to start with a heating rate of no more than 3C min-1.12.3 Temperature RangeThe temperature typically rangesfrom room temperature to 600C.13. Procedure13.1 Tare an empty and clean specimen container.13.2 Weigh the specimen with a mass within 10 mass % ofthe ta
