ASTM E1782-2014 Standard Test Method for Determining Vapor Pressure by Thermal Analysis《用热分析法测定蒸气压力的标准试验方法》.pdf
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1、Designation: E1782 14Standard Test Method forDetermining Vapor Pressure by Thermal Analysis1This standard is issued under the fixed designation E1782; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num
2、ber 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 describes a procedure for the determi-nation of the vapor pressure of pure liquids or melts fromboiling point measurement
3、s made using differential thermalanalysis (DTA) or differential scanning calorimetry (DSC)instrumentation operated at different applied pressures.1.2 This test method may be used for the temperature range273 to 773 K (0 to 500C) and for pressures between 0.2 kPato 2 MPa. These ranges may differ depe
4、nding upon theinstrumentation used and the thermal stability of materialstested. Because a range of applied pressures is required by thistest method, the analyst is best served by use of instrumenta-tion referred to as high pressure differential thermal instrumen-tation (HPDSC or HPDTA).1.3 The valu
5、es stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard. (See also IEEE/ASTM SI 10.)1.4 There is no ISO standard equivalent to this test method.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its
6、 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. Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias inASTM Test Method
7、sE473 Terminology 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-lyzersE1142 Terminology Relatin
8、g to Thermophysical PropertiesE2071 Practice for Calculating Heat of Vaporization orSublimation from Vapor Pressure DataIEEE/ASTM SI 10 Standard for Use of the InternationalSystem of Units (SI) The Modern Metric System3. Terminology3.1 Definitions:3.1.1 The following terms are applicable to this tes
9、t methodand can be found in either Terminology E473 or TerminologyE1142: boiling pressure, boiling temperature, differential scan-ning calorimetry (DSC), differential thermal analysis (DTA),vapor pressure, vaporization point, vaporization temperature.3.2 Symbols:3.2.1 A, B, CAntoine vapor pressure e
10、quation (1)3con-stants (log10, kPa, K):Antoinevaporpressureequation:Log10P 5 A 2 B/T1C!where:P = vapor pressure, kPa, andT = temperature, K.4. Summary of Test Method4.1 A specimen in an appropriate container is heated at aconstant rate within a DTA or DSC instrument operated underan applied constant
11、 vacuum/pressure between 0.2 kPa and 2MPa until a boiling endotherm is recorded. Boiling is observedat the temperature where the specimen partial pressure equalsthe pressure applied to the test chamber. The pressure isrecorded during observation of the boiling endotherm and theboiling temperature is
12、 recorded as the extrapolated onsettemperature. This measurement is repeated using new speci-mens for each of five or more different pressures covering thepressure range of interest. The pressure-temperature data arefitted as Log10P and 1/T (K1) to the Antoine vapor pressureequation (see Fig. 1). Va
13、por pressure values required forspecific reports are then computed from the derived equation.1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on Calo-rimetry and Mass Loss.Current edition approved March 15
14、, 2014. Published April 2014. Originallyapproved in 1996. Last previous edition approved in 2008 as E1782 08. DOI:10.1520/E1782-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informa
15、tion, refer to the standards Document Summary page onthe ASTM website.3The boldface numbers in parentheses refer to a list of references at the end ofthis standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 The capability of
16、the assembled system after calibrationshould be periodically checked by using this method on purewater as a reference substance and comparing the derivedvapor pressure data with the NBS/NRC steam tables attachedas Appendix X1. For pressures below 5 kPa, operation of theassembled system may be checke
17、d using 1-octanol (2).5. Significance and Use5.1 Vapor pressure is a fundamental thermophysical prop-erty of a liquid. Vapor pressure data are useful in processdesign and control, in establishing environmental regulationsfor safe handling and transport, for estimation of volatileorganic content (VOC
18、), and in deriving hazard assessments.Vapor pressure and boiling temperature data are required forMaterial Safety Data Sheets (MSDS). The enthalpy of vapor-ization may also be estimated from the slope of the vaporpressure curve (see Practice E2071).6. Interferences6.1 This test method is limited to
19、materials that exhibit asingle sharp boiling endotherm under the conditions outlined inthis test method.6.2 Oxidation, pyrolysis, or polymerization of condensedorganic materials retained at temperatures above their ambientboiling point may be encountered at the elevated pressures ofthis method. This
20、 will be observed as an exotherm or asignificantly broadened endotherm, or both, and shall not beconsidered a valid pressure-temperature datum point. Use of aninert gas for elevated pressures or for back-filling after evacu-ation of the sample chamber is recommended to minimize therisk of oxidation.
21、6.3 Partial blockage of the pinhole in the DSC containerscould occasionally be encountered. This may be observed asnoise spikes on the boiling endotherm and shall not beconsidered a valid pressure-temperature datum point7. Apparatus7.1 The essential equipment required to provide the mini-mum instrum
22、ent capability of this test method includes (seeFig. 2):7.1.1 Differential Scanning Calorimeter (DSC) or Differen-tial Thermal Analyzer (DTA), consisting of:7.1.1.1 DSC/DTA Test Chamber, composed of a furnace(s)to provide uniform controlled heating of a specimen andreference at a constant rate withi
23、n the 273 to 773 K temperaturerange of this test method; a temperature sensor to provide anindication of the specimen/furnace temperature to 61K;adifferential sensor to detect a difference (temperature or heatflow) between the specimen and reference equivalent to 5 mW;and a means of sustaining an in
24、ert gas or vacuum test chamberenvironment at pressures above and below ambient.FIG. 1 Vapor Pressure Curve with Experimental Data and An-toine Equation FitNOTE 1“A”, DSC/DTA instrument; “B,” pressure transducer; “C,”pressure/vacuum source; “D,” pressure stabilizer; “E,” pressure regula-tor; and “F,”
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