ASTM D7389-07(2012)
(Test Method)Standard Test Method for Acid Number (Empirical) of Maleic Anhydride (MAH) Grafted Waxes
Standard Test Method for Acid Number (Empirical) of Maleic Anhydride (MAH) Grafted Waxes
SIGNIFICANCE AND USE
4.1 This test method is used to determine the free acid content of MAH-grafted waxes. The potential hydrolysis of the anhydride functionality of this wax in storage makes them unsuitable for determining free acid content by Test Method D1386. Free acid content is a significant quality control test, and is a determinant of the utility of the wax.
SCOPE
1.1 This test method covers the determination of the acid number of maleic anhydride (MAH) grafted waxes. The number is obtained by direct titration of the material and indicates the amount of free acid present.
1.2 This test method is applicable to MAH-grafted waxes because it uses a special sample preparation step (7.1) that is not required for other waxes. The special sample preparation reverses the hydrolysis of acid anhydride that can occur during storage of the wax.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D7389 − 07 (Reapproved 2012)
Standard Test Method for
Acid Number (Empirical) of Maleic Anhydride (MAH) Grafted
Waxes
This standard is issued under the fixed designation D7389; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Significance and Use
4.1 This test method is used to determine the free acid
1.1 This test method covers the determination of the acid
content of MAH-grafted waxes.The potential hydrolysis of the
number of maleic anhydride (MAH) grafted waxes. The
anhydride functionality of this wax in storage makes them
number is obtained by direct titration of the material and
unsuitable for determining free acid content by Test Method
indicates the amount of free acid present.
D1386. Free acid content is a significant quality control test,
1.2 This test method is applicable to MAH-grafted waxes
and is a determinant of the utility of the wax.
because it uses a special sample preparation step (7.1) that is
not required for other waxes. The special sample preparation
5. Apparatus
reverses the hydrolysis of acid anhydride that can occur during
5.1 Analytical Balance.
storage of the wax.
5.2 Buret, 50-mL, with 0.1-mL graduations.
1.3 The values stated in SI units are to be regarded as
5.3 Flasks, acid value, 250-mL.
standard. No other units of measurement are included in this
standard.
6. Reagents and Materials
1.4 This standard does not purport to address all of the
6.1 Purity of Reagents—Reagent-grade chemicals or
safety concerns, if any, associated with its use. It is the
equivalent, as specified in Practice E200, shall be used in all
responsibility of the user of this standard to establish appro-
tests.
priate safety and health practices and determine the applica-
6.2 Ethanolic Potassium Hydroxide, Standard Solution (0.1
bility of regulatory limitations prior to use.
N)—Dissolve 6.6 g of potassium hydroxide in 5.6 g of distilled
water. Dilute with USSD3Adenatured ethanol or 95 % ethanol
2. Referenced Documents
to 1000 mL. Standardize with 0.1 N hydrochloric acid.
2.1 ASTM Standards:
6.3 Phenolphthalein Indicator Solution (10 g/litre)—
D1386 Test Method for Acid Number (Empirical) of Syn-
Dissolve1gof phenolphthalein in 100 mL of USSD3A,
thetic and Natural Waxes
denatured ethanol or 95 % ethanol.
E200 Practice for Preparation, Standardization, and Storage
of Standard and Reagent Solutions for ChemicalAnalysis 6.4 Xylene.
7. Sample Preparation
3. Terminology
7.1 Melt20gofthesamplewaxina250-mLflaskorbeaker
3.1 Definitions:
and heat to 180–190°C. Apply a slight vacuum as the wax
3.1.1 acid number or acid value—the number of milligrams
melts and hold at temperature for 10 to 15 min, or as long as
of potassium hydroxide necessary to neutralize1gofthe
bubbles appear in the melt. If a vacuum is not available, hold
sample.
the sample at 180–190°C for 4 h. Determination of the acid
number is made immediately after dehydration. Over heating
or holding the sample for more than 4 h will cause excess
This test method is under the jurisdiction ofASTM Committee D21 on Polishes
darkening of the wax and making the end point difficult t
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