ASTM E1131-2008 Standard Test Method for Compositional Analysis by Thermogravimetry《用热重力法进行成分分析的标准试验方法》.pdf

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1、Designation: E 1131 08Standard Test Method forCompositional Analysis by Thermogravimetry1This standard is issued under the fixed designation E 1131; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe

2、r 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 matter, medium volat

3、ile 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 room tempera-tu

4、re to 1000 C. 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.1.6 This stand

5、ard 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 the applica-bil

6、ity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 3172 Practice for Proximate Analysis of Coal and CokeE 473 Terminology Relating to Thermal Analysis and Rhe-ologyE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE

7、1142 Terminology Relating to Thermophysical PropertiesE 1582 Practice for Calibration of Temperature Scale forThermogravimetryE 2040 Test Method for Mass Scale Calibration of Thermo-gravimetric Analyzers2.2 ISO Standard:11358 Plastics-Thermogravimetry (TG) of Polymers General Principles33. Terminolo

8、gy3.1 Definitions:3.1.1 Many of the technical terms used in this test methodare defined in Terminologies E 473 and E 1142.3.2 Definitions of Terms Specific to This Standard:3.2.1 highly volatile mattermoisture, plasticizer, residualsolvent or other low boiling (200 C or less) components.3.2.2 medium

9、 volatile mattermedium volatility materialssuch as oil and polymer degradation products. In general, thesematerials degrade or volatilize in the temperature range 200 to750 C.3.2.3 combustible materialoxidizable material not vola-tile (in the unoxidized form) at 750 C, or some stipulatedtemperature

10、dependent on material. Carbon is an example ofsuch a material.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.4. Summar

11、y 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 atmosphere p

12、rovide 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 acompositional analysis is desired or a comparison can be madewith a known material of the same type.5.2 The param

13、eters described should be considered asguidelines. They may be altered to suit a particular analysis,provided the changes are noted in the report.1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on Thermal

14、Test Methods and Practices.Current edition approved Sept. 1, 2008. Published October 2008. Originallyapproved in 1986. Last previous edition approved in 2003 as E 1131 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Ann

15、ual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Supporting data available from ASTM. Request RR: E371009.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3 The proportio

16、n of the determined components in a givenmixture or blend may indicate specific quality or end useperformance characteristics. Particular examples include thefollowing:5.3.1 Increasing soot (carbon) content of used diesel lubri-cating oils indicates decreasing effectiveness.5.3.2 Specific carbon-to-

17、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 requirespecific inert content (for example, ash, filler, reinforcingagent, etc.) to meet performance specifications.5

18、.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-tile and hydrocarbon, (medium volatility) content.6. Interferences6.1 This test method depends upon distinctive thermost

19、abil-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 same asother components, may create interferences. Particular ex-amples include the following:6.1.1 Oil-filled elastomer

20、s 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 materials (metals) are slowly oxidized athigh temperatures and in an air atmosphere, so that their massincreases (or decr

21、eases) 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 acrylonitrile buta-diene rubber (NBR), carbonize to a considerable extent, givinglow values for the polymer and high values fo

22、r 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 exhibit water loss in therange 500 to 600 C, resulting in high polymer values. Others,such as calcium carbonate, release CO

23、2upon decomposition at825 C, that may result in high carbon values. The extent ofinterference is dependent upon the type and quantity ofpigment present.7. Apparatus7.1 The essential equipment required to provide the mini-mum thermogravimetric analyzer capability for this methodincludes:7.1.1 A therm

24、obalance, composed of (a) a furnace toprovide uniform controlled heating or a specimen to a constanttemperature or at a constant rate within the 25 to 1000 Ctemperature range of this test method; (b) a temperature sensorto provide an indication of the specimen/furnace temperature to61C; (c) an elect

25、robalance to continuously measure thespecimen mass with a minimum capacity of 30 mg and asensitivity of 61 g; and (d) a means of sustaining thespecimen/container under atmosphere control with a purge rateof 10 to 100 6 5 mL/min.7.1.2 A temperature controller, capable of executing aspecific temperatu

26、re program by operating the furnace betweenselected temperature limits at a rate of temperature changebetween 10 and 100 C/min constant to within 61 % for aminimum of 100 min.7.1.3 A data collection device, to provide a means ofacquiring, storing, and displaying measured or calculatedsignals, or bot

27、h. The minimum output signals required forThermogravimetric analyzers are mass, temperature, and time.NOTE 1The capability to display the first derivative of the signal maybe useful in the measurement of obscure thermostability ranges.7.1.4 Containers (pans, crucibles, and so forth), which areinert

28、to the specimen and which will remain dimensionallystable within the temperature limits of this method.7.2 Gas Flow Control Device, with the capability of switch-ing between inert and reactive gases.8. Reagents and Materials8.1 An inert compressed gas such as argon or nitrogen anda reactive compress

29、ed gas such as air or oxygen are requiredfor this 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.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 o

30、rdinarily measured as received. If someheat or mechanical treatment is applied to the specimen prior totest, 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 representativeof the sample from which

31、 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 several specimensfrom different areas of the sample and either combine for asingle determination, or each run separately with the finalanalysis repres

32、enting an average of the determinations. Notethe number of determinations in the report.10. Calibration10.1 Calibrate the mass signal from the apparatus accordingto Test Method E 2040.10.2 Calibrate the temperature signal from the apparatusaccording to Practice E 1582.11. Procedure11.1 Establish the

33、 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 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.

34、3 Zero the mass signal r and tare the balance.E113108211.4 Open the apparatus to expose the specimen holder.11.5 Prepare the specimen as outlined in 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

35、 may be used if largerspecimens cause instrument fouling or poor reproducibility.11.6 Position the specimen temperature sensor to the samelocation used 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 per

36、centage measurements, adjust to read100 %.11.9 Initiate the heating program within the desired tem-perature range. See Table 1 for suggested heating rates andtemperature ranges. Record the specimen mass change con-tinuously over the temperature interval.11.9.1 The mass loss profile may be expressed

37、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 only one or two components of the compositionalanalysis are desired, specific, more limited temperature rangesmay be used. Similarly, several heating rat

38、es may be usedduring analysis in those regions of greater or lesser interest.Isothermal periods may be necessary for some materials. SeeTable 1 for suggested parameters.11.10 Once a mass loss plateau is established in the range600 to 950 C, depending on the material, switch from inert toreactive (ai

39、r 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 indicationof the recorded first derivative or upon some agreed upontemperature. Suggested temperatures for this region are givenin Table 1.11.10.2 The resolution

40、 of this region may be enhanced,where carbon is present in large quantities or of special interest,by maintaining the specimen at constant temperature forseveral minutes after switching environments.11.11 The analysis is complete upon the establishment of amass loss plateau following the introductio

41、n 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 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 t

42、hefirst mass loss plateau or, if no resolvable plateau exists, at anagreed upon temperature value. Suggested values for Tempera-ture X are given in Table 2.12.1.1 Highly volatile matter content may be determined bythe following equation:V 5W RW3 100 % (1)where:V = highly volatile matter content, as

43、received basis (%),W = original specimen mass (mg), andR = mass measured at Temperature X (mg).12.2 Medium volatile matter is represented by the mass lossmeasured from Temperature X to Temperature Y (see Fig. 1).Temperature Y should correspond to the mass loss plateau usedfor switching atmospheres.1

44、2.2.1 Medium volatile matter content can be determinedusing the following equation:O 5R SW3 100 % (2)where:O = medium volatile matter content, as-received basis, %,R = mass measured at Temperature X, (mg),S = mass measured at Temperature Y, (mg), andW = original specimen mass, (mg).12.3 Combustible

45、material content is represented by themass loss measured from Temperature Y to Temperature Z (seeFig. 1). This region corresponds to the mass loss as a result ofthe oxidation of carbon to carbon dioxide.12.3.1 Combustible material content may be calculated bythe following equation:C 5S TW3 100 % (3)

46、where: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 dioxide is taken as ash content. This component isTABLE

47、 1 Suggested Compositional Analysis ParametersMaterialSampleSize mgFlow RatemL/minAPurgeTimeMinTemperatureHeatingRateC/minGasSwitchoverCInitial X 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

48、 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 necessarily the final temperature.E1131083measured at Temperature Z. This temperature is not necessarilythe final temperature. Suggested values for Temperat

49、ure 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 5TW3 100 % (4)where:A = ash content, as received basis, (%),T = mass measured at Temperature Z, (mg) andW = original specimen mass.NOTE 3The use of the recorded first derivative may be useful inlocating the value of X, Y, and Z by examining areas of t