ASTM D817-96(2004)
(Test Method)Standard Test Methods of Testing Cellulose Acetate Propionate and Cellulose Acetate Butyrate
Standard Test Methods of Testing Cellulose Acetate Propionate and Cellulose Acetate Butyrate
SIGNIFICANCE AND USE
Ash content gives an estimate of the inorganic content of cellulose ester samples. The presence of high levels of inorganic content (ash) can be detrimental to the melt stability and optical clarity of a cellulose ester in melt processing or act as a potential source of insolubles when the ester is used in solution.
SCOPE
1.1 These test methods cover procedures for the testing of cellulose acetate propionates and acetate butyrates. These esters may vary widely in composition and properties, so certain of the procedures can be used only in the ranges of composition where they are suitable.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 The test procedures appear in the following sections:SectionsAcetyl Propionyl or Butyryl ContentsAcetyl Content, ApparentAcidity, FreeAshColor and HazeHeat StabilityHydroxyl ContentHydroxyl Content, PrimaryIntrinsic ViscosityMoisture Content-Sulfur or Sulfate ContentViscosity-Limiting Viscosity Number
1.4 This standard does not purport to address 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.
1.4 The test methods described in the following to cover the determination of the saponification value of the sample calculated as percentage of apparent acetyl, equivalent weight 43. This value is required in the calculation of acetyl and propionyl or butyryl contents in .
1.5 The test method used should be specified or agreed upon. The choice depends on the propionyl or butyryl content and the physical condition of the sample. Ordinarily, Test Method A is recommended for samples having less than about 35 % propionyl or butyryl and Test Method B for samples having more than that amount.
1.6 The test methods described in the following Sections to cover the determination of acetyl and propionyl or butyryl contents of cellulose mixed esters by calculation from the apparent acetyl content, determined in accordance with Sections to , and the molar ratio of acetyl and propionyl or butyryl, determined in accordance with Sections to . The molar ratio of acetyl and propionyl or butyryl is determined by saponifying, acidifying, vacuum distilling off the mixture of acids, and determining the distribution ratio of the acids between n-butyl acetate and water. The distribution ratios are also determined for acetic, propionic, and butyric acids, using samples of known high purity, and the molar ratio of the acids in the sample is calculated from these values.
1.7 The saponification conditions are varied depending on the propionyl or butyryl content of the sample. Use Procedure A (Section ) for samples containing less than about 35 % propionyl or butyryl, and use Procedure B (Section ) for samples containing more than that amount.
1.8 Analyses for combined acetic, propionic, and butyric acids may be done by gas chromatographic methods. Difficulties encountered include ghosting in the columns, variation of factors with composition, and inconsistencies in the use of pure acids as standards. When such methods are used for this purpose, they shall be cross checked with the following partition method using suitable check batches to establish accuracy.
1.9 This test method is applicable to pyridine-soluble cellulose esters and is especially useful when the hydroxyl content is low. (Samples containing plasticizer may be analyzed directly by this test method because the plasticizer is removed during washing of the carbanilate).
1.10 A preferred method is available in Test Method D 5897.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D 817 – 96 (Reapproved 2004)
Standard Test Methods of Testing
Cellulose Acetate Propionate and Cellulose Acetate
Butyrate
This standard is issued under the fixed designation D 817; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 5897 TestMethodforDeterminationofPercentHydroxyl
onCelluloseEstersbyPotentiometricTitration—Alternative
1.1 These test methods cover procedures for the testing of
Method
cellulose acetate propionates and acetate butyrates. These
2.2 ASTM Adjuncts:
esters may vary widely in composition and properties, so
Color and Haze Apparatus
certain of the procedures can be used only in the ranges of
composition where they are suitable.
3. Reagents
1.2 The values stated in SI units are to be regarded as the
3.1 Purity of Reagents—Reagent grade chemicals shall be
standard. The values given in parentheses are for information
used in all tests. Unless otherwise indicated, it is intended that
only.
all reagents shall conform to the specifications of the Commit-
1.3 The test procedures appear in the following sections:
tee onAnalytical Reagents of theAmerican Chemical Society,
Sections
where such specifications are available. Other grades may be
Acetyl Propionyl or Butyryl Contents 28-37
Acetyl Content, Apparent 18-27
used, provided it is first ascertained that the reagent is of
Acidity, Free 12-17
sufficiently high purity to permit its use without lessening the
Ash 7-10
accuracy of the determination.
Color and Haze 77-81
Heat Stability 57-65
Hydroxyl Content 38-44
4. Conditioning
Hydroxyl Content, Primary 46-50
4.1 Conditioning—Condition the test specimens at 23 6
Intrinsic Viscosity 67-71
Moisture Content 5-6
2°C(73.4 63.6°F)and50 65 %relativehumidityfornotless
Sulfur or Sulfate Content 51-56
than 40 h prior to test in accordance with Procedure A of
Viscosity 74-75
Practice D 618, for those tests where conditioning is required.
Limiting Viscosity Number 67-71
In cases of disagreement, the tolerances shall be 6 1°C
1.4 This standard does not purport to address the safety
(61.8°F) and 62 % relative humidity.
concerns, if any, associated with its use. It is the responsibility
4.2 Test Conditions—Conduct tests in the Standard Labora-
of the user of this standard to establish appropriate safety and
tory Atmosphere of 23 6 2°C (73.4 6 3.6°F) and 50 65%
health practices and determine the applicability of regulatory
relative humidity, unless otherwise specified in the test meth-
limitations prior to use.
ods. In cases of disagreements, the tolerances shall be 61°C
(61.8°F) and 6 2 % relative humidity.
2. Referenced Documents
2.1 ASTM Standards:
MOISTURE CONTENT
D 618 Practice for Conditioning Plastics for Testing
5. Procedure
D 1343 Test Method for Viscosity of Cellulose Derivatives
by Ball-Drop Method
5.1 Transfer about5gofthe sample to a tared, low,
D 2929 Test Method for Sulfur Content of Cellulosic Ma-
wide-form weighing bottle and weigh to the nearest 0.001 g.
terials by X-Ray Fluorescence
Dry in an oven for2hat105 6 3°C. Remove the bottle from
the oven, cover, cool in a desiccator, and weigh.
These test methods are under the jurisdiction of ASTM Committee D01 on
Paint and Related Coatings, Materials, and Applications and are the direct Available from ASTM International Headquarters. Order Adjunct No.
responsibility of Subcommittee D01.36 on Cellulose and Cellulose Derivatives. ADJD0817.
Current edition approved June 1, 2004. Published June 2004. Originally Reagent Chemicals, American Chemical Society Specifications, American
approved in 1944. Last previous edition approved in 1996 as D 817 – 96. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Analar Standards for Laboratory
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Standards volume information, refer to the standard’s Document Summary page on and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
the ASTM website. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 817 – 96 (2004)
6. Calculation 12.3 Phenolphthalein Indicator Solution (1 g/100 mL)—
Dissolve 1 g phenolphthalein in 100 mL of ethyl alco-
6.1 Calculate the percentage of moisture as follows:
hol (95 %).
Moisture, % 5 ~A/B! 3 100 (1)
12.4 Sodium Hydroxide, Standard Solution (0.01 N)—
Prepare and standardize a 0.01N solution of sodium hydroxide
where:
(NaOH).
A = weight loss on heating, g, and
B = sample used, g.
Test Method A—For Samples Containing Not More than
About 30% Propionyl or Butyryl
ASH
13. Procedure
7. Significance and Use
13.1 Shake5gofthesample,correctedformoisturecontent
7.1 Ash content gives an estimate of the inorganic content
if necessary, in a 250-mL Erlenmeyer flask with 150 mL of
of cellulose ester samples. The presence of high levels of
freshly boiled, cold water. Stopper the flask and allow it to
inorganic content (ash) can be detrimental to the melt stability
stand for 3 h. Filter off the cellulose ester and wash it with
and optical clarity of a cellulose ester in melt processing or act
water. Titrate the combined filtrate and washings with 0.01 N
as a potential source of insolubles when the ester is used in
NaOH solution, using phenolphthalein indicator solution.
solution.
13.2 Runablankdeterminationonthewater,usingthesame
volume as was used in extracting the sample.
8. Procedure
8.1 Dry the sample for2hat105 6 3°C and weigh 10 to 50
14. Calculation
g, to the nearest 0.01 to 0.1 g, depending on its ash content and
14.1 Calculate the percentage of acidity as free acetic acid
the accuracy desired. Burn directly over a flame in a 100-mL
as follows:
tared platinum crucible that has been heated to constant weight
Free acetic acid, % 5 @~A 2B!C 3 0.06]/W 3 100 (3)
$ %
and weighed to the nearest 0.1 mg.Add the sample in portions
if more than 10 g is taken. The sample should burn gently and
where:
the portions should be added as the flame subsides. Continue
A = NaOH solution used to titrate the sample, mL,
heating with a burner only as long as the residue burns with a
B = NaOH solution used to titrate the blank, mL,
flame. Transfer the crucible to a muffle furnace and heat at 550
C = normality of the NaOH solution, and
to 600°C for 3 h, or longer if required, to burn all the carbon. W = sample used, g.
Allowthecrucibletocoolandthentransferit,whilestillwarm,
Test Method B—For Samples Containing More than About
to a desiccator. When the crucible has cooled to room tem-
7% Propionyl or Butyryl and Particularly Suitable for
perature, weigh accurately to the nearest 0.1 mg.
Samples Containing More than 30% Propionyl or Butyryl
9. Calculation
15. Procedure
9.1 Calculate the percentage of ash as follows:
15.1 Dissolve 10.0 g of the sample, corrected for moisture
Ash, % 5 A/B 3 100 (2)
~ !
content if necessary, in 200 mL of neutral acetone plus 20 mL
of water. When completely dissolved, add 50 mL of water and
where:
shake well to precipitate the ester in a finely divided form.Add
A = ash, g, and
3 drops of methyl red indicator solution and titrate to a
B = sample used, g.
lemon-yellow end point and 0.01 N NaOH solution.
15.2 Make a blank determination on the reagents.
10. Precision and Bias
10.1 No statement on bias can be made as no reference
16. Calculation
material is available as a standard.
16.1 Calculate the free acid content as acetic acid as
directed in Section 14.
FREE ACIDITY
17. Precision and Bias
11. Significance and Use
17.1 No statement on bias can be made as no reference
11.1 Free acidity is a measure of unesterified organic acid in
material is available as a standard.
the ester. The presence of high levels of free acid is potentially
detrimental to melt processing of the ester and can impact the
APPARENTACETYL CONTENT
odor of the ester.
18. Scope
12. Reagents
18.1 The test methods described in the following 20 to 26
12.1 Acetone, neutral. cover the determination of the saponification value of the
12.2 Methyl Red Indicator Solution (0.4 g/L)—Dissolve 0.1 sample calculated as percentage of apparent acetyl, equivalent
g of methyl red in 3.72 mL of 0.1000 N NaOH solution and weight 43. This value is required in the calculation of acetyl
dilute to 250 mL with water. Filter if necessary. and propionyl or butyryl contents in 36.1.
D 817 – 96 (2004)
18.2 The test method used should be specified or agreed 22. Procedure
upon. The choice depends on the propionyl or butyryl content
22.1 Dry the ground well-mixed sample in weighing bottle
and the physical condition of the sample. Ordinarily, Test
for2hat105 6 3°C and weigh 1.9 6 0.05 g of the dried
MethodAis recommended for samples having less than about
sample by difference to the nearest 1 mg into a 500-mL
35 % propionyl or butyryl and Test Method B for samples
Erlenmeyer flask. Prepare a blank by drying approximately 3.8
having more than that amount.
gofpotassiumacidphthalateandweighingitbydifferenceinto
a flask as described above. Carry the blank through the entire
19. Significance and Use
procedure.
19.1 Apparent acetyl content is a measure of the saponifi-
NOTE 1—Potassium acid phthalate is used so that the concentration of
cation value of the ester. Apparent acetyl value is required in
the NaOH in contact with the solvent in the blank will be approximately
the calculation of acetyl, propionyl, and butyryl content in
the same as that in contact with the sample and so that the titration of the
36.1.
blank will be approximately the same as the titration of the sample, thus
avoiding errors caused by using a different buret for the titration of the
blank and the sample or by refilling the 15-mLburet. If desired, however,
Test Method A—For Samples Containing Less than About
the potassium acid phthalate may be omitted.
35% Propionyl or Butyryl
22.2 For acetone-soluble sample, put the sample into solu-
20. Apparatus
tion as follows: Add 150 mL of acetone and 5 to 10 mL of
water and swirl to mix. Stopper the flask and allow it to stand
20.1 Weighing Bottle, glass-stoppered, 15-mL capacity,
with occasional swirling until solution is complete. Solution
25-mm diameter by 50 mm high.
may be hastened by magnetic stirring or by any suitable
20.2 Tray, copper or aluminum, approximately 137 mm
mechanical shaking that will provide a gentle rocking type of
square, containing 25 compartments 25 mm square. Each
agitation to avoid splashing the solution on the stopper. It is
compartment shall have the correct dimensions to contain one
essential that complete solution be effected.
weighing bottle.The entire tray shall fit inside a desiccator and
22.3 For acetone-insoluble samples of low propionyl or
should have a basket-type handle to facilitate the introduction
butyryl content, dissolve the sample by either of the following
and removal of the tray (convenient but not essential).
two methods:
20.3 Buret, automatic zero, 35-mL, 25-mL bulb, stem
22.3.1 Gently rotate the flask by hand to distribute and
graduated from 25 to 35 mL in 0.05-mL increments; or pipet,
spread the sample in a thin layer over the bottom of the flask.
automatic zero, 30-mL for NaOH solution (40 g/L).
Add 70 mL of acetone to the flask and swirl gently until the
20.4 Buret, automatic zero, 15-mL, 10-mL bulb, stem
sample particles are completely wetted and evenly dispersed.
graduated from 10 to 15 mL in 0.05-mL increments, for 1 N
Stopper the flask and allow it to stand undisturbed for 10 min.
H SO .
2 4
Carefully add 30 mL of dimethyl sulfoxide from a graduate to
20.5 Buret, 5-mL, in 0.01 or 0.1-mL divisions, for back
the flask, pouring the solvent down the sides of the flask to
titration with 0.1 N NaOH solution.
wash down any sample particles clinging to the side. Stopper
20.6 Magnetic Stirrer, for single flask.
the flask and allow it to stand with occasional swirling until
20.7 Magnetic Stirrer, capacity twelve or more flasks.
solution is complete. Magnetic stirring or gentle mechanical
20.8 Stirring Bars, stainless steel Type 416, length 50 mm,
agitation that will not splash the solution is recommended.
diameter 5 to 6 mm or equivalent, dimensions not critical.
When solution appears to be complete, add 50 mL of acetone
and swirl or stir for 5 min. Proceed in accordance with 22.4.
21. Reagents
22.3.2 Dimethyl sulfoxide is the preferred solvent, but if it
21.1 Acetone—Add one 30-mL portion of 1.0 N NaOH
is not available, spread the sample in a thin layer over the
solution to a mixture of 150 mLacetone and 100 mLhot water,
bottom of the flask, add 15 mL of acetone, swirl to wet the
allow to stand with frequent swirling for 30 min, and titrate
particles with acetone, stopper the flask, and allow the mixture
with 1.0 N H SO .Add another 30-mLportion of 1.0 N NaOH
2 4 to stand undisturbed for 20 min. Add 75 mL of pyridine
solution to 100 mLof hot water, allow to stand for 30 min, and
without shaking or swirling and allow the mixture to stand for
titrate as above. The difference between the two titrations shall
10 min. Heat the solution just to boiling and swirl or stir for 5
not exceed 0.05 mL.
min. Again heat to boiling and swirl or stir for 10 min.
21.2 Dimethyl Sulfoxide.
Continue to heat and stir until the mixture is homogeneous and
21.3 Pyridine.
all large gel masses are broken down into individual highly
21.4 SodiumHydroxideSolution(40g/L)—Dissolve 40 g of
swollen particles. When these highly swollen gel particles are
sodium hydroxide (NaOH) in water and dilute to 1 L.
well dispersed and are not fused together in large gel masses,
21.5 Sodium Hydroxide, Standard Solution (0.1 N)— no further heating is necessary. Cool the flask, add 30 mL of
Prepare and standardize a 0.1 N solution of NaOH.
acetone, and swirl or stir for 5 min.
21.6 Sulfuric Acid Standard (1.0 N)—Prepare and stan- 22.4 Add 30 mL of NaOH solution (40 g/L) with constant
dardize a 1.0 N solution of sulfuric acid (H SO ).
swirling or stirring to the solution of the sample and also to the
2 4
21.7 Phenolphthalein Indicator Solution (1 g/100 mL)— blank. Use of a magnetic stirrer is recommended (Note 2). It is
Dissolve1gof phenolphthalein in 100 mL of ethyl alcohol absolutely necessary that a finely divided precipitate of regen-
(95 %). erated cellulose, free of lumps, be obtained. Stopper the flask
...
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