1、Designation: E2009 08 (Reapproved 2014)1Standard Test Methods forOxidation Onset Temperature of Hydrocarbons byDifferential Scanning Calorimetry1This standard is issued under the fixed designation E2009; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEWarning notes were editorially updated throughout in March 2014.1. Scope1.1 These test metho
3、ds describe the determination of theoxidative properties of hydrocarbons by differential scanningcalorimetry or pressure differential scanning calorimetry underlinear heating rate conditions and are applicable tohydrocarbons, which oxidize exothermically in their analyzedform.1.2 Test Method AA diff
4、erential scanning calorimeter(DSC) is used at ambient pressure, of one atmosphere ofoxygen.1.3 Test Method BA pressure DSC (PDSC) is used at highpressure, for example, 3.5 MPa (500 psig) oxygen.1.4 Test Method CA differential scanning calorimeter(DSC) is used at ambient pressure of one atmosphere of
5、 air.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 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
6、 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D3350 Specification for Polyethylene Plastics Pipe and Fit-tings MaterialsD3895 Test Method for Oxidative-Induction Time of Poly-olefins by Dif
7、ferential Scanning CalorimetryD4565 Test Methods for Physical and Environmental Per-formance Properties of Insulations and Jackets for Tele-communications Wire and CableD5483 Test Method for Oxidation Induction Time of Lubri-cating Greases by Pressure Differential Scanning Calorim-etryE473 Terminolo
8、gy Relating to Thermal Analysis and Rhe-ologyE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE967 Test Method for Temperature Calibration of Differen-tial Scanning Calorimeters and Differential Thermal Ana-lyzersE1858 Test Method for Determining Oxidat
9、ion InductionTime of Hydrocarbons by Differential Scanning Calorim-etry3. Terminology3.1 DefinitionsFor definitions of terms used in these testmethods, refer to Terminology E473.3.1.1 oxidation (extrapolated) onset temperature (OOT)arelative measure of oxidative stability at the cited heating rateis
10、 determined from data recorded during a DSC scanningtemperature test. The temperature at which the onset to theobserved oxidation is taken as the OOT.4. Summary of Methods4.1 The test specimen in an aluminum container and anempty reference aluminum container or pan are heated at aspecified constant
11、heating rate in an oxygen (or air) environ-ment. Heat flow out of the specimen is monitored as a functionof temperature until the oxidative reaction is manifested byheat evolution on the thermal curve. The oxidation (extrapo-lated) onset temperature (OOT), a relative measure of oxida-tive stability
12、at the cited heating rate, is determined from datarecorded during the scanning temperature test. The OOTmeasurement is initiated upon reaching the exothermic reactionand measuring the extrapolated onset temperature.4.2 For some particularly stable materials, the OOT may bequite high (300C) at the sp
13、ecified heating rate of theexperiment. Under these circumstances, the OOT may be1These test methods are under the jurisdiction of ASTM Committee E37 onThermal Measurements and are the direct responsibility of Subcommittee E37.01 onCalorimetry and Mass Loss.Current edition approved March 15, 2014. Pu
14、blished April 2014. Originallyapproved in 1999. Last previous edition approved in 2008 as E2009 08. DOI:10.1520/E2009-08R14E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information
15、, refer 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 States1reduced by increasing the pressure of oxygen purge gas.Conversely, reducing the partial pressure of oxygen (such as byth
16、e use of air) may retard reactions that proceed too rapidly,with a corresponding increase of the OOT. By admixingoxygen gas with a suitable diluent, for example, nitrogen, theOOT will be increased (see Specification D3350 and TestMethods D3895, D4565, and D5483).NOTE 1For some systems, the use of co
17、pper pans to catalyzeoxidation will reduce the oxidation onset temperature. The results,however, will not necessarily correlate with non-catalyzed tests.5. Significance and Use5.1 Oxidation onset temperature is a relative measure of thedegree of oxidative stability of the material evaluated at a giv
18、enheating rate and oxidative environment, for example, oxygen;the higher the OOT value the more stable the material. TheOOT is described in Fig. 1. The OOT values can be used forcomparative purposes and are not an absolute measurement,like the oxidation induction time (OIT) at a constant tempera-tur
19、e (see Test Method E1858). The presence or effectiveness ofantioxidants may be determined by these test methods.5.2 Typical uses of these test methods include the oxidativestability of edible oils and fats (oxidative rancidity), lubricants,greases, and polyolefins.6. Apparatus6.1 Differential Scanni
20、ng Calorimeter (DSC) or PressureDifferential Scanning Calorimeter (PDSC)The essential in-strumentation required to provide the minimum differentialscanning calorimetric capability for these test methods in-cludes: a DSC chamber composed of a furnace to provideuniform controlled heating of a specimen
21、 and a reference to aconstant heating rate of at least 10C/min within the applicabletemperature range for these test methods; a temperature sensorto provide an indication of the specimen temperature to60.1C; a differential sensor to detect heat flow (power)difference between the specimen and the ref
22、erence to 0.1 mW;and the instrument should have the capability of measuringheat flow of at least 6 mW, with provision for less sensitiveranges.NOTE 2In certain cases when the sample under study is of highvolatility (for example, low molecular weight hydrocarbons), the use ofpressures in excess of 0.
23、1 MPa (1 atmosphere) is needed. The operator iscautioned to verify (with apparatus designer) the maximum oxygenpressure at which the apparatus may be safely operated. A PDSC is usedin Method B.6.2 A Data Collection Device, to provide a means ofacquiring, storing, and displaying measured or calculate
24、dsignals, or both. The minimum output signals required for DSCare heat flow, temperature and time.6.3 A high-pressure gas regulator or similar device to adjustthe applied pressure in the test chamber to less than 65%,including any temperature dependence on the transducer, isused in Method B. (Warnin
25、gUse metal free of organicmatter or fluoropolymer tubing with oxygen rather than thecommonly used rubber or polyvinyl chloride plastic tubing.There have been hazardous situations with prolonged use ofcertain polymer tubing in oxygen service.)NOTE 3Gas delivery tubing should be kept as short as possi
26、ble tominimize dead volume. The link between the test chamber and pressuretransducer should allow fast pressure equilibration to ensure accuraterecording of the pressure above the specimen during testing.6.4 Specimen containers are aluminum sample pans andshould be inert to the specimen and referenc
27、e material as wellas the oxidizing gas. The specimen containers should be ofsuitable structural shape and integrity to contain the specimenand reference in accordance with the specific requirements ofthese test methods, including a pressure system consisting of apressure vessel or similar means of s
28、ealing the test chamber atany applied pressure within the pressure limits required forthese test methods. The specimen containers shall be clean, dry,and flat. A typical cylindrical specimen container has thefollowing dimensions: height, 1.5 to 2.5 mm and outerdiameter, 5.0 to 7.0 mm.6.5 Flow meter
29、capable of reading 50 mL/min, or anotherselected flow rate, accurate to within 65 %. Ensure theflowmeter is calibrated for oxygen. Contact a supplier of flowmeters for specific details on calibration (see warning state-ment in 6.3).6.6 Use an analytical balance with a capacity of at least 100mg and
30、capable of weighing to the nearest 0.01 mg, or less than1 % of the specimen or containers masses, or both. Recom-mended procedure for new sample pan cleaning can be foundin Annex A1.7. Reagents and Materials7.1 Oxygen, extra dry, of not less than 99.5 % by volume.(WarningOxidizer. Gas under pressure
31、.)7.2 Air, extra dry.7.3 Indium, of not less than 99.9 % by mass.7.4 Tin, of not less than 99.9 % by mass.8. Sampling8.1 If the sample is a liquid or powder, mix thoroughly priorto sampling.8.2 In the absence of information, samples are to beanalyzed as received. If some heat or mechanical treatment
32、 isapplied to the sample prior to analysis, this treatment shall bein nitrogen and noted in the report. If some heat treatment isused prior to oxidative testing, then record any mass loss as aresult of the treatment.9. Precautions9.1 WarningOxygen is a strong oxidizer and vigorouslyaccelerates combu
33、stion. Keep surfaces clean.9.2 If the specimen is heated to decomposition, toxic orcorrosive products may be released.9.3 For certain types of PDSC, it is recommended that theflow be set up with a reverse flow implementation to ensurethere is no contact of decomposed hydrocarbons with incomingoxygen
34、 within the instrument. See instrument designers rec-ommendation on reverse flow.E2009 08 (2014)12FIG.1DSCOxidationOnsetTemperature(OOT),ExtrapolatedOnsetTemperatureE2009 08 (2014)139.4 Certain synthetic lubricants showed explosion-like onsetof oxidation. Aluminum containers were melted. Care must b
35、etaken to avoid damage to the sensor and cell.10. Calibration and Standardization10.1 Calibrate the temperature output of the instrumentusing Test Method E967, using a heating rate of 10C/min. Useindium and tin calibration material to bracket typical OOTsdetermined in these test methods. Calibration
36、 shall be per-formed under ambient pressure conditions.11. Procedure11.1 Weigh 3.00 to 3.30 mg of sample, to a precision of60.01 mg, into a clean specimen container. Do not place lid onspecimen pan or container.NOTE 4Other specimen sizes may be used if used consistently.However, the OOT values obtai
37、ned may differ from those obtained with a3 mg sample. Also, vented specimen covers may be used, but OOT valuesmay differ from those obtained in open containers. The followingprocedure assumes the use of open containers.11.2 Place the uncovered container with the prepared speci-men in the sample posi
38、tion of the instrument and an emptyspecimen container, without lid, in the reference position. Besure that the containers are centered on the sensors.11.3 Replace all covers in accordance with appropriatemanufactures recommendations.11.4 Adjust flow rate of oxygen gas at ambient pressure to50.0 (65)
39、 mL/min, accurate to 65%.NOTE 5Other flow rates may be used, but shall be noted in the report.Many flowmeters are not rated for high pressure operation and may burstif excess pressure is applied. In these cases, the flow rate should bemeasured at atmospheric pressure (0.1 MPa) at the exit of the DSC
40、 cell,if recommended by the instrument designer.11.5 Set the instrument sensitivity as required to retain theoxidation exotherm within the recorded range. A preanalysismay be required to determine this value.Asensitivity of 2 W/g,or less than 6 mW full scale, is typically acceptable.11.6 Purge the s
41、pecimen area for 3 to 5 min to ensureexchange of air with oxygen at atmospheric pressure. Checkthe flow rate at elevated pressure, and readjust to 50 6 5mL/min, if required.11.7 Commence programmed heating at 10C/min fromambient temperature to the onset of the exothermic heat flow.Record the heat fl
42、ow and sample temperature. The OOT ismeasured in oxygen from the baseline to the extrapolated onsettemperature of the exothermic process.11.8 Test Methods:11.8.1 When using DSC Test Method A, maintain a flowrate of 50 mL/min-1of oxygen at ambient pressure.11.8.2 When using PDSC Test Method B, pressu
43、rize slowly,adjust and maintain pressure of oxygen at 3.5 MPa (500 psig)6 0.2 MPa (25 psig), and maintain flow rate of 50 mL min-1.11.8.3 When using DSC Test Method C, maintain a flowrate of 50 mL min-1of air at ambient pressure.11.9 Continue the scanning DSC operation until the peak ofthe oxidation
44、 exotherm is observed or until an inflection pointis observed and the total displacement from the initial baselineexceeds 3 mW or 1 W/g.11.10 When the experiment is completed, cool the instru-ment to ambient temperature, 25C.NOTE 6When using Test Method B, allow the instrument to coolbefore releasin
45、g the pressure. Failure to do so may result in injury to theuser or damage to the instrument.11.11 OOT values less than 50C are not precise. OOTvalues greater than 300C can be expedited through the use ofa higher oxygen pressure.12. Calculation12.1 Determine the OOT, see Fig. 1.12.1.1 Extend the rec
46、orded temperature baseline beyond theoxidation reaction exotherm.12.1.2 Extrapolate the slope of the oxidation exotherm fromthe inflection point on the curve to the extended baseline.12.1.3 Determine the temperature at the intersection of12.1.1 and 12.1.2.12.1.4 The temperature at the intersection i
47、s the OOT.13. Report13.1 The report shall include the following:13.1.1 Description and identification of the sample, includ-ing any preparative treatment.13.1.2 Method used: A (DSC in oxygen), B (PDSC inoxygen), or C (DSC in air).13.1.3 Description of the apparatus, including commercialinstrument ma
48、ke and model, if applicable, and specimencontainer.13.1.4 Purge gas chemical composition and pressure.13.1.5 Purge gas flow rate, mL/min.13.1.6 OOT (61C) C.13.1.7 Specimen mass, mg.13.1.8 Any modifications or changes to listed conditions.13.1.9 The specific dated version of this method used.14. Prec
49、ision and Bias14.1 An interlaboratory test, using Method A, was con-ducted in 2001 involving participation by seven laboratoriesusing two instrument models from one manufacturer. Eachlaboratory characterized in hextuplicate a commercially avail-able polyethylene Oxidation Induction Time (OIT) referencematerial.3The results were evaluated using Practice E691. Theresults of this interlaboratory test are on file at ASTM Head-quarters.414.2 An interlaboratory test, using Method C, was con-ducted in 2001 involving participation by nine laboratoriesusing
