ASTM D6942-03(2008)
(Test Method)Standard Test Method for Stability of Cellulose Fibers in Alkaline Environments
Standard Test Method for Stability of Cellulose Fibers in Alkaline Environments
SIGNIFICANCE AND USE
This method is intended to provide a generalized procedure for determining the stability of cellulosic pulp fibers exposed to alkaline environments. Specifically, this method allows various pulp types to be compared with respect to the effect of exposure to alkaline conditions on the strength of individual cellulosic fibers based on a zero-span tensile test. The time intervals listed in the procedure are not critical, and more intervals of shorter or longer duration may be added. In addition, the procedure may be simplified by removing some of the intermediate intervals so long as a range of intervals is determined. An example of a simplified procedure would be to determine 4 intervals (for example, 1 day, 1 week, 2 weeks, 4 weeks; or 1 day, 3 day, 7 day, 14 day).
The specified solution (1N NaOH) is strongly alkaline. Although this alkali concentration is higher than some environments that would be simulated by this test, the stronger pH provides better differentiation between different cellulose fiber types. Although alkaline stability based on other alkalis (for example, KOH, Ca(OH)2, etc.) at a different concentration could be determined by this method, 1N NaOH is to be considered the standard solution. Alkaline stability results from other treatments may be reported in addition to the standard solution if the additional solution(s) provide useful information.
SCOPE
1.1 This test method describes a procedure for determining the effect of exposure to alkaline environments on the strength of cellulose fibers. An alkaline environment is defined to be any matrix in which the pH is greater than 8 for a period of 2 or more hours.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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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Designation: D6942 − 03 (Reapproved 2008)
StandardTest Method for
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Stability of Cellulose Fibers in Alkaline Environments
This standard is issued under the fixed designation D6942; 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 alkaline solution. The stability factor defined below can be
usedtomeasuretheeffectofexposuretoalkalineconditionson
1.1 This test method describes a procedure for determining
fiber strength.
the effect of exposure to alkaline environments on the strength
of cellulose fibers. An alkaline environment is defined to be
4.2 Cellulose fibers are treated with a standard alkaline
any matrix in which the pH is greater than 8 for a period of 2
solution for a specified interval, washed free of alkali, and then
or more hours.
formed into standard handsheets (see TAPPI T 205) for
1.2 The values stated in SI units are to be regarded as
strength testing. Zero-span tensile testing (see TAPPI T 231) is
standard. No other units of measurement are included in this
used to determine the effect on fiber strength.
standard.
4.3 A stability ratio is defined based on the ratio of the
1.3 This standard does not purport to address all of the
zero-span tensile of alkali treated fibers divided by the zero-
safety concerns, if any, associated with its use. It is the
span tensile of untreated (control) fibers.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5. Significance and Use
bility of regulatory limitations prior to use.
5.1 This method is intended to provide a generalized pro-
2. Referenced Documents
cedure for determining the stability of cellulosic pulp fibers
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2.1 ASTM Standards:
exposed to alkaline environments. Specifically, this method
D1348 Test Methods for Moisture in Cellulose
allows various pulp types to be compared with respect to the
D1695 Terminology of Cellulose and Cellulose Derivatives
effect of exposure to alkaline conditions on the strength of
2.2 TAPPI (Technical Association of the Pulp & Paper
individual cellulosic fibers based on a zero-span tensile test.
Industry) Standards:
The time intervals listed in the procedure are not critical, and
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T 205 Forming Handsheets for Physical Tests of Pulp
more intervals of shorter or longer duration may be added. In
T 231 Zero-span Breaking Strength of Pulp (Dry Zero-span
addition,theproceduremaybesimplifiedbyremovingsomeof
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Tensile)
the intermediate intervals so long as a range of intervals is
determined.An example of a simplified procedure would be to
3. Terminology
determine 4 intervals (for example, 1 day, 1 week, 2 weeks, 4
3.1 Definitions—For standard terminology of cellulose and
weeks; or 1 day, 3 day, 7 day, 14 day).
cellulose derivatives, see Terminology D1695.
5.2 The specified solution (1N NaOH) is strongly alkaline.
4. Summary of Test Method
Although this alkali concentration is higher than some envi-
4.1 This test method can be used to compare different
ronments that would be simulated by this test, the stronger pH
cellulose pulp fiber types based on their response to a standard
provides better differentiation between different cellulose fiber
types. Although alkaline stability based on other alkalis (for
example, KOH, Ca(OH) , etc.) at a different concentration
1
This test method is under the jurisdiction of ASTM Committee D01 on Paint 2
and Related Coatings, Materials, andApplications and is the direct responsibility of could be determined by this method, 1N NaOH is to be
Subcommittee D01.36 on Cellulose and Cellulose Derivatives.
consideredthestandardsolution.Alkalinestabilityresultsfrom
Current edition approved June 1, 2008. Published June 2008. Originally
other treatments may be reported in addition to the standard
approved in 2003. Last previous edition approved in 2003 as D6942 – 03. DOI:
10.1520/D6942-03R08. solution if the additional solution(s) provide useful informa-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
tion.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 6. Interferences
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Available from TechnicalAssociation of the Pulp and Paper Industry (TAPPI),
15 Technology Parkway South, Norcross, GA 30092, http://www.tappi.org. 6.1 There are no known interferences for this method.
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D6942 − 03 (Reapproved 2008)
7. Apparatus re
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