ASTM D6942-03(2019)
(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
5.1 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).
5.2 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6942 − 03 (Reapproved 2019)
Standard Test Method for
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 3. Terminology
1.1 This test method describes a procedure for determining
3.1 Definitions—For standard terminology of cellulose and
the effect of exposure to alkaline environments on the strength
cellulose derivatives, see Terminology D1695.
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
4. Summary of Test Method
or more hours.
4.1 This test method can be used to compare different
1.2 The values stated in SI units are to be regarded as
cellulose pulp fiber types based on their response to a standard
standard. No other units of measurement are included in this
alkaline solution. The stability factor defined below can be
standard.
usedtomeasuretheeffectofexposuretoalkalineconditionson
1.3 This standard does not purport to address all of the
fiber strength.
safety concerns, if any, associated with its use. It is the
4.2 Cellulose fibers are treated with a standard alkaline
responsibility of the user of this standard to establish appro-
solution for a specified interval, washed free of alkali, and then
priate safety, health, and environmental practices and deter-
formed into standard handsheets (see TAPPI T 205) for
mine the applicability of regulatory limitations prior to use.
strength testing. Zero-span tensile testing (see TAPPI T 231) is
1.4 This international standard was developed in accor-
used to determine the effect on fiber strength.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4.3 A stability ratio is defined based on the ratio of the
Development of International Standards, Guides and Recom-
zero-span tensile of alkali treated fibers divided by the zero-
mendations issued by the World Trade Organization Technical
span tensile of untreated (control) fibers.
Barriers to Trade (TBT) Committee.
5. Significance and Use
2. Referenced Documents
5.1 This method is intended to provide a generalized pro-
2.1 ASTM Standards:
cedure for determining the stability of cellulosic pulp fibers
D1348 Test Methods for Moisture in Cellulose (Withdrawn
exposed to alkaline environments. Specifically, this method
2017)
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
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
Tensile)
the intermediate intervals so long as a range of intervals is
determined.An example of a simplified procedure would be to
This test method is under the jurisdiction of ASTM Committee D01 on Paint
determine 4 intervals (for example, 1 day, 1 week, 2 weeks, 4
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.36 on Cellulose and Cellulose Derivatives.
weeks; or 1 day, 3 day, 7 day, 14 day).
Current edition approved Dec. 1, 2019. Published December 2019. Originally
approved in 2003. Last previous edition approved in 2012 as D6942 – 03 (2012).
5.2 The specified solution (1N NaOH) is strongly alkaline.
DOI: 10.1520/D6942-03R19.
Although this alkali concentration is higher than some envi-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ronments that would be simulated by this test, the stronger pH
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
provides better differentiation between different cellulose fiber
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
types. Although alkaline stability based on other alkalis (for
The last approved version of this historical standard is referenced on
example, KOH, Ca(OH) , etc.) at a different concentration
www.astm.org.
4 could be determined by this method, 1N NaOH is to be
Available from TechnicalAssociation of the Pulp and Paper Industry (TAPPI),
15 Technology Parkway South, Norcross, GA 30092, http://www.tappi.org. consideredthestandardsolution.Alkalinestabilityresultsfrom
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6942 − 03 (2019)
other treatments may be reported in addition to the standard but the starting consistency must still be 30 %.) The sample
solution if the additional solution(s) provide useful informa- may be placed in an uncovered beaker to simulate an environ-
tion. ment that is open to the atmosphere, or placed in a sealed bag
to simulate an environment in which the consistency would
6. Interferences
remain constant.
6.1 There are no known interferences for this method.
13.3 Repeat step 13.2 to prepare five more samples that will
be left to age for time intervals of 3, 7, 14, 21, and 28 days,
7. Apparatus
respectively. Once the time interval has been met, work-up of
7.1 Handsheeting Apparatus, as defined in TAPPI T 205.
the samples is accomplished by collecting fibers on a wire
screen (100 mesh), washing with tap water until washings are
7.2
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