1、Designation: D 4419 90 (Reapproved 2005)An American National StandardStandard Test Method forMeasurement of Transition Temperatures of PetroleumWaxes by Differential Scanning Calorimetry (DSC)1This standard is issued under the fixed designation D 4419; the number immediately following the designatio
2、n indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number 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 covers the transit
3、ion temperatures ofpetroleum waxes, 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
4、in SI units are to be regarded as 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 regul
5、atory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D87 Test Method for Melting Point of Petroleum Wax(Cooling Curve)D 1160 Test Method for Distillation of Petroleum Productsat Reduced PressuresD 3418 Test Method for Transition Temperatures of Poly-mers by Differential Scanning
6、 CalorimetryE 472 Practice for Reporting Thermoanalytical Data3E 473 Terminology Relating to Thermal AnalysisE 474 Test Method for Evaluation of Temperature Scale forDifferential Thermal Analysis33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 Differential Scanning Calorimetry
7、 (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-compensation DSC
8、 and heat-fluxDSC, can be distinguished depending on the method ofmeasurement used. For additional background informationrefer to Practice E 472, Terminology E 473, and Test MethodE 474.4. Summary of Test Method4.1 Separate samples of petroleum wax and a referencematerial or blank (empty sample cont
9、ainer) 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, resulting in
10、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 D87also monitors energy transfer between waxand a standa
11、rd 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 within which a wax
12、 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, hardness and blo
13、cking 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 D 1160boiling poin
14、ts (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 on Propertie
15、s of Petroleum Wax.Current edition approved May 1, 2005. Published May 2005. Originallyapproved in 1984. Last previous edition approved in 2000 as D 4419 90 (2000).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Boo
16、k of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.must be predetermined by other techniques. In the case of blends, thelo
17、wer temperature transition may be envelopes of both solid-liquid andsolid-solid transitions.5.2 Since petroleum wax is a mixture of hydrocarbons withdifferent molecular weights, its transitions occur over a tem-perature range. This range is one factor that influences thewidth, expressed in C, of the
18、 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 each wax is the major first-order transi-tion, its relative width should correlate with the relative widthof the waxs molecula
19、r 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 important.6.2 Intimate thermal contact, sample-to-pan and pan-to-sensor, is essential to obtain accurate and reproducible results.
20、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 Differential Scanning Calorimeter, operating in eitherpower compensation or heat flux mode, capable of heating at10 6 1C/min from 15C
21、 to 150C. Controlled coolingcapability is preferred but not essential. The calorimeter mustbe able to record automatically the differential signal (WE orWT) versus temperature with a temperature repeatability of60.5C. If the differential record is versus time, the calorim-eter must have the capabili
22、ty 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 Reference MaterialGlass beads, alumina powder, sili-con carbide, or any material known to be unaffected byrepeated heating and cooli
23、ng 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 recording heat flow versus tem-perature.8. Reagent8.1 Nitrogen, or other dry inert gas supply for flushing thesample compartment.
24、9. Calibration9.1 Using the instrument manufacturers recommended pro-cedure, calibrate the instruments temperature scale over thetemperature range of interest with appropriate standards. Theseinclude, but are not limited to:Melting PointStandard 99 % Purity Min. C KPhenoxybenzene (2)426.9 300.0p-Nit
25、rotoluene (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 D 3418. 99.98 % purity available from U.S. Bureau ofStandards as SRM 350.9.2 The specimen weight and test procedure should be thosespecified in Section 10
26、, 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 whichthe wax is completely molten. Using a clean eyedropper,transfer a few drops to the surface of a clean sheet of aluminumfo
27、il 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 the calorimeter sample compartment.NOTE 3Intimate thermal contact, sample-to-pan and pan-to-sensor, isessential. Ensure that
28、 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 by crimping a metalcover against the pan with the sample sandwiched in between. A thermalprecycle (see section 10.3 ) improve
29、s 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 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 me
30、lting,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 heating scan, note the height of the firstthermo transition peak, and adjust instrument sensitivity so it is 50 to 95 %of full s
31、cale.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 cooling.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 ofmelti
32、ng (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 thetransition peak apex will be several degrees Celsius lower than thatobtained using a heating scan.12. Calculation12.1 Sever
33、al 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 intersection of the tangents to the peak slopes(Note 7 and Note 8).NOTE 7The extrapolated onset (TO) and end (TE) temperatu
34、res 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 method.D 4419 90 (2005)21). The difference between the onset and end temperatures of eachtransition peak is a measure of pea
35、k 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) temperatures.12.2 Read the temperature associated with each transitionpeak apex from the curve, and apply any correction
36、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 ofoccurrence. First thermal transition apex (T1A), first thermaltransition end temperature (T1E), second thermal transiton apextemp
37、erature (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 test method as ob-tained by statistical examination of interlaboratory test resultsis as follows:14.1.1 RepeatabilityThe dif
38、ference between successivetest results, obtained by the same operator with the sameapparatus under constant operating conditions on identical testmaterial, would, in the long run, in the normal and correctoperation of the test method, exceed the following values onlyin one case in twenty:C FSolid-Li
39、quid 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 singleand independent results, obtained by different operators work-ing in different laboratories on identical test materi
40、al, 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 TemperaturesApex, T2AEnd, T2E3.56.1(6.3)(11.0)Solid-Solid Transition TemperaturesApex, T1AEnd, T1E2.311.2(4.1)(20.2)NOTE 9DSC will not di
41、fferentiate 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 transition temperature precisiondata are based on duplication determinations on five differentpetroleum waxes in an interl
42、aboratory study among six labo-ratories. The second thermal transition temperature precisiondata are based on duplicate determinations on two differentpetroleum waxes in an interlaboratory study among six labo-ratories.14.2 BiasThe procedure in this test method has no biasbecause the value of transi
43、tion temperatures can be definedonly in terms of a test method.15. Keywords15.1 differential scanning calorimetry; petroleum wax; ther-mal properties; transition temperatureASample determined to have solid-liquid and solid-solid transitions by anothertechnique.FIG. 1 Schematic of Petroleum WaxADSC C
44、urve(Heating Cycle)D 4419 90 (2005)3REFERENCES(1) Mackenzie, R. C., “Nomenclature in Thermal Analysis, Part IV,”Journal of Thermal Analysis, 13, 1978, p. 387.(2) Rossini, F. D., Pure Applied Chemistry, Vol 22, 1970, p. 557.(3) Timmermans and Hennant-Roland, J. Chim. Physics, Vol 34, 1937, p.693.(4)
45、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 validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are
46、 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 subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not r
47、evised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you
48、 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 standard 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).D 4419 90 (2005)4
