Standard Test Method for Acid Number (Empirical) of Maleic Anhydride (MAH) Grafted Waxes

SIGNIFICANCE AND USE
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 D 1386. 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.
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

Status
Historical
Publication Date
30-Sep-2007
Technical Committee
Drafting Committee
Current Stage
Ref Project

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ASTM D7389-07 - Standard Test Method for Acid Number (Empirical) of Maleic Anhydride (MAH) Grafted Waxes
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D7389 − 07
StandardTest 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 D1386. Free acid content is a significant quality control test,
and is a determinant of the utility of the wax.
1.1 This test method covers the determination of the acid
number of maleic anhydride (MAH) grafted waxes. The
5. Apparatus
number is obtained by direct titration of the material and
5.1 Analytical Balance.
indicates the amount of free acid present.
5.2 Buret, 50-mL, with 0.1-mL graduations.
1.2 This test method is applicable to MAH-grafted waxes
because it uses a special sample preparation step (7.1) that is
5.3 Flasks, acid value, 250-mL.
not required for other waxes. The special sample preparation
reverses the hydrolysis of acid anhydride that can occur during
6. Reagents and Materials
storage of the wax.
6.1 Purity of Reagents—Reagent-grade chemicals or
1.3 This standard does not purport to address all of the
equivalent, as specified in Practice E200, shall be used in all
safety concerns, if any, associated with its use. It is the
tests.
responsibility of the user of this standard to establish appro-
6.2 Ethanolic Potassium Hydroxide, Standard Solution (0.1
priate safety and health practices and determine the applica-
N)—Dissolve 6.6 g of potassium hydroxide in 5.6 g of distilled
bility of regulatory limitations prior to use.
water. Dilute with USSD3Adenatured ethanol or 95 % ethanol
to 1000 mL. Standardize with 0.1 N hydrochloric acid.
2. Referenced Documents
6.3 Phenolphthalein Indicator Solution (10 g/litre)—
2.1 ASTM Standards:
Dissolve1gof phenolphthalein in 100 mL of USSD3A,
D1386 Test Method for Acid Number (Empirical) of Syn-
denatured ethanol or 95 % ethanol.
thetic and Natural Waxes
E200 Practice for Preparation, Standardization, and Storage
6.4 Xylene.
of Standard and Reagent Solutions for ChemicalAnalysis
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
4. Significance and Use
or holding the sample for more than 4 h will cause excess
4.1 This test method is used to determine the free acid
darkening of the wax and making the end point difficult to see
content of MAH-grafted waxes.The potential hydrolysis of the
(8.2).
anhydride functionality of this wax in storage makes them
unsuitable for determining free acid content by Test Method
8. Procedure
8.1 Transfer 1 to2gofthe sample, weighed to the nearest
This test method is under the jurisdiction
...

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