1、Designation: D4419 90 (Reapproved 2010)Standard Test Method forMeasurement of Transition Temperatures of PetroleumWaxes by Differential Scanning Calorimetry (DSC)1This standard is issued under the fixed designation D4419; the number immediately following the designation indicates the year oforiginal
2、 adoption or, in the 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.1. Scope1.1 This test method covers the transition temperatures ofpetroleum wax
3、es, including microcrystalline waxes, by differ-ential scanning calorimetry (DSC). These transitions mayoccur as a solid-solid transition or as a solid-liquid transition.1.2 The normal operating temperature range extends from15C to 150C (Note 1).1.3 The values stated in SI units are to be regarded a
4、s thestandard.1.4 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
5、. Referenced Documents2.1 ASTM Standards:2D87 Test Method for Melting Point of Petroleum Wax(Cooling Curve)D1160 Test Method for Distillation of Petroleum Productsat Reduced Pressure3D3418 Test Method for Transition Temperatures and En-thalpies of Fusion and Crystallization of Polymers byDifferentia
6、l Scanning CalorimetryE472 Practice for Reporting Thermoanalytical Data3E473 Terminology Relating to Thermal Analysis and Rhe-ologyE474 Method for Evaluation of Temperature Scale forDifferential Thermal Analysis33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 Differential Scan
7、ning Calorimetry (DSC)A tech-nique in which the difference in energy inputs into a substanceand a reference material is measured as a function of tempera-ture, while the substance and a reference material are subjectedto a controlled temperature program. The record is the DSCcurve. Two modes, power-
8、compensation DSC and heat-fluxDSC, can be distinguished depending on the method ofmeasurement used. For additional background informationrefer to Practice E472, Terminology E473, and Test MethodE474.4. Summary of Test Method4.1 Separate samples of petroleum wax and a referencematerial or blank (empt
9、y sample container) are heated at acontrolled rate in an inert atmosphere. A sensor continuouslymonitors the difference in heat flow to the two samples. TheDSC curve is a record of this difference versus temperature. Atransition in the wax involves the absorption of energy relativeto the reference,
10、resulting in an endothermic peak in the DSCcurve. While the transition occurs over the temperature rangespanned by the base of the peak, the temperature associatedwith the peak apex is designated the nominal transitiontemperature (Note 1).NOTE 1Test Method D87 also monitors energy transfer between w
11、axand a standard environment. The highest temperature DSC transition maydiffer from the melting point because the two methods approach thesolid/liquid phase transition from different directions.5. Significance and Use5.1 DSC in a convenient and rapid method for determiningthe temperature limits with
12、in which a wax undergoes duringtransitions. The highest temperature transition is a solid-liquidtransition associated with complete melting; it can guide thechoice of wax storage and application temperatures. Thesolid-solid temperature transition is related to the properties ofthe solid, that is, ha
13、rdness and blocking temperature.NOTE 2For a relatively narrow cut petroleum wax, the lowesttransition will be a solid-solid transition.Anarrow cut wax is one obtainedby deoiling a single petroleum distillate with a maximum range of 120Fbetween its 5 % and 95 % vol in accordance with Test Method D116
14、0boiling points (converted to 760 torr). The DSC method cannot differen-tiate between solid-liquid and solid-solid transitions. Such information1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.10
15、.0A on Physical/Chemical Properties.Current edition approved May 1, 2010. Published May 2010. Originallyapproved in 1984. Last previous edition approved in 2005 as D4419 90 (2005).DOI: 10.1520/D4419-90R10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer S
16、ervice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box
17、C700, West Conshohocken, PA 19428-2959, United States.must be predetermined by other techniques. In the case of blends, thelower temperature transition may be envelopes of both solid-liquid andsolid-solid transitions.5.2 Since petroleum wax is a mixture of hydrocarbons withdifferent molecular weight
18、s, its transitions occur over a tem-perature range. This range is one factor that influences thewidth, expressed in C, of the DSC peaks. The highesttemperature transition is a first-order transition. If, for a seriesof waxes, there is supporting evidence that the highest tem-perature transition of e
19、ach wax is the major first-order transi-tion, its relative width should correlate with the relative widthof the waxs molecular weight distribution.6. Interferences6.1 The test specimen must be homogeneous and represen-tative. The small sample size (10 mg) makes these require-ments particularly impor
20、tant.6.2 Intimate thermal contact, sample-to-pan and pan-to-sensor, is essential to obtain accurate and reproducible results.6.3 The heating rate must be the specified 10 6 1C/min.Faster or slower rates will produce a different transitiontemperature and transition peak width.7. Apparatus7.1 Differen
21、tial Scanning Calorimeter, operating in eitherpower compensation or heat flux mode, capable of heating at10 6 1C/min from 15C to 150C. Controlled coolingcapability is preferred but not essential. The calorimeter mustbe able to record automatically the differential signal (WE orWT) versus temperature
22、 with a temperature repeatability of60.5C. If the differential record is versus time, the calorim-eter must have the capability to make a simultaneous record oftemperature versus time.7.2 Sample Pans, of aluminum or other metal of highthermal conductivity, excluding copper and its alloys.7.3 Referen
23、ce MaterialGlass beads, alumina powder, sili-con carbide, or any material known to be unaffected byrepeated heating and cooling and free from interfering transi-tions. The specific heat capacity of the reference should be asclose as possible to that of the test material.7.4 Recorder, capable of reco
24、rding heat flow versus tem-perature.8. Reagent8.1 Nitrogen, or other dry inert gas supply for flushing thesample compartment.9. Calibration9.1 Using the instrument manufacturers recommended pro-cedure, calibrate the instruments temperature scale over thetemperature range of interest with appropriate
25、 standards. Theseinclude, but are not limited to:Melting PointStandard 99 % Purity Min. C KPhenoxybenzene (2)426.9 300.0p-Nitrotoluene (3) 51.5 324.8Naphthalene (4) 80.3 353.6Benzoic AcidA122.4 395.7Adipic Acid (5) 153.0 426.3Indium Metal (2) 156.6 429.9ASee Test Method D3418. 99.98 % purity availab
26、le from U.S. Bureau ofStandards as SRM 350.9.2 The specimen weight and test procedure should be thosespecified in Section 10, except that the precycle (11.3)isomitted.10. Specimen Preparation10.1 To ensure homogeneity, completely melt the entiresample by heating it to 10C above the temperature at wh
27、ichthe wax is completely molten. Using a clean eyedropper,transfer a few drops to the surface of a clean sheet of aluminumfoil to form a thin wax film. Separate the wax from the foil, andbreak it into pieces.11. Procedure11.1 Weigh 10 6 1 mg of the wax pieces into a sample pan,and insert the pan in
28、the calorimeter sample compartment.NOTE 3Intimate thermal contact, sample-to-pan and pan-to-sensor, isessential. Ensure that pan bottoms are flat and also that sensor surfaceswhere pans rest are clean. If the equipment is available, it is advantageousto ensure maximum sample-to-pan thermal contact b
29、y crimping a metalcover against the pan with the sample sandwiched in between. A thermalprecycle (see section 10.3 ) improves pan contact and establishes the samethermal history for every sample.11.2 Flush the sample compartment of the test cell with inertgas throughout the test; a flow of 10 to 50
30、mL/min is typical.11.3 Perform a thermal precycle (Note 3). Heat the test cellat 10 6 1C/min to 20 6 5C beyond the end of melting,beyond the return to the base line (Note 4 and Note 5). Thencool the test cell to 15 6 5C at 10 6 1C/min. Hold the testcell at 15C for 30 s.NOTE 4During the precycle heat
31、ing scan, note the height of the firstthermo transition peak, and adjust instrument sensitivity so it is 50 to 95 %of full scale.NOTE 5The exposure of the sample to high temperatures should beminimized to prevent decomposition. Hold the maximum temperatureonly for the time required to prepare for co
32、oling.11.4 Perform and record the thermal scan of record. Heatthe test cell at 10 6 1C/min to 20 6 5C beyond the end ofmelting (Note 6). Record the DSC curve using a heating rate of10 6 1C/min from 15C to 20 6 5C beyond the end ofmelting.NOTE 6A cooling (solidification) scan is also possible, but th
33、etransition peak apex will be several degrees Celsius lower than thatobtained using a heating scan.12. Calculation12.1 Several transitions may be present. Number themconsecutively in order of appearance. Draw tangents to eachtransition peak (see Fig. 1). The transition peak apex (TA)islocated by the
34、 intersection of the tangents to the peak slopes(Note 7 and Note 8).NOTE 7The extrapolated onset (TO) and end (TE) temperatures arelocated by the intersection of the peak tangents with the base line (see Fig.4The boldface numbers in parentheses refer to the list of references at the end ofthis test
35、method.D4419 90 (2010)21). The difference between the onset and end temperatures of eachtransition peak is a measure of peak width.NOTE 8Some microcrystalline waxes may exhibit shoulders on thetransition peaks. If this occurs, exclude the shoulder in drawing in theextrapolated onset (TO) and end (TE
36、) temperatures.12.2 Read the temperature associated with each transitionpeak apex from the curve, and apply any correction indicatedby the temperature-scale calibration.13. Report13.1 Report the corrected apex and end temperatures foreach of the transition peaks to the nearest 0.5C in order ofoccurr
37、ence. First thermal transition apex (T1A), first thermaltransition end temperature (T1E), second thermal transiton apextemperature (T2A), and second thermal transition end tempera-ture (T2E), transition temperature of petroleum waxes by DSC.14. Precision and Bias14.1 PrecisionThe precision of this t
38、est method as ob-tained by statistical examination of interlaboratory test resultsis as follows:14.1.1 RepeatabilityThe difference between successivetest results, obtained by the same operator with the sameapparatus under constant operating conditions on identical testmaterial, would, in the long ru
39、n, in the normal and correctoperation of the test method, exceed the following values onlyin one case in twenty:C FSolid-Liquid Transition TemperaturesApex, T2AEnd, T2E0.81.0(1.4)(1.8)Solid-Solid Transition TemperaturesApex, T1AEnd, T1E1.21.4(2.2)(2.5)14.1.2 ReproducibilityThe difference between two
40、 singleand independent results, obtained by different operators work-ing in different laboratories on identical test material, would, inthe long run, in the normal and correct operation of the testmethod, exceed the following values only in one case intwenty:C FSolid-Liquid Transition TemperaturesAp
41、ex, T2AEnd, T2E3.56.1(6.3)(11.0)Solid-Solid Transition TemperaturesApex, T1AEnd, T1E2.311.2(4.1)(20.2)NOTE 9DSC will not differentiate between solid-liquid and solid-solid transitions; other techniques must be used for example, melting pointin accordance with Test Method D87.14.1.3 The first thermal
42、 transition temperature precisiondata are based on duplication determinations on five differentpetroleum waxes in an interlaboratory study among six labo-ratories. The second thermal transition temperature precisiondata are based on duplicate determinations on two differentpetroleum waxes in an inte
43、rlaboratory study among six labo-ratories.14.2 BiasThe procedure in this test method has no biasbecause the value of transition temperatures can be definedonly in terms of a test method.15. Keywords15.1 differential scanning calorimetry; petroleum wax; ther-mal properties; transition temperatureASam
44、ple determined to have solid-liquid and solid-solid transitions by anothertechnique.FIG. 1 Schematic of Petroleum WaxADSC Curve(Heating Cycle)D4419 90 (2010)3REFERENCES(1) Mackenzie, R. C.,“Nomenclature in Thermal Analysis, Part IV,”Journal of Thermal Analysis, 13, 1978, p. 387.(2) Rossini, F. D., P
45、ure Applied Chemistry, Vol 22, 1970, p. 557.(3) Timmermans and Hennant-Roland, J. Chim. Physics, Vol 34, 1937, p.693.(4) API Project 44, Vol I, Tables 23-2-(33.5200)A and AE.(5) Morrison, J. D. and Robertson, J. M. J. Chem. Soc. London, 1949, p.987.ASTM International takes no position respecting the
46、 validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is
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48、dquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This st
49、andard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D4419 90 (2010)4
