ASTM D1696-95(2019)e1

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.
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Designation: D1696 − 95 (Reapproved 2019)
Standard Test Method for
Solubility of Cellulose in Sodium Hydroxide
This standard is issued under the fixed designation D1696; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Section 2.1 was updated Editorially in December 2019.
1. Scope D1347 Test Methods for Methylcellulose (Withdrawn
2003)
1.1 This test method is intended for application to
D1348Test Methods for Moisture in Cellulose (Withdrawn
dissolving-type cellulose pulps prepared from cotton or wood. 4
2017)
The procedure is not directly applicable to unrefined pulps for
2.2 TAPPI Standard:
use in chemical conversion processes because solubility equi-
T429 Method for Alpha-Cellulose in Paper
librium may not be attained within the specified extraction
time.
3. Summary of Test Method
1.2 The values stated in SI units are to be regarded as
3.1 Pulp is steeped in a sodium hydroxide solution of a
standard. No other units of measurement are included in this
specified concentration for1hat 20°C. The soluble fraction is
standard. estimated by dichromate oxidation of the filtered steeping
alkali.Theconcentrationofsodiumhydroxideusedinthepulp
1.3 This standard does not purport to address all of the
extraction process must be reported as part of the analytical
safety concerns, if any, associated with its use. It is the
result. Sodium hydroxide concentrations of 10, 18, and 21.5%
responsibility of the user of this standard to establish appro-
are most frequently used. Data are reported as percent of dry
priate safety, health, and environmental practices and deter-
sample weight.
mine the applicability of regulatory limitations prior to use.
3.2 Theextractionprocedureavoidsdilutionsequences,and
1.4 This international standard was developed in accor-
therefore,theresultsarenotcomparabletodataobtainedbythe
dance with internationally recognized principles on standard-
alpha, beta, gamma methods of pulp fractionation (see TAPPI
ization established in the Decision on Principles for the
Method T429). The terms “alpha-,” “beta-,” or “gamma-”
Development of International Standards, Guides and Recom-
cellulosemustnotbeappliedtoanytestvaluesobtainedbythis
mendations issued by the World Trade Organization Technical
procedure since they are defined only by the method of their
Barriers to Trade (TBT) Committee.
determination.
3.3 Theessentialfeatureofthemethodistopreparesodium
2. Referenced Documents
hydroxide extracts and oxidize the soluble material with
dichromate as described. Alternative methods of estimating
2.1 ASTM Standards:
dichromate by titration with ferrous ammonium sulfate and
D1193Specification for Reagent Water
sodium thiosulfate are described.
4. Significance and Use
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
4.1 The measurement of soluble oxidizable components of
Subcommittee D01.36 on Cellulose and Cellulose Derivatives.
cellulose in sodium hydroxide is indicative of the purity of the
Current edition approved Dec. 1, 2019. Published December 2019. Originally
cellulose sample, since pure cellulose is insoluble in sodium
approved in 1959. Last previous edition approved in 2011 as D1696–95(2011).
hydroxide. The extracted components are typically
DOI: 10.1520/D1696-95R19E01.
This test method is an adaptation of the method designated CCA 8:55 by the
hemicelluloses, which are naturally present in the wood.
Analysis Committee of the Central Committee of the Cellulose Industry of the
Swedish Association of Pulp and Paper Engineers. This test method is also
comparable with the TAPPI Tentative Standard T235 m-58, Solubility of Pulp in
Cold Sodium Hydroxide. The last approved version of this historical standard is referenced on
For referenced ASTM standards, visit the ASTM website, www.astm.org, or www.astm.org.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Available from TechnicalAssociation of the Pulp and Paper Industry (TAPPI),
Standards volume information, refer to the standard’s Document Summary page on P.O.Box105113,Atlanta,GA30348;15TechnologyParkwaySouth,Norcross,GA
the ASTM website. 30092.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D1696 − 95 (2019)
Differences in pulp purity can have a dramatic impact on the 6. Purity of Reagents
processingandpropertiesofthecellulosederivativesproduced
6.1 Reagent grade chemicals shall be used in all tests.
from the pulp.
Unlessotherwiseindicated,itisintendedthatallreagentsshall
conform to the specifications of the Committee on Analytical
5. Apparatus
Reagents of the American Chemical Society, where such
5.1 Constant-Temperature Bath—A water bath maintained
specifications are available. Other grades may be used, pro-
at 20 6 0.2°C.
vided it is first ascertained that the reagent is of sufficiently
high purity to permit its use without lessening the accuracy of
5.2 Stirrer—Mechanical stirrer as shown in Fig. 1.All parts
the determination.
in contact with solutions must be of stainless steel. The stirrer
motor shall be a variable speed laboratory motor with 1500
6.2 Unless otherwise indicated, references to water shall be
rpm max speed.
understood to mean reagent water conforming to Specification
D1193.
5.3 Fritted-Glass Filter Crucible—A fritted-glass filter
crucible, coarse porosity (pore size 40 to 60 µm), of 30-mL
capacity.
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
Standard-Grade Reference Materials, American Chemical Society, Washington,
5.4 Electrometric Titration Apparatus—For estimation of
DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
dichromate by titration with ferrous ammonium sulfate. An
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
indicator may be used as described in 8.6, but for rapid,
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
accurate analysis an electrometric apparatus is recommended. copeial Convention, Inc. (USPC), Rockville, MD.
Metric Equivalents
1 1 1 3 1 1 5
in. ⁄8 ⁄4 ⁄2 ⁄4 1 3 ⁄4 6 ⁄2 8 ⁄8
mm 3.2 6.4 12.7 19.0 25.4 82.6 165.1 219.1
FIG. 1 Design Details of Mechanical Stirrer
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D1696 − 95 (2019)
7. Reagents 8.3 Determine the moisture content of the air-dry sample in
accordance with Test Methods D1348. Calculate the oven-dry
7.1 Ferroin (0.025 M)—Dissolve 1.48 g of orthophenan-
weight of the sample for the solubility determination.
throline monohydrate (or 1.624 g of the hydrochloride) with
0.695 g of ferrous sulfate (FeSO ) in water and dilute to 100
9. Procedure
mL.
9.1 Precool the NaOH solutions to 20°C. Pulp solubility in
7.2 Ferrous Ammonium Sulfate Solution (0.1 N)—Dissolve
18and21.5%NaOHsolutionsisnotaffectedbyafewdegrees
40 to 41 g of ferrous ammonium sulfate (FeSO (NH ) -
4 4 2
variation in temperature. Hence, temperatures of 20 6 2°C are
SO ·6H O) in water containing 10 mL of H SO and dilute to
4 2 2 4
satisfactory in this case. However, pulp solubility in 10%
1 litre in a volumetric flask. Standardize the solution daily
NaOH solution is very sensitive to temperature variation. The
against potassium permanganate (KMnO ).
operator must control temperature to 20 6 0.2°C in all phases
of pulp extraction with 10% NaOH solution.
7.3 Potassium Dichromate Solution (20 g/L)—Weigh20.0g
of potassium dichromate (K Cr O ), transfer to a 2-L beaker,
2 2 7
9.2 With a pipet or buret, transfer 100 mL of the NaOH
and dissolve in approximately 700 mL of water. Add, with
solution of the desired concentration (10, 18, or 21.5%) into a
constant stirring, 150 mL of H SO . Allow to cool to room
2 4
250-mL beaker. Add the 1.6 g air-dry pulp sample to the
temperature. Dilute to 1 L with water.
solution.Allow the pulp to swell for 2 min; then introduce the
7.4 Potassium Iodide (KI). stirring apparatus into the beaker so that the surface of the
liquid coincides with the draft tube top. Disintegrate the pulp
7.5 Sodium Hydroxide Solution—Dissolve solid sodium hy-
by stirring for 3 min (Note 1). Adjust the stirring speed to
droxide (NaOH) in an equal weight of water. Cover and allow
prevent addition of air to the slurry (about 1500 rpm). Remove
tostandaboutoneweektopermitsettlingofsodiumcarbonate
the stirrer. Carefully clean the stirring apparatus a
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