ASTM D5897-96(2007)
(Test Method)Standard Test Method for Determination of Percent Hydroxyl on Cellulose Esters by Potentiometric Titration-Alternative Method
Standard Test Method for Determination of Percent Hydroxyl on Cellulose Esters by Potentiometric Titration-Alternative Method
SIGNIFICANCE AND USE
This test method provides a simpler means for the determination of the hydroxyl content of cellulose esters than the preparation and measurement of the carbanilate derivative described in Test Methods D 817 and D 871.
The hydroxyl content is an important indicator of solubility and reactivity.
SCOPE
1.1 This test method covers a procedure for determining the percent hydroxyl on cellulose esters by potentiometric titration. The typical range of percent hydroxyl measured is 0.7 to 10.0 %.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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.
General Information
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D5897 − 96 (Reapproved2007)
Standard Test Method for
Determination of Percent Hydroxyl on Cellulose Esters by
Potentiometric Titration—Alternative Method
This standard is issued under the fixed designation D5897; 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 the preparation and measurement of the carbanilate derivative
described in Test Methods D817 and D871.
1.1 This test method covers a procedure for determining the
percenthydroxyloncelluloseestersbypotentiometrictitration.
4.2 The hydroxyl content is an important indicator of
The typical range of percent hydroxyl measured is 0.7 to
solubility and reactivity.
10.0 %.
5. Interferences
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
5.1 Undissolved ester may accumulate on the sides of the
standard.
flask and on top of the stirring-star during dissolution, leading
1.3 This standard does not purport to address all of the to low results. Gently swirling the solution during titration can
safety concerns, if any, associated with its use. It is the
reduce this problem.
responsibility of the user of this standard to establish appro-
5.2 The ground glass joints of the flask and the air con-
priate safety and health practices and determine the applica-
denser must always be rinsed into the flask with hydrolyzing
bility of regulatory limitations prior to use.
solutionatthepointofhydrolysisandbeforetitration.Thiswill
prevent erroneous results from material that may have refluxed
2. Referenced Documents
into the joint.
2.1 ASTM Standards:
D817 Test Methods of Testing CelluloseAcetate Propionate
6. Apparatus
and Cellulose Acetate Butyrate
D871 Test Methods of Testing Cellulose Acetate
6.1 Titrator, equipped with Glass Electrode, or equivalent.
6.2 Heating/Stirring Module, six-place.
3. Summary of Test Method
3.1 The cellulose ester is dissolved in pyridine and the 6.3 Heating/Stirring Block, cut from polished-finish alumi-
hydroxyl sites on the cellulose ester are acetylated with acetic
num block to fit stirrer in 7.2 (see Fig. 1 for dimensions).
anhydride in the presence of basic catalyst, 1-methylimidazole.
6.4 Stirrer, six place.
The excess acetic anhydride is hydrolyzed and the resulting
acetic acid is titrated with sodium hydroxide. An automatic 6.5 Magnetic Stirrers, size 25 mm and 50 mm.
titrator dispenses the titrant, potentiometrically determines the
6.6 Stirring Bar.
endpoint, and calculates the percent hydroxyl on the cellulose
6.7 Flask and Air Condenser, (see Fig. 2 for dimensions).
ester based on a blank determination.
6.8 Bottle-Top Dispensers, capable of dispensing 20 mL, 35
4. Significance and Use
mL, and 50 mL, or equivalent.
4.1 This test method provides a simpler means for the
6.9 Analytical Balance, capable of weighing 250 g to the
determination of the hydroxyl content of cellulose esters than
fourth decimal place.
This test method is under the jurisdiction of ASTM Committee D01 on Paint
6.10 Analytical Balance, capable of weighing 1000 g to the
and Related Coatings, Materials, andApplications and is the direct responsibility of
second decimal place.
Subcommittee D01.36 on Cellulose and Cellulose Derivatives.
Current edition approved June 1, 2007. Published August 2007. Originally
approved in 1996. Last previous edition approved in 2001 as D5897 – 96 (2001).
DOI: 10.1520/D5897-96R07.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Titrator and instruction manual such as Mettler DL77 equipped with DG-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 115-SC glass electrode available from Mettler Toledo Inc., 69 Princeton-
Standards volume information, refer to the standard’s Document Summary page on Hightestown, P.O. Box 71, Hightestown, NJ 08520 has been found suitable for this
the ASTM website. purpose.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5897 − 96 (2007)
FIG. 1 Heating/Stirring Block Dimensions
7. Reagents and Materials
7.1 Purity of Reagents—American Chemical Society re-
agent grade chemicals shall be used throughout this test unless
otherwise indicated.
7.2 Pyridine.
7.3 Acetic Anhydride.
7.4 Acetylating Solution—115 6 0.50 g of acetic anhydride
per litre of pyridine. The container needs to be equipped with
20-mL buret. The shelf-life of this solution is 5 days.
7.5 Dimethylformamide.
7.6 Deionized Water, purified to 18.3 MΩ resistance.
7.7 Hydrolyzing Solution—Mix 600 mL
dimethylformamide, 300 mL pyridine, and 100 mL water in a
1-L bottle equipped with a bottle top dispenser capable of
dosing 35 mL. Stir for at least 10 min prior to use. The
shelf-life of this solution is 1 month.
7.8 1-Methylimidazole.
7.9 Sucrose.
7.10 Acetone.
7.11 Potassium Acid Phthalate (KHP), National Institute of
Standards and Technology primary standard grade. Store in
FIG. 2 Flask and Air Condensor Dimensions
desiccator, after drying for1hat 105°C (65°C).
7.12 Methanol.
7.13 Sodium Hydroxide, 0.5 N in methanol. This solution
7.15 Potassium Chloride (KCl), 5 M, weigh 37.3 g
has a shelf life of 2 weeks.
(60.3000 g) of KCl into a 100-mL volumetric flask. Dilute to
7.14 Traceable Buffers, pH 4 and pH 7, available from
the mark with purified water. Shake into solution.
National Institute of Standards and Technology.
7.16 1,2-Dichloroethane.
8. Calibration and Standardization
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
8.1 Calibration of the Electrode:
listed by the American Chemical Society, see Analar Standards for Laboratory
NOTE 1—If the electrode is new, perforate the nipple on the rubber cap
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, and soak the electrode in 5 M potassium chloride for 1 h. Store in pH 4
MD. buffer until use.
D5897 − 96 (2007)
8.1.1 Select from the titrator menu the procedure for cali- 9.2.1 Dispense1.0mL1-methylimidazoleand20mLacety-
bration of the electrode. lating solution into the flask containing a spin-type stirring bar.
Set the flask into a heating block at 115 6 5°C.
8.1.2 Add about 50 mL of pH 4 buffer into a titration cup
and lower the electrode into it.
9.2.2 Weigh 0.25 g 6 0.0100 g of sucrose into a weighing
8.1.3 Run the procedure for the titrator to read the correct pan, and the
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