ASTM D7129-05

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An American National Standard
Designation:D7129–05
Standard Test Method for
Determination of Ammonia Trapping in a Grafted Battery
Separator
This standard is issued under the fixed designation D7129; 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 4.2 Results are calculated as mol/g using the appropriate
equations.
1.1 This test method covers the measurement of the ability
of a material to capture ammonia.
5. Significance and Use
1.2 Thistestmethodisintendedprimarilyfortestinggrafted
5.1 Nickel metal hydride (Ni-MH) cells can exhibit high
polyolefin materials used as a battery separator, although other
self-discharge rates. Nitrate impurities in the positive electrode
materials could be tested.
can be reduced to ammonia on the negative electrode. This
1.3 The values stated in SI units are to be regarded as the
causes rapid self-discharge. Technical publications have re-
standard.
ported a link between the separator ammonia trapping capa-
1.4 This standard does not purport to address all of the
bilities and the cells charge retention. Grafted polyolefin
safety concerns, if any, associated with its use. It is the
separators can absorb or trap these impurities—hence, reduc-
responsibility of the user of this standard to establish appro-
ing self-discharge rates. The level of ammonia trapping from
priate safety and health practices and determine the applica-
this method gives an indication of the efficiency of a separator
bility of regulatory limitations prior to use.
to trap these contaminates, thus helping a battery self discharge
2. Referenced Documents ( charge retention). A higher value should provide a cell with
greater charge retention.
2.1 ASTM Standards:
D123 Terminology Relating to Textiles
6. Apparatus
E438 Specification for Glasses in Laboratory Apparatus
6.1 Flask, Erlenmeyer, wide mouth, 250 mLcapacity with a
E1272 Specification for Laboratory Glass Graduated Cylin-
screw cap.
ders
6.2 Flask, Erlenmeyer, wide mouth, 500 mL capacity.
3. Terminology 6.3 Cylinder, Graduated, Class A, 250 mL capacity.
3.1 Definitions:
NOTE 1—The tolerance on the accuracy of the graduations in Specifi-
3.1.1 For definitions on other textile terms in this test cationE1272forthisapparatusis 61.4mL.Ifgreateraccuracyisrequired
for a test result, the graduated trap(s) should be calibrated.
method, refer to Terminology D123
6.4 Pipette, Volumetric, Class A, 10 mL capacity.
4. Summary of Test Method
NOTE 2—The tolerance on the accuracy of the graduations in Specifi-
4.1 A predetermined amount of separator and ammonium
cation E438 for this apparatus is 60.02 mL . If greater accuracy is
hydroxide is added together in a KOH solution.The specimens
required for a test result, the graduated trap(s) should be calibrated
are conditioned under a controlled temperature for 24 h. After
6.5 Pipette, Volumetric, Class A, 3- mL capacity.
the solution is cooled, the solutions are distilled to determine
the amount of ammonia the separator retained.
NOTE 3—The tolerance on the accuracy of the graduations in Specifi-
cationE438forthisapparatusis 60.01mL.Ifgreateraccuracyisrequired
for a test result, the graduated trap(s) should be calibrated.
This test method is under the jurisdiction of ASTM Committee D09 on
6.6 Distillation Unit, Micro or macro Kjeldhal apparatus.
Electrical and Electronic Insulating Materials and is the direct responsibility of
6.7 Oven.
Subcommittee D09.19 on Dielectric Sheet and Roll Products.
Current edition approved March 1, 2005. Published March 2005. DOI: 10.1520/
7. Reagents
D7129-05.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
7.1 Ammonium Hydroxide, 0.3M(NH OH), ACS grade.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
7.2 Hydrochloric Acid, 0.1M (HCL), ACS grade.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 7.3 Methyl Red, ACS grade.
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D7129–05
7.4 Potassium Hydroxide Solution, 8M—Prepare a suffi- 9.4 Measure out 1
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