ASTM E1131-2003 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: E 1131 03Standard 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 (e) 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 vola

3、tile 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-t

4、ure 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 Computer or electronic-based instruments, techniques,or data treatment equivalent to this test method may also beused.NOTE 1Users of t

5、his test method are expressly advised that all suchinstruments or techniques may not be equivalent. It is the responsibility ofthe user of this test method to determine the necessary equivalency priorto use.1.6 SI units are the standard.1.7 This standard is related ISO 11358 but is more detailedand

6、specific.1.8 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-bility of regulatory limitations prior to use.2. Ref

7、erenced Documents2.1 ASTM Standards:D 3172 Practice for Proximate Analysis of Coal and Coke2E 473 Terminology Relating to Thermal Analysis3E 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3E 1142 Terminology Relating to Thermophysical Proper-ties3E 158

8、2 Practice for Calibration of Temperature Scale forThermogravimetry3E 2040 Test Method for Mass Scale Calibration of Thermo-gravimetric Analyzers42.2 ISO Standard:11358 Plastics-Thermogravimetry (TG) of Polymers General Principles53. Terminology3.1 Definitions:3.1.1 Many of the technical terms used

9、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 (200C or less) components.3.2.2 medium volatile mattermedium volatility materialssuch as oil and

10、 polymer degradation products. In general, thesematerials degrade or volatilize in the temperature range 200 to750C.3.2.3 combustible materialoxidizable material not vola-tile (in the unoxidized form) at 750C, or some stipulatedtemperature dependent on material. Carbon is an example ofsuch a materia

11、l.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. Summary of Test Method4.1 This test method is an empirical techniq

12、ue 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 provide acompositional analysis of that substance.5. Signific

13、ance 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 of ASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on ThermalAnalysis Methods.C

14、urrent edition approved March 10, 2003. Published April 2003. Originallyapproved in 1986. Last previous edition approved in 1998 as E 1131 98.2Annual Book of ASTM Standards, Vol 05.05.3Annual Book of ASTM Standards, Vol 14.02.4Available from American National Standards Institute, 11 W. 42nd St., 13t

15、hFloor, New York, NY 10036.5Supporting data available from ASTM. Request RR: 1009.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Spositional analysis is desired or a comparison can be madewith a known material of the same type.5.2 The para

16、meters described should be considered asguidelines. 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. Particula

17、r 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-polymer ratio ranges are requiredin some elastomeric and plastic parts in order to achievedesired mechanical strength and stability.5.3.

18、3 Some filled elastomeric and plastic products 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 in

19、creasing carbon content and decreasing vola-tile 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-definedthermostabl

20、e range, or whose thermostabilities are the same 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 u

21、pon temperaturestability.6.1.2 Ash content materials (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.

22、1.3 Polymers, especially neoprene and acrylonitrile 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 weig

23、ht onheating. For example, some pigments exhibit water loss in therange 500 to 600C, resulting in high polymer values. Others,such as calcium carbonate, release CO2upon decomposition at825C, that may result in high carbon values. The extent ofinterference is dependent upon the type and quantity ofpi

24、gment present.7. Apparatus7.1 The essential equipment required to provide the mini-mum thermogravimetric analyzer capability for this methodincludes:7.1.1 A thermobalance, composed of (a) a furnace toprovide uniform controlled heating or a specimen to a constanttemperature or at a constant rate with

25、in the 25 to 1000Ctemperature range of this test method; (b) a temperature sensorto provide an indication of the specimen/furnace temperature to61C; (c) an electrobalance to continuously measure thespecimen mass with a minimum capacity of 30 mg and asensitivity of 61 g; and (d) a means of sustaining

26、 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 temperature program by operating the furnace betweenselected temperature limits at a rate of temperature changebetween 10 and 100C/min constant to w

27、ithin 61 % for aminimum of 100 minutes.7.1.3 A recording device, capable of recording and display-ing the change in mass (TGA curve) on the Y-axis with aresolution of 5 g and temperature or time on the X-axis witha resolution of1Kor0.1min.NOTE 2The 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 method.7.2 Gas Flow Control Device, with the capability of switch-i

29、ng between 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 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

30、.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.9.2 Since

31、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 several speci

32、mensfrom 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 accordingt

33、o Test Method E 2040.10.2 Calibrate the temperature signal from the apparatusaccording to Practice E 1582.11. Procedure11.1 Establish the inert (nitrogen) and reactive (air oroxygen) gases at the desired flow rates. For most analyses, thisE1131032rate will be in the range of 10 to 100 mL/min. Higher

34、 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 recorder and tare the balance. It is recom-mended that this be done in a range at least one recorder settingmore sensitive than that to be used

35、in the final ash weighing.11.4 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 3Specimens smaller than 10 mg may be used if largerspecim

36、ens 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 percentage measurements, adjust

37、 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 in eithermilligrams or mass

38、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 rates may be usedduring analysi

39、s 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 950C, depending on the material, switch from inert toreactive (air or oxygen) environment.11.1

40、0.1 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 of this region may be enhanc

41、ed,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 introduction of the reactivegas.11.12 Sw

42、itch 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 thefirst mass loss plateau or,

43、 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 received basis (%),W = origin

44、al 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.12.2.1 Medium volatile matter

45、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 material content is represent

46、ed 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)where:C = combustible materia

47、l 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 1 Suggested Compositional An

48、alysis 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 20 40 to 500 1 50 150 600 75

49、0 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.E1131033measured 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