ASTM D4419-90(1995)e1
(Test Method)Standard Test Method for Measurement of Transition Temperatures of Petroleum Waxes by Differential Scanning Calorimetry (DSC)
Standard Test Method for Measurement of Transition Temperatures of Petroleum Waxes by Differential Scanning Calorimetry (DSC)
SCOPE
1.1 This test method measures the transition temperatures of petroleum waxes, including microcrystalline waxes, by differential scanning calorimetry (DSC). These transitions may occur as a solid-solid transition or as a solid-liquid transition.
1.2 The normal operating temperature range extends from 15oC to 150oC (Note 1).
1.3 The values stated in SI units are to be regarded as the standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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e1
Designation: D 4419 – 90 (Reapproved 1995) An American National Standard
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Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Measurement of Transition Temperatures of Petroleum
Waxes by Differential Scanning Calorimetry (DSC)
This standard is issued under the fixed designation D 4419; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Section 15 was added editorially in June 1995.
1. Scope ture, while the substance and a reference material are subjected
to a controlled temperature program. The record is the DSC
1.1 This test method measures the transition temperatures of
curve. Two modes, power-compensation DSC and heat-flux
petroleum waxes, including microcrystalline waxes, by differ-
DSC, can be distinguished depending on the method of
ential scanning calorimetry (DSC). These transitions may
measurement used. For additional background information
occur as a solid-solid transition or as a solid-liquid transition.
refer to Practice E 472, Terminology E 473, and Test Method
1.2 The normal operating temperature range extends from
E 474.
15°C to 150°C (Note 1).
1.3 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
4.1 Separate samples of petroleum wax and a reference
responsibility of the user of this standard to establish appro-
material or blank (empty sample container) are heated at a
priate safety and health practices and determine the applica-
controlled rate in an inert atmosphere. A sensor continuously
bility of regulatory limitations prior to use.
monitors the difference in heat flow to the two samples. The
1.4 The values stated in SI units are to be regarded as the
DSC curve is a record of this difference versus temperature. A
standard.
transition in the wax involves the absorption of energy relative
2. Referenced Documents to the reference, resulting in an endothermic peak in the DSC
curve. While the transition occurs over the temperature range
2.1 ASTM Standards:
spanned by the base of the peak, the temperature associated
D 87 Test Method for Melting Point of Petroleum Wax
with the peak apex is designated the nominal transition
(Cooling Curve)
temperature (Note 1).
D 1160 Test Method for Distillation of Petroleum Products
at Reduced Pressures
NOTE 1—Test Method D 87 also monitors energy transfer between wax
D 3418 Test Method for Transition Temperatures of Poly-
and a standard environment. The highest temperature DSC transition may
mers by Thermal Analysis differ from the melting point because the two methods approach the
solid/liquid phase transition from different directions.
E 472 Practice for Reporting Thermoanalytical Data
E 473 Terminology Relating to Thermal Analysis
5. Significance and Use
E 474 Test Method for Evaluation of Temperature Scale for
5 5.1 DSC in a convenient and rapid method for determining
Differential Thermal Analysis
the temperature limits within which a wax undergoes during
transitions. The highest temperature transition is a solid-liquid
3. Terminology
transition associated with complete melting; it can guide the
3.1 Definitions of Terms Specific to This Standard:
choice of wax storage and application temperatures. The
3.1.1 Differential Scanning Calorimetry (DSC)—A tech-
solid-solid temperature transition is related to the properties of
nique in which the difference in energy inputs into a substance
the solid, that is, hardness and blocking temperature.
and a reference material is measured as a function of tempera-
NOTE 2—For a relatively narrow cut petroleum wax, the lowest
transition will be a solid-solid transition. A narrow cut wax is one obtained
1 by deoiling a single petroleum distillate with a maximum range of 120°F
This test method is under the jurisdiction of ASTM Committee D-2 on
between its 5 % and 95 % vol in accordance with Test Method D 1160
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
boiling points (converted to 760 torr). The DSC method cannot differen-
D02.10.0A on Physical and Chemical Properties.
Current edition approved May 25, 1990. Published July 1990. Originally tiate between solid-liquid and solid-solid transitions. Such information
published as D 4419 – 84. Last previous edition D 4419 – 84.
must be predetermined by other techniques. In the case of blends, the
Annual Book of ASTM Standards, Vol 05.01.
lower temperature transition may be envelopes of both solid-liquid and
Annual Book of ASTM Standards, Vol 08.02.
solid-solid transitions.
Annual Book of ASTM Standards, Vol 14.02.
Discontinued; see 1985 Annual Book of ASTM Standards, Vol 14.02. 5.2 Since petroleum wax is a mixture of hydrocarbons with
D 4419
A
See Test Method D 3418. 99.98 % purity available from U.S. Bureau of
different molecular weights, its transitions occur over a tem-
Standards as SRM 350.
perature range. This range is one factor that influences the
9.2 The specimen weight and test procedure should be those
width, expressed in° C, of the DSC peaks. The highest
specified in Section 10, except that the precycle (11.3) is
temperature transition is a first-order transition. If, for a series
omitted.
of waxes, there is supporting evidence that the highest tem-
perature transition of each wax is the major first-order transi- 10. Specimen Preparation
tion, its relative width should correlate with the relative width
10.1 To ensure homogeneity, completely melt the entire
of the wax’s molecular weight distribution.
sample by heating it to 10°C above the temperature at which
the wax is completely molten. Using a clean eyedropper,
6. Interferences
transfer a few drops to the surface of a clean sheet of aluminum
foil to form a thin wax film. Separate the wax from the foil, and
6.1 The test specimen must be homogeneous and represen-
break it into pieces.
tative. The small sample size (10 mg) makes these require-
ments particularly important.
11. Procedure
6.2 Intimate thermal contact, sample-to-pan and pan-to-
11.1 Weigh 10 6 1 mg of the wax pieces into a sample pan,
sensor, is essential to obtain accurate and reproducible results.
and insert the pan in the calorimeter sample compartment.
6.3 The heating rate must be the specified 10 6 1°C/min.
NOTE 3—Intimate thermal contact, sample-to-pan and pan-to-sensor, is
Faster or slower rates will produce a different transition
essential. Ensure that pan bottoms are flat and also that sensor surfaces
temperature and transition peak width.
where pans rest are clean. If the equipment is available, it is advantageous
to ensure maximum sample-to-pan thermal contact by crimping a metal
cover against the pan with the sample sandwiched in between. A thermal
7. Apparatus
precycle (see section 10.3) improves pan contact and establishes the same
7.1 Differential Scanning Calorimeter, operating in either
thermal history for every sample.
power compensation or heat flux mode, capable of heating at
11.2 Flush the sampl
...
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