ASTM E1868-2004 Standard Test Method for Loss-On-Drying by Thermogravimetry《用热重量分析法测定干燥损耗的标准试验方法》.pdf

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1、Designation: E 1868 04Standard Test Method forLoss-On-Drying by Thermogravimetry1This standard is issued under the fixed designation E 1868; 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 par

2、entheses 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 describes a procedure for determiningthe amount of volatile matter of any kind that is driven off froma test specimen under a spec

3、ific set of temperature and timeconditions. This test method determines only the mass ofmaterial lost, not its identity.1.2 This test method is applicable to a wide variety of solidor liquid materials, mixtures or blends where the majorcomponent is stable at the test temperature.1.3 The applicable t

4、emperature range for this test method isgenerally between ambient temperature and 1000 C.1.4 Electronic instrumentation or automated data analysisand data reduction systems or treatments equivalent to thismethod may be used.NOTE 1Users are expressly advised that all such instruments ortechniques may

5、 not be equivalent. It is the responsibility of the user todetermine the necessary equivalency prior to use.1.5 SI units are the standard.1.6 There is no ISO method equivalent to this test standard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its u

6、se. 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. Referenced Documents2.1 ASTM Standards:2D 6 Test Method for Loss on Heating of Oil and AsphalticCompoundsD 1509 Te

7、st Method for Carbon BlackHeating LossD 2216 Test Method for Laboratory Determination of Water(Moisture) Content of Soil and RockD 2288 Test Method for Weight Loss of Plasticizers onHeatingD 2595 Test Method for Evaporation Loss of LubricatingGreases Over Wide-Temperature RangeD 2832 Guide for Deter

8、mining Volatile and NonvolatileContent of Paint and Related CoatingsD 3175 Test Method for Moisture in the Analysis Sample ofCoal and CokeD 4893 Test Method for Determination of Pitch VolatilityE 359 Test Method for Chemical Analysis of Soda Ash(Sodium Carbonate)E 473 Terminology Relating to Thermal

9、 AnalysisE 897 Test Method for Volatile Matter in the AnalysisSample of Refuse-Derived FuelE 1131 Test Method for Compositional Analysis by Ther-mogravimetryE 1142 Terminology Relating to Thermophysical PropertiesE 1582 Practice for Calibration of Temperature Scale forThermogravimetryE 1860 Test Met

10、hod for Elapsed Time Calibration of Ther-mal AnalyzersE 2040 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 in Terminology E 473 and Terminology E 1142.4. Summary of Test Method4.1

11、 A specimen of known mass is heated at a constanttemperature while its mass is continuously measured as afunction of time. At the end of a pre-determined time interval,or when the loss reaches a pre-determined rate, the mass loss ofthe specimen is recorded as a percent of the original mass. Thisvalu

12、e is identified as the loss-on-drying (LOD) value. TheLOD value is a function of both temperature and time.Therefore these values must be identified and reported. Atypical LOD value is reported as LOD = XX % (60 min at120 C).5. Significance and Use5.1 This test method is used to estimate the amount

13、ofvolatile materials present in a material.1This test method is under the jurisdiction of ASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on TestMethods.Current edition approved May 1, 2004. Published June 2004. Originallyapproved in 1997. Last previ

14、ous edition approved in 2002 as E 186802.2For 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 to the standards Document Summary page onthe ASTM website.1Copyright ASTM Inte

15、rnational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 This test method is useful for design purposes, serviceevaluation, regulatory statues, manufacturing control, qualitycontrol, specification acceptance, development and research.5.3 The results obtained

16、 by this test method may be equiva-lent to those obtained by other test methods and may be knownby other terms in their respective fields. Other tests and termsencountered include loss-on-heating (see Footnote3and TestMethods D 6, D 2288, and E 359), heating loss (see TestMethod D 1509), evaporative

17、 loss (see Test Method D 2595),volatile organic carbon, moisture or water (see Test MethodsD 2216 and D 3175), volatility (see Test Method D 4893),highly volatile matter (see Test Method E 897), and volatilecontent (see Guide D 2832).6. Interferences6.1 Because the specimen size is usually small, ca

18、re must betaken to ensure that each specimen is representative of thesample as a whole, or both.6.2 This test procedure measures total mass loss underspecific experimental conditions. If more than one volatilecomponent is present, the results will reflect the total of allthose volatile components pr

19、esent.6.3 If the test temperature is set too high, the resultantweight loss may include some decomposition of the matrixmaterial.7. Apparatus7.1 Thermogravimetric Analyzer, capable of continuouslyrecording specimen mass and temperature as a function of timeconsisting of:7.1.1 Electrobalance, with a

20、minimum specimen capacity of100 mg capable of continuously recording 10 g or smallermass changes. Performance may be verified in accordance withTest Method E 2040.7.1.2 Specimen Holders, that are inert to the specimen andof suitable structural shape and integrity to contain the 10 mgtest specimen us

21、ed in this test method. Specimen holders,composed of platinum, aluminum or quartz may be used, butother holders may be considered.7.1.3 Furnace, whose temperature can be controlled from25 to 1000C, capable of a heating rate of 5C/min and ofmaintaining a set temperature isothermally within that range

22、 to62 C.7.1.4 Specimen Atmosphere Control System, capable ofsupplying inert dry gas (usually purified grade nitrogen) withan operator selectable flow rate of 50 to 100 mL/min towithin6 5 mL/min.7.1.5 Measurement System, to continuously record speci-men temperature to within 60.1 C over the range fro

23、m 25 to1000 C.7.1.6 Timer, capable of continuously recording elapsed timeup to 20 h to within 60.1 min or 61 %, whichever is greater.Performance may be verified in accordance with Test MethodE 1860.7.1.7 Controller, capable of executing a temperature pro-gram by operating the furnace from 25 to 1000

24、 C at a rate of5 C/min to within 60.1 C/min and of maintaining a settemperature isothermally within the range of 62 C.7.1.8 Recording Device, to record and display the thermo-gravimetric thermal curve consisting of mass, and temperatureas a function of time to the specifications above.7.1.9 While no

25、t required, it is convenient to have a dataanalysis device that will continuously perform and display thefollowing calculation:7.1.9.1 Specimen mass as a percent of the initial mass.7.1.9.2 Specimen mass rate of change (in mass %/min)capable of detecting 0.01 %/min.7.1.10 While not required, it is c

26、onvenient to have anexperiment control device capable of terminating the experi-ment under the following conditions:7.1.10.1 When an operator selected period of time at anisothermal temperature condition has elapsed, and7.1.10.2 When an operator selected rate of mass loss isachieved.7.2 Gas Exhaust

27、System, capable of removing from thelaboratory the potentially noxious purge gas effluent of thesystem above.7.3 Inert GasPurified grade nitrogen.7.4 Micropipets or Syringes, for liquids, capable of dispens-ing up to 15 6 1 L.8. Hazards8.1 Toxic or corrosive effluent, or both, may be releasedwhen he

28、ating some materials and could be harmful to person-nel and to apparatus.9. Sampling9.1 Samples are usually analyzed on “as received” basis.Should some thermal or mechanical treatment (such as grind-ing, or sieving) be applied to the sample prior to analysis, itshall be indicated in the report. Grin

29、ding may release volatilesdue to the heating generated by grinding process.9.2 Since small test specimens are used, they must behomogeneous and representative of the sample. The mixing orstirring of samples prior to analysis is recommended wheneverpossible.10. Calibration10.1 Calibrate the temperatu

30、re signal from the apparatusaccording to Practice E 1582 using a heating rate of 1C/minand a transition temperature close to the isothermal testtemperature used in this procedure.10.2 Calibrate the mass signal from the apparatus accordingto Test Method E 2040.NOTE 2Regular analysis of performance st

31、andards (materials ofknown mass loss characteristics) where available,4serves as a check oninstrument status, operator efficiency, etc. and provides for a comparison3Formulary Vol XVII, United States Pharmacopoeia Convention, 12601 Twin-brook Parkway, Rockville, MD 20852.4Performance Standards for l

32、ow (2 %), medium (50 %) and high (99 %) LODvalues are available from Rose Consulting, 579 Kelly Avenue, Half Moon Bay, CA94019.E1868042of results from different laboratories. Verify mass measurement confor-mity to better than 1%. Verify time measurement conformity to better than1%.10.3 Calibrate the

33、 time signal from the apparatus accordingto Test Method E 186011. Procedure11.1 Cool the specimen test area of the apparatus to ambienttemperature. For the purpose of this test, ambient temperatureis 35 C or lower.NOTE 3Cooling of the specimen test area to 25 C following anexperiment is time consumi

34、ng on some apparatus. To improve productiv-ity, it is possible with some test samples to initiate the experiment at asomewhat higher temperature. This must be done with caution sincevolatility is a function of temperature. For highly volatile materials,appreciable portions of the test specimen mass

35、may be lost in experimentalset up, if initiated at too high of a temperature.11.2 With the apparatus closed in the normal operatingposition, tare the balance so that the empty sample panindicates zero mass.11.3 Open the apparatus to expose the specimen holder.11.4 Carefully place 10 6 1 mg of the te

36、st specimen on thespecimen holder. Other specimen sizes may be used but mustbe indicated in the report.11.5 Close the apparatus and record the initial mass as mi.Ifthe apparatus has provisions for direct recording of masspercent, adjust it to read 100 %.NOTE 4Should the test specimen have appreciabl

37、e volatility atambient temperature, it may lose a significant amount of mass as it isplaced into the test position. In such cases, care should be taken to perform11.4 and 11.5 as quickly as is practical.11.6 Heat the test specimen at 5 C/min to the isothermaltest temperature, while recording specime

38、n mass (or masspercent), temperature and elapsed time. Other heating ratesmay be used, but must be indicated in the report.NOTE 5Selection of the optimum operating parameters of isothermaltest temperature and test time (tt) is dependent on the class of materialsbeing tested. The technique of respons

39、e surface methodology (RSM) maybe useful in predicting optimum operating parameters.5,6Some commonexperimental conditions are presented in Tables 1 and 2.11.7 Once the test temperature is reached, it is isothermallyheld there for the remainder of the experiment. The time fromstart to the isothermal

40、portion of the experiment is taken as ti.11.8 After 5 min at the isothermal test temperature, thespecimen temperature is recorded.11.9 The experiment is terminated in one of two ways.These termination criteria are identified as Test Method A andTest Method B.11.10 Test Method A:11.10.1 After the tes

41、t specimen is held at the isothermal testtemperature for a fixed period of test time (tt).NOTE 6Commonly used isothermal test temperatures and times aretabulated in Table 1.11.10.1.1 Experiments terminated using Test Method Ashall indicate the termination conditions in parentheses follow-ing the LOD

42、 values. For example: LOD=XX%(2hat105 C).11.11 Test Method B:11.11.1 After a delay time (td) initiated when the mass lossrate becomes less than a specified value (R).NOTE 7Commonly used values for mass loss rate and delay time aretabulated in Table 2.NOTE 8For apparatus so equipped, the mass loss ra

43、te may beconveniently observed using the derivative of mass as a function of time.11.11.1.1 Experiments terminated using Test Method Bshall indicate the termination conditions in parentheses follow-ing the LOD values. For example: LOD=XX%(15 min at1 %/min).11.12 Record the mass at the time of the te

44、rmination of theexperiment. This value is the final mass, mf.11.13 Calculate the percent mass loss value according to Eq1 (see 12.1).11.14 Perform duplicate determinations and report the loss-on-drying value as the mean value of duplicate determinationsof percent mass loss.12. Calculation12.1 Calcul

45、ate percent mass loss according to the followingequation:m 5mi mf! 3 100 %mi(1)LOD 5 mean value of m for duplicate determinationswhere:5Multi Factor Experimental Designs for Exploring Response Surfaces, Box,G.E.P.; and Hunter, J. S.; Ann. Math. Stat., 28 195241 (1997).6“Estimation of Volatile Emissi

46、on Potential of Pesticides by ThermogravimetricAnalysis,” Pino, Judith A.; Barry, Terrell A.; and Rose, John E.; Proc. 110th Amer.Off. Anal Chem. Meeting, (1996).TABLE 1 Commonly Used Isothermal Test Temperatures andTimesMaterial Temperature, C Time, h Test MethodGrease 93 20 D 2595Barium Hydroxide

47、105 2ABarium Sulfate 105 4ACalcium Carbonate 200 4APesticides 65 11BRefuse Derived Fuel 950 0.1 E 897Pitch 360 0.5 D 4893Soil and Rock 110 12 D 2216Polymers 155 24 D 2288Carbon Black 125 1 D 1509Soda Ash 250 4 E 359Asphalt 163 5 D 6AFormulary Vol XVII, United States Pharmacopoeia Convention, 12601 T

48、win-brook Parkway, Rockville, MD 20852.BPino, J., Barry, T., and Rose, J., Estimation of Volatile Emission of Pesticides byThermogravimetric Analysis, California Environmental Protection Agency, 1020 NStreet, Room 161, Sacramento, CA 95814-5624.TABLE 2 Commonly Used Rates of Loss and Delay TimesMate

49、rialRate of Loss,%/minDelay Time,minReferencenoPesticides 0.1 15 2.2AAPino, J., Barry, T., and Rose, J., Estimation of Volatile Emission of Pesticides byThermogravimetric Analysis, California Environmental Protection Agency, 1020 NStreet, Room 161, Sacramento, CA 95814-5624.E1868043LOD = loss-on-drying (%),m = percent mass loss (%),mi= initial mass (mg), andmf= final mass (mg).NOTE 9Measured values should be entered into the equation retainingall decimal places. Only the final report value should be rounded inaccordance with the established precision o