ASTM E1131-2008(2014) Standard Test Method for Compositional Analysis by Thermogravimetry《用热解重量分析法进行成分分析的标准试验方法》.pdf

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1、Designation: E1131 08 (Reapproved 2014)Standard Test Method forCompositional Analysis by Thermogravimetry1This standard is issued under the fixed designation E1131; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r

2、evision. A number 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 provides a general technique incorpo-rating thermogravimetry to determine the amount of highlyvolatile matt

3、er, medium volatile matter, combustible material,and ash content of compounds. This test method will be usefulin performing a compositional analysis in cases where agreedupon by interested parties.1.2 This test method is applicable to solids and liquids.1.3 The temperature range of test is typically

4、 room tempera-ture to 1000C. Composition between 1 and 100 weight % ofindividual components may be determined.1.4 This test method utilizes an inert and reactive gasenvironment.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard

5、.1.6 This standard is related ISO 11358 but is more detailedand specific.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine

6、the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D3172 Practice for Proximate Analysis of Coal and CokeE473 Terminology Relating to Thermal Analysis and Rhe-ologyE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a T

7、est MethodE1142 Terminology Relating to Thermophysical PropertiesE1582 Practice for Calibration of Temperature Scale forThermogravimetryE2040 Test Method for Mass Scale Calibration of Thermo-gravimetric Analyzers2.2 ISO Standards:3ISO 11358 Plastics-Thermogravimetry (TG) of Polymers General Principl

8、es3. Terminology3.1 Definitions:3.1.1 Many of the technical terms used in this test methodare defined in Terminologies E473 and E1142.3.2 Definitions of Terms Specific to This Standard:3.2.1 highly volatile mattermoisture, plasticizer, residualsolvent or other low boiling (200C or less) components.3

9、.2.2 medium volatile mattermedium volatility materialssuch as oil and polymer degradation products. In general, thesematerials degrade or volatilize in the temperature range 200 to750C.3.2.3 combustible materialoxidizable material not volatile(in the unoxidized form) at 750C, or some stipulated temp

10、era-ture dependent on material. Carbon is an example of such amaterial.3.2.4 ashnonvolatile residues in an oxidizing atmospherewhich may include metal components, filler content or inertreinforcing materials.3.2.5 mass loss plateaua region of a thermogravimetriccurve with a relatively constant mass.

11、4. Summary of Test Method4.1 This test method is an empirical technique using ther-mogravimetry in which the mass of a substance, heated at acontrolled rate in an appropriate environment, is recorded as afunction of time or temperature. Mass loss over specifictemperature ranges and in a specific atm

12、osphere provide acompositional analysis of that substance.5. Significance and Use5.1 This test method is intended for use in quality control,material screening, and related problem solving where a1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direc

13、t responsibility of Subcommittee E37.01 on Calo-rimetry and Mass Loss.Current edition approved March 15, 2014. Published April 2014. Originallyapproved in 1986. Last previous edition approved in 2008 as E1131 08. DOI:10.1520/E1131-08R14.2For referenced ASTM standards, visit the ASTM website, www.ast

14、m.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, CP 56, CH-1211 Geneva 20, Swi

15、tzerland, http:/www.iso.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1compositional analysis is desired or a comparison can be madewith a known material of the same type.5.2 The parameters described should be considered asguidel

16、ines. 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 givenmixture or blend may indicate specific quality or end useperformance characteristics. Particular examples include thefollowing:5.3.1 Increasi

17、ng soot (carbon) content of used diesel lubri-cating oils indicates decreasing effectiveness.5.3.2 Specific carbon-to-polymer ratio ranges are requiredin some elastomeric and plastic parts in order to achievedesired mechanical strength and stability.5.3.3 Some filled elastomeric and plastic products

18、 requirespecific inert content (for example, ash, filler, reinforcingagent, etc.) to meet performance specifications.5.3.4 The volatile matter, fixed carbon, and ash content ofcoal and coke are important parameters. The “ranking” of coalincreases with increasing carbon content and decreasing vola-ti

19、le and hydrocarbon, (medium volatility) content.6. Interferences6.1 This test method depends upon distinctive thermostabil-ity ranges of the determined components as a principle of thetest. For this reason, materials which have no well-definedthermostable range, or whose thermostabilities are the sa

20、me asother components, may create interferences. Particular ex-amples include the following:6.1.1 Oil-filled elastomers have such high molecular weightoils and such low molecular weight polymer content that the oiland polymer may not be separated based upon temperaturestability.6.1.2 Ash content mat

21、erials (metals) are slowly oxidized athigh temperatures and in an air atmosphere, so that their massincreases (or decreases) with time. Under such conditions, aspecific temperature or time region must be identified for themeasurement of that component.6.1.3 Polymers, especially neoprene and acryloni

22、trile buta-diene rubber (NBR), carbonize to a considerable extent, givinglow values for the polymer and high values for the carbon.Approximate corrections can be made for this if the type ofpolymer is known.6.1.4 Certain pigments used in rubber lose weight onheating. For example, some pigments exhib

23、it water loss in therange 500 to 600C, resulting in high polymer values. Others,such as calcium carbonate, release carbon dioxide (CO2) upondecomposition at 825C, that may result in high carbon values.The extent of interference is dependent upon the type andquantity of pigment present.7. Apparatus7.

24、1 The essential equipment required to provide the mini-mum thermogravimetric analyzer capability for this testmethod includes:7.1.1 A thermobalance, composed of (1) a furnace toprovide uniform controlled heating or a specimen to a constanttemperature or at a constant rate within the 25 to 1000Ctempe

25、rature range of this test method; (2) a temperature sensorto provide an indication of the specimen/furnace temperature to61C; (3) an electrobalance to continuously measure thespecimen mass with a minimum capacity of 30 mg and asensitivity of 61 g; and (4) a means of sustaining thespecimen/container

26、under atmosphere control with a purge rateof 10 to 100 6 5 mL/min.7.1.2 A temperature controller, capable of executing aspecific temperature program by operating the furnace betweenselected temperature limits at a rate of temperature changebetween 10 and 100C/min constant to within 61 % for aminimum

27、 of 100 min.7.1.3 A data collection device, to provide a means ofacquiring, storing, and displaying measured or calculatedsignals, or both. The minimum output signals required forThermogravimetric analyzers are mass, temperature, and time.NOTE 1The capability to display the first derivative of the s

28、ignal maybe useful in the measurement of obscure thermostability ranges.7.1.4 Containers (pans, crucibles, and so forth), which areinert to the specimen and which will remain dimensionallystable within the temperature limits of this test method.7.2 Gas flow dontrol device, with the capability of swi

29、tchingbetween inert and reactive gases.8. Reagents and Materials8.1 An inert compressed gas such as argon or nitrogen anda reactive compressed gas such as air or oxygen are requiredfor this test method.8.2 Purity of Purge Gases:8.2.1 0.01 % maximum total impurity.8.2.2 1.0 g/g water impurity maximum

30、.8.2.3 1.0 g/g hydrocarbon impurity maximum.8.2.4 The inert purge gas must not contain more than 10g/g oxygen.9. Test Specimen9.1 Specimens are ordinarily measured as received. If someheat or mechanical treatment is applied to the specimen prior totest, this treatment shall be noted in the report.9.

31、2 Since the applicable samples may be mixtures or blends,take care to ensure that the analyzed specimen is representativeof the sample from which it is taken. If the sample is a liquid,mixing prior to taking the specimen is sufficient to ensure thisconsideration. If the sample is a solid, take sever

32、al specimensfrom different areas of the sample and either combine for asingle determination, or each run separately with the finalanalysis representing an average of the determinations. Notethe number of determinations in the report.10. Calibration10.1 Calibrate the mass signal from the apparatus ac

33、cordingto Test Method E2040.10.2 Calibrate the temperature signal from the apparatusaccording to Practice E1582.E1131 08 (2014)211. Procedure11.1 Establish the inert (nitrogen) and reactive (air oroxygen) gases at the desired flow rates. For most analyses, thisrate will be in the range of 10 to 100

34、mL/min. Higher flow ratesmay be used for some analyses, particularly when utilizinghigh heating rates.11.2 Switch the purge gas to the inert (nitrogen) gas.11.3 Zero the mass signal r and tare the balance.11.4 Open the apparatus to expose the specimen holder.11.5 Prepare the specimen as outlined in

35、9.2 and carefullyplace it in the specimen holder. Typically, a sample mass of 10to 30 mg shall be used (see Table 1).NOTE 2Specimens smaller than 10 mg may be used if largerspecimens cause instrument fouling or poor reproducibility.11.6 Position the specimen temperature sensor to the samelocation us

36、ed in calibration. (See Section 10.)11.7 Enclose the specimen holder.11.8 Record the initial mass. If the apparatus in use hasprovisions for direct percentage measurements, adjust to read100 %.11.9 Initiate the heating program within the desired tem-perature range. See Table 1 for suggested heating

37、rates andtemperature ranges. Record the specimen mass change con-tinuously over the temperature interval.11.9.1 The mass loss profile may be expressed in eithermilligrams or mass percent of original specimen mass. Ex-panded scale operation may be useful over selected tempera-ture ranges.11.9.2 If on

38、ly one or two components of the compositionalanalysis are desired, specific, more limited temperature rangesmay be used. Similarly, several heating rates may be usedduring analysis in those regions of greater or lesser interest.Isothermal periods may be necessary for some materials. SeeTable 1 for s

39、uggested parameters.11.10 Once a mass loss plateau is established in the range600 to 950C, depending on the material, switch from inert toreactive (air or oxygen) environment.11.10.1 If a distinct plateau is not observed in this range, theatmosphere change is made based on the zero slope indicationo

40、f the recorded first derivative or upon some agreed upontemperature. Suggested temperatures for this region are givenin Table 1.11.10.2 The resolution of this region may be enhanced,where carbon is present in large quantities or of special interest,by maintaining the specimen at constant temperature

41、 forseveral minutes after switching environments.11.11 The analysis is complete upon the establishment of amass loss plateau following the introduction of the reactivegas.11.12 Switch to the inert purge gas.11.13 Calculate and report the sample composition.12. Calculation12.1 Highly volatile matter

42、is represented by a mass lossmeasured between the starting temperature and Temperature X(see Fig. 1). Temperature X should be taken in the center of thefirst mass loss plateau or, if no resolvable plateau exists, at anagreed upon temperature value. Suggested values for Tempera-ture X are given in Ta

43、ble 2.12.1.1 Highly volatile matter content may be determined bythe following equation:V 5W 2 RW3100% (1)where:V = highly volatile matter content, as received basis (%),W = original specimen mass (mg), andR = mass measured at Temperature X (mg).12.2 Medium volatile matter is represented by the mass

44、lossmeasured from Temperature X to Temperature Y (see Fig. 1).Temperature Y should correspond to the mass loss plateau usedfor switching atmospheres.12.2.1 Medium volatile matter content can be determinedusing the following equation:O 5R 2 SW3100% (2)where:O = medium volatile matter content, as-rece

45、ived basis, %,R = mass measured at Temperature X, (mg),S = mass measured at Temperature Y, (mg), andW = original specimen mass, (mg).12.3 Combustible material content is represented by themass loss measured from Temperature Y to Temperature Z (seeFig. 1). This region corresponds to the mass loss as

46、a result ofthe oxidation of carbon to carbon dioxide.12.3.1 Combustible material content may be calculated bythe following equation:C 5S 2 TW3100% (3)TABLE 1 Suggested Compositional Analysis ParametersMaterialSampleSize mgFlow RatemL/minAPurgeTimeMinTemperatureHeatingRateC/minGasSwitchoverCInitial X

47、 Y ZBcoal 20 50 5 ambient 110 900 900 10 to 150 900elastomers 20 50 2 ambient 325 550 750 10 600thermoplastics 20 50 2 ambient 200 600 750 10 600lubricants 20 40 to 500 1 50 150 600 750 10 to 100 600thermosets 20 50 2 ambient 200 550 750 10 600AMay differ depending upon instrument design.BZ is not n

48、ecessarily the final temperature.E1131 08 (2014)3where:C = combustible material content, as-received basis, (%),S = mass measured at Temperature Y, (mg),T = mass measured at Temperature Z, (mg) andW = original specimen mass, (mg).12.4 The residual weight remaining after the evolution ofcarbon dioxid

49、e is taken as ash content. This component ismeasured at Temperature Z. This temperature is not necessarilythe final temperature. Suggested values for Temperature Z aregiven in Table 1.12.4.1 The ash components of some materials may slowlyoxidize and subsequently gain or lose weight at high tempera-tures. In such materials, a value for Temperature Z must bechosen prior to such transitions.12.4.2 The ash content may be calculated using the follow-ing equation:A 5TW3100% (4)where:A = ash content, as received basis, (%),T = mass measured at Temperature Z, (mg)