1、Designation: D4419 90 (Reapproved 2015)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 from15 C to 150 C (Note 1).1.3 The values stated in SI units are to be regarded
4、 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 regulatory limitations prior to use
5、.2. Referenced Documents2.1 ASTM Standards:2D87 Test Method for Melting Point of Petroleum Wax(Cooling Curve)D1160 Test Method for Distillation of Petroleum Products atReduced PressureD3418 Test Method for Transition Temperatures and En-thalpies of Fusion and Crystallization of Polymers byDifferenti
6、al Scanning CalorimetryE472 Practice for Reporting Thermoanalytical Data (With-drawn 1995)3E473 Terminology Relating to Thermal Analysis and Rhe-ologyE474 Method for Evaluation of Temperature Scale for Dif-ferential Thermal Analysis (Withdrawn 1986)33. Terminology3.1 Definitions of Terms Specific to
7、 This Standard:3.1.1 Differential Scanning Calorimetry (DSC)A tech-nique in which the difference in energy inputs into a substanceand a reference material is measured as a function oftemperature, while the substance and a reference material aresubjected to a controlled temperature program. The recor
8、d isthe DSC curve. Two modes, power-compensation DSC andheat-flux DSC, can be distinguished depending on the methodof measurement used. For additional background informationrefer to Practice E472, Terminology E473, and Test MethodE474.4. Summary of Test Method4.1 Separate samples of petroleum wax an
9、d a referencematerial or blank (empty 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
10、of energy relativeto the reference, 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 als
11、o monitors energy transfer between waxand 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 de
12、terminingthe temperature limits within 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
13、 properties ofthe solid, that is, hardness 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 120 Fbetween its 5 % and 95 % vo
14、l in accordance with Test Method D11601This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility ofSubcommittee D02.10.0A on Physical/Chemical Properties.Current edition approved April 1, 2015. Published May 20
15、15. Originallyapproved in 1984. Last previous edition approved in 2010 as D4419 90 (2010).DOI: 10.1520/D4419-90R15.2For 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 t
16、he standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1boiling points (converted to 760 torr). The DSC
17、method cannot differen-tiate between solid-liquid and solid-solid transitions. Such informationmust 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 hy
18、drocarbons withdifferent molecular weights, 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
19、 the highest tem-perature transition of each wax is the major first-ordertransition, its relative width should correlate with the relativewidth of the waxs molecular weight distribution.6. Interferences6.1 The test specimen must be homogeneous and represen-tative. The small sample size (10 mg) makes
20、 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.6.3 The heating rate must be the specified 10 C min 61 C min. Faster or slower rates will produce a differenttransition temperature and
21、transition peak width.7. Apparatus7.1 Differential Scanning Calorimeter, operating in eitherpower compensation or heat flux mode, capable of heating at10 C min 6 1 C min from 15 C to 150 C. Controlledcooling capability is preferred but not essential. The calorim-eter must be able to record automatic
22、ally the differential signal(WE or WT) versus temperature with a temperature repeatabil-ity of 60.5 C. If the differential record is versus time, thecalorimeter must have the capability to make a simultaneousrecord of temperature versus time.7.2 Sample Pans, of aluminum or other metal of highthermal
23、 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 cooling and free from interfering transi-tions. The specific heat capacity of the reference should be asclose as possible
24、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.9. Calibration9.1 Using the instrument manufacturers recommendedprocedure, calibrate the instruments temperature scal
25、e overthe temperature range of interest with appropriate standards.These include, but are not limited to:Melting PointStandard 99 % Purity Min. C KPhenoxybenzene (1)426.9 300.0p-Nitrotoluene (2) 51.5 324.8Naphthalene (3) 80.3 353.6Benzoic AcidA122.4 395.7Adipic Acid (4) 153.0 426.3Indium Metal (1) 1
26、56.6 429.9ASeeTest Method D3418. 99.98 % purity available from U.S. Bureau of Standardsas 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 entire
27、sample by heating it to 10 C 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 aluminumfoil to form a thin wax film. Separate the wax from the foil, andbreak it into pieces.11. Procedure11.1 Weigh 10 mg 6 1 mg
28、 of the wax pieces into a samplepan, and insert the pan in 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 ad
29、vantageousto 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 ) improves pan contact and establishes the samethermal history for every sample.11.2 Flush the sample compartment of the test
30、cell with inertgas throughout the test; a flow of 10 mL min to 50 mL min istypical.11.3 Perform a thermal precycle (Note 3). Heat the test cellat 10 C min 6 1 C min to 20 C 6 5 C beyond the end ofmelting, beyond the return to the base line (Note 4 and Note 5).Then cool the test cell to 15 C 6 5Cat10
31、Cmin61 C min. Hold the test cell at 15 C 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 % to95 % of full scale.NOTE 5The exposure of the sample to high temperatures should beminimized to prevent decom
32、position. 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 C min 6 1 C min to 20 C 6 5 C beyondthe end of melting (Note 6). Record the DSC curve using aheating rate of 10 C min 6 1 C min from 15
33、C to 20 C 65 C beyond the end of melting.NOTE 6A cooling (solidification) scan is also possible, but thetransition peak apex will be several degrees Celsius lower than thatobtained using a heating scan.4The boldface numbers in parentheses refer to the list of references at the end ofthis test method
34、.D4419 90 (2015)212. 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 intersection of the tangents to the peak slopes(Note 7 and Note 8).NOTE 7The extr
35、apolated onset (TO) and end (TE) temperatures arelocated by the intersection of the peak tangents with the base line (see Fig.1). 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 thetran
36、sition 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 indicatedby the temperature-scale calibration.13. Report13.1 Report the co
37、rrected apex and end temperatures foreach of the transition peaks to the nearest 0.5 C in order ofoccurrence. First thermal transition apex (T1A), first thermaltransition end temperature (T1E), second thermal transiton apextemperature (T2A), and second thermal transition end tempera-ture (T2E), tran
38、sition 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 difference between successivetest results, obtained by the same operator wit
39、h 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-Liquid Transition TemperaturesApex, T2AEnd, T2E0.81.0(1.4)(1.8)Solid-Solid
40、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 material, would, inthe long run, in the normal and correct operation of the tes
41、tmethod, 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 differentiate between solid-liquid and solid-solidtransitions; other techni
42、ques must be used for example, melting point inaccordance with Test Method D87.14.1.3 The first thermal transition temperature precisiondata are based on duplication determinations on five differentpetroleum waxes in an interlaboratory study among six labo-ratories. The second thermal transition tem
43、perature 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 transition temperatures can be definedonly in terms of a test method.15. Keyword
44、s15.1 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 Curve(Heating Cycle)D4419 90 (2015)3REFERENCES(1) Rossini, F. D., Pure Appl
45、ied Chemistry, Vol 22, 1970, p. 557.(2) Timmermans and Hennant-Roland, J. Chim. Physics, Vol 34, 1937, p.693.(3) API Project 44, Vol I, Tables 23-2-(33.5200)A and AE.(4) Morrison, J. D. and Robertson, J. M. J. Chem. Soc. London, 1949, p.987.(5) Mackenzie, R. C.,“Nomenclature in Thermal Analysis, Par
46、t IV,”Journal of Thermal Analysis, 13, 1978, p. 387.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 expressly advised that determination of the validity of any such patent rig
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