ASTM D1696-95(2000)
(Test Method)Standard Test Method for Solubility of Cellulose in Sodium Hydroxide
Standard Test Method for Solubility of Cellulose in Sodium Hydroxide
SCOPE
1.1 This test method is intended for application to dissolving-type cellulose pulps prepared from cotton or wood. The procedure is not directly applicable to unrefined pulps for use in chemical conversion processes because solubility equilibrium may not be attained within the specified extraction time.
1.2 This standard may involve hazardous materials, operations, and equipment. 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 consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D1696–95 (Reapproved 2000)
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope result. Sodium hydroxide concentrations of 10, 18, and 21.5%
2 are most frequently used. Data are reported as percent of dry
1.1 This test method is intended for application to
sample weight.
dissolving-type cellulose pulps prepared from cotton or wood.
3.2 Theextractionprocedureavoidsdilutionsequences,and
The procedure is not directly applicable to unrefined pulps for
therefore,theresultsarenotcomparabletodataobtainedbythe
use in chemical conversion processes because solubility equi-
alpha, beta, gamma methods of pulp fractionation (see TAPPI
librium may not be attained within the specified extraction
Method T429). The terms “alpha-,” “beta-,” or“gamma-”
time.
cellulosemustnotbeappliedtoanytestvaluesobtainedbythis
1.2 TThis standard does not purport to address all of the
procedure since they are defined only by the method of their
safety concerns, if any, associated with its use. It is the
determination.
responsibility of the user of this standard to consult and
3.3 Theessentialfeatureofthemethodistopreparesodium
establish appropriate safety and health practices and deter-
hydroxide extracts and oxidize the soluble material with
mine the applicability of regulatory limitations prior to use.
dichromate as described. Alternative methods of estimating
2. Referenced Documents dichromate by titration with ferrous ammonium sulfate and
sodium thiosulfate are described.
2.1 ASTM Standards:
D1193 Specification for Reagent Water
4. Significance and Use
D1347 Test Methods for Methylcellulose
4.1 The measurement of soluble oxidizable components of
D1348 Test Methods for Moisture in Cellulose
cellulose in sodium hydroxide is indicative of the purity of the
2.2 TAPPI Standard:
cellulose sample, since pure cellulose is insoluble in sodium
T 429 Method for Alpha-Cellulose in Paper
hydroxide. The extracted components are typically hemicellu-
3. Summary of Test Method loses, which are naturally present in the wood. Differences in
pulp purity can have a dramatic impact on the processing and
3.1 Pulp is steeped in a sodium hydroxide solution of a
properties of the cellulose derivatives produced from the pulp.
specified concentration for1hat 20°C. The soluble fraction is
estimated by dichromate oxidation of the filtered steeping
5. Apparatus
alkali.Theconcentrationofsodiumhydroxideusedinthepulp
5.1 Constant-Temperature Bath—A water bath maintained
extraction process must be reported as part of the analytical
at 20 6 0.2°C.
5.2 Stirrer—Mechanical stirrer as shown in Fig. 1.All parts
This test method is under the jurisdiction of ASTM Committee D-1 on Paint
in contact with solutions must be of stainless steel. The stirrer
and Related Coatings, Materials, andApplications and is the direct responsibility of
motor shall be a variable speed laboratory motor with 1500
Subcommittee D01.36 on Cellulose and Cellulose Derivatives.
rpm max speed.
Current edition approved Sept. 15, 1995. Published November 1995. Originally
5.3 Fritted-Glass Filter Crucible— A fritted-glass filter
published as D1696–59. Last previous edition D1696–90.
This test method is an adaptation of the method designated CCA 8:55 by the
crucible, coarse porosity (pore size 40 to 60 µm), of 30-mL
Analysis Committee of the Central Committee of the Cellulose Industry of the
capacity.
Swedish Association of Pulp and Paper Engineers. This test method is also
5.4 Electrometric Titration Apparatus— For estimation of
comparable with the TAPPI Tentative Standard T235 m-58, Solubility of Pulp in
Cold Sodium Hydroxide. dichromate by titration with ferrous ammonium sulfate. An
Annual Book of ASTM Standards, Vol 11.01.
indicator may be used as described in 8.6, but for rapid,
Annual Book of ASTM Standards, Vol 06.03.
accurate analysis an electrometric apparatus is recommended.
Available from TAPPI P. O. Box 105113, Atlanta, GA 30348.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D1696
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
6. Purity of Reagents 7. Reagents
7.1 Ferroin (0.025 M)—Dissolve 1.48 g of orthophenan-
6.1 Reagent grade chemicals shall be used in all tests.
throline monohydrate (or 1.624 g of the hydrochloride) with
Unlessotherwiseindicated,itisintendedthatallreagentsshall
0.695 g of ferrous sulfate (FeSO ) in water and dilute to 100
conform to the specifications of the Committee on Analytical 4
mL.
Reagents of the American Chemical Society, where such
7.2 Ferrous Ammonium Sulfate Solution (0.1 N)—Dissolve
specifications are available. Other grades may be used, pro-
40 to 41 g of ferrous ammonium sulfate (FeSO (NH ) -SO
4 4 2
vided it is first ascertained that the reagent is of sufficiently
4·6H O) in water containing 10 mL of H SO and dilute to 1
2 2 4
high purity to permit its use without lessening the accuracy of
litre in a volumetric flask. Standardize the solution daily
the determination.
against potassium permanganate (KMnO ).
6.2 Unless otherwise indicated, references to water shall be
7.3 Potassium Dichromate Solution(20g/L)—Weigh20.0g
understood to mean reagent water conforming to Specification
of potassium dichromate (K Cr O ), transfer to a 2-L beaker,
2 2 7
D1193.
and dissolve in approximately 700 mL of water. Add, with
constant stirring, 150 mL of H SO . Allow to cool to room
2 4
temperature. Dilute to 1 L with water.
7.4 Potassium Iodide (KI).
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia This reagent is required only for the iodometric method for measuring
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, dichromate (see section 9.7). Thyodene, supplied by Fisher Scientific Co., Pitts-
MD. burgh, PA is an acceptable substitute.
D1696
7.5 Sodium Hydroxide Solution—Dissolve solid sodium in the alkali. Cover the beaker with a watch glass and leave in
hydroxide (NaOH) in an equal weight of water. Cover and the20°Cbathuntilatotalof60minhaveelapsedfromthetime
allow to stand about one week to permit settling of sodium of addition of NaOH to the sample. For solubility determina-
carbonate (Na CO ). Prepare the dilute NaOH solutions listed tionsin10%NaOHsolution,allextractionoperationsmustbe
2 3
below by approximate addition of freshly boiled water to performed with the sample container in the constant-
portions of the concentrated stock solution. Use a siphon to temperature water bath. In work with 18 or 21.5% NaOH, the
withdraw the required volume of 50% NaOH solution from sample container may be removed from the bath for the
the stock bottle; do not disturb the Na CO precipitate. The disintegration process.
2 3
Na CO content of the dilute solutions should not exceed 1
2 3
NOTE 1—Most pulps are completely disintegrated after 3 min. A
g/L. Standardize the final dilute solutions by titration with
reasonable increase in the time of disintegration does not sensibly affect
standard acid.
the solubility. On the other hand, low values are obtained if the
7.5.1 Sodium Hydroxide Solution (10%)—Prepare a solu- disintegration is not complete. The stirrer should, therefore, be run until
complete disintegration is obtained, even if the time required exceeds 3
tion containing 10.0 6 0.1 g NaOH per 100 g of solution.
min.
Specific gravity at 20/4°C is 1.1089. This solution is 2.77 N.
7.5.2 Sodium Hydr
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.