ASTM D1348-94(1998)
(Test Method)Standard Test Methods for Moisture in Cellulose
Standard Test Methods for Moisture in Cellulose
SCOPE
1.1 These test methods cover the determination of moisture in cellulose using two oven-drying procedures and one Karl Fischer procedure.
1.2 The test procedures appear in the following order: Sections Test Method A-Specimen Weighed in Oven 4 to 10 Test Method B-Specimen Weighed Outside of Oven 11 to 17 Test Method C-Karl Fischer Method 18 to 25
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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.
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Standards Content (Sample)
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Designation: D 1348 – 94 (Reapproved l998)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Methods for
Moisture in Cellulose
This standard is issued under the fixed designation D 1348; 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 3.1.2 Except for those samples taken in an atmosphere with
which the sample is in equilibrium, the moisture content of the
1.1 These test methods cover the determination of moisture
sample will begin to change immediately after it is removed
in cellulose using two oven-drying procedures and one Karl
from its original surroundings. This change can be reduced by
Fischer procedure.
taking extra layers of sheeted material and discarding a few
1.2 The test procedures appear in the following order:
layers from the top and bottom before weighing, folding, or
Sections
rolling the sample to reduce the exposed area, and by placing
Test Method A—Specimen Weighed in Oven 4-10
Test Method B—Specimen Weighed Outside of Oven 11-17
small samples in cans or bottles and protecting larger samples
Test Method C—Karl Fischer Method 18-25
by wrapping in rubber sheets, moistureproof cellophane, or
1.3 The values stated in SI units are to be regarded as the other protective wrappings. These means do not provide
standard. The values given in parentheses are for information
continuous protection, and the test samples should be weighed
only. as soon as possible.
1.4 This standard does not purport to address all of the
3.1.3 When possible, bulk samples should be taken. These
safety concerns, if any, associated with its use. It is the samples should weigh from 100 to 300 g (3.5 to 10.5 oz), the
responsibility of the user of this standard to establish appro-
larger samples being taken when the moisture content is low or
priate safety and health practices and determine the applica- variable. Following the initial weighing, the bulk samples
bility of regulatory limitations prior to use.
should be cut up or torn into small pieces and then mixed and
allowed to stand overnight or longer in a sealed container to
2. Significance and Use
obtain moisture equilibrium before weighing out test speci-
2.1 These test methods determine the amount of moisture
mens; or the sample may be allowed to come to approximate
contained in a cellulose sample which determines the amount
equilibrium with the laboratory air and reweighed to determine
of bone dry cellulose present in a sample. The actual amount of
moisture change before weighing test specimens. The latter
cellulose in a sample is an essential entity when using cellulose
procedure is recommended since it permits routine weighing of
as a starting material for the production of cellulose deriva-
samples without the use of special weighing bottles or boxes,
tives.
and a series of accumulated samples can be weighed simulta-
neously. Predrying is very desirable on samples with a high
3. Sampling
moisture content (more than 5 % above equilibrium value).
3.1 Cellulose in a variety of forms is sampled for moisture,
When samples have been predried, calculate the moisture lost,
and no single set of directions can be given that is applicable
as follows:
to all types of cellulose material. The following general
R 5 M – A/A 3 100 (1)
@ #
considerations should be borne in mind.
3.1.1 Cellulose, either in compact form, such as wood,
where:
sheeted pulp or paper, baled cotton or baled staple rayon, or in R 5 moisture, air-dry sample basis, %,
loose form such as sawdust or chips, may have an appreciably M 5 original mass of the sample, g, and
A 5 air-dry mass of sample, g.
different moisture content in sections lying relatively close
3.1.4 The apparent moisture subsequently observed when
together. In order to secure representative samples, therefore, a
testing a predried sample must be calculated on the basis of the
bulk sample should be made up of small portions taken from
original sample mass in order to get the original moisture
various parts of the lot and having the proper proportion of
content. Calculate the original mass of the air-dried sample as
edge and center material.
follows:
Original sample mass, g 5 @A 3 ~100 1 R!#/100 (2)
These test methods are under the jurisdiction of ASTM Committee D-1 on Paint
NOTE 1—Example—If 1000 g (35 oz) of bulk (wet) sample on exposure
and Related Coatings, Materials, and Applications, and are the direct responsibility
to air lose 200 g (7 oz) of water, the apparent moisture content is 20 % and
of Subcommittee D01.36 on Cellulose and Cellulose Derivatives.
equivalent regain is 25 %. If an 8-g (0.28-oz) specimen of the air-dry
Current edition approved Oct. 15, 1994. Published December 1994. Originally
published as D 1348 – 54. Last previous edition D 1348 – 89.
NOTICE:¬This¬standard¬has¬either¬been¬superceded¬and¬replaced¬by¬a¬new¬version¬or¬discontinued.¬
Contact¬ASTM¬International¬(www.astm.org)¬for¬the¬latest¬information.¬
D 1348
material is taken for drying in the oven, the original mass is 8 3 1.25 5 10
7.2 Dry the specimen for2hat105 6 3°C, passing a
g (0.35 oz).
current of dry air into the bottom of the oven during the drying
period. (If dry air is not forced through the oven, dry for 4 h.)
TEST METHOD A—SPECIMEN WEIGHED IN OVEN
NOTE 4—Reproducible but less accurate values (under unfavorable
4. Scope
conditions the absolute error may be as high as 1 %) will be obtained if the
current of predried air is omitted. Since the error will be identical for all
4.1 This test method for moisture determination is appli-
similar samples in the oven at one time, the results obtained in these cases
cable to a variety of cellulose types and can be used in most
will be comparable. The magnitude of error will vary directly with the
cases where a sample does not contain nonaqueous material
relative humidity of the air entering the oven and with the equilibrium
volatile at 105°C. The test method can be used for samples
moisture content of samples at low relative humidity. Thus, the error will
having either high or low moisture content.
be higher on regenerated cellulose than on wood pulp or cotton, but it still
would not usually be greater than 0.2 %, absolute.
5. Summary of Test Method
7.3 At the end of the specified period, cut off the flow of air
5.1 The specimen is heated to constant mass at 105°C in a
and weigh the specimen without removing it from the oven.
ventilated gravity-convection oven, in a current of dry air, for
Continue drying for ½ h longer, with the normal air flow, and
a period of 2 h. If no dry air is used, the specimen is heated for
reweigh the specimen. Repeat the drying and weighing until
4h.
the mass loss between successive weighings is not more than
0.005 g, or until the specimen shows a gain in mass. Designate
6. Apparatus
this mass as D.
6.1 Oven with Built-In Weighing Equipment—Such an oven
7.4 Additional specimens should not be placed in the oven
employs a system of tared containers mounted on a table or
until the first specimens have attained constant mass.
track that can be rotated to bring specimens to a specific point
in the oven, where the specimen and container can be placed on
8. Calculation
a hook or a tray connected to an outside balance. The oven
8.1 Calculate moisture, as measured in the oven, as follows:
must be capable of maintaining a constant temperature of 105
Moisture content, % 5 @~M – D/M# 3 100 (3)
6 3°C, with an average temperature of 105°C; continuous
Moisture, dry basis ~regain!,% 5 @~M – D!/D# 3 100 (4)
operation below 105°C is not satisfactory.
NOTE 2—In ovens having heating elements at the bottom only, and no
where:
cross circulation, the temperature of the lower shelves should be checked
M 5 original mass of specimen, and .
before they are used.
D 5 mass of oven-dry specimen.
6.2 Dry Air Stream—Air, dried by passing through silica
9. Report
gel, aluminum oxide, concentrated sulfuric acid, or other
9.1 Report the moisture in the cellulose on either or both of
suitable drying agent, should be passed through the oven at a
the following bases:
rate sufficient to effect a complete change once every 2 min. If
9.1.1 On the basis of the original sample, when it is termed
the air is dried by means of concentrated sulfuric acid,
“moisture content,” “moisture as received,” or “moisture as is”
adequate traps must be provided. The use of sulfuric acid
basis.
followed by perchloric drying agents should be avoided.
9.1.2 On the basis of the oven-dry cellulose, when it is
6.3 Shallow Glass Weighing Bottles—Bottles with ground
termed “moisture, dry basis” or “moisture regain.”
glass stoppers, measuring 30 mm high, and having a capacity
9.2 In order to avoid confusion always use the appropriate
of 30 mL.
term.
6.4 Seamless Metal Weighing Boxes, having a wall height,
when open, preferably not over 25.4 mm (1 in.).
10. Precision and Bias
7. Procedure
10.1 Precision:
10.1.1 Statistical analysis of intralaboratory (repeatability)
7.1 Remove the basket, shallow pan, or other container
test results on samples containing 5 to 15 % moisture indicates
supplied for use with the oven (Note 3). Weigh the container
a precision of 60.14 % at the 95 % confidence level.
and place in it a specimen of 10 to 50 g (0.35 to 1.75 oz)
10.1.2 Statistical analysis of interlaboratory (reproducibil-
weighed to the nearest 0.005 g. Designate this mass as M. Place
ity) test results on samples containing 5 to 15 % moisture
the specimen in a tared container in the oven in such a manner
indicates a precision of 60.2 % at the 95 % confidence level.
that it can be reweighed without removal from the oven.
10.2 Bias—No justifiable statement can be made on the bias
NOTE 3—Experience has shown that when yarn and fiber specimens are
of the procedure for measuring moisture in cellulose because
left in comparatively deep weighing bottles in the oven, relatively
no suitable reference material exists.
discordant results are obtained and the drying period is unnecessarily long.
To avoid these difficulties specimens should be dried in containers that
TEST METHOD B—SPECIMEN WEIGHED OUTSIDE
give the cellulose free access to the air. For fibrous or bulky materials to
OF OVEN
be weighed in an oven, use containers such as open wire grills or baskets.
For small specimens to be weighed out of the oven, use wire screen
11. Scope
baskets that will fit in weighing bottles, but if the specimen is powdery or
11.1 The scope and application of this test method are the
tends to shed lint or fine short fibers, use a small weighing bottle or metal
boxes. same as those of Test Method A (see Section 4).
NOTICE:¬This¬standard¬has¬either¬been¬superceded¬and¬replaced¬by¬a¬new¬version¬or¬discontinued.¬
Contact¬ASTM¬International¬(www.astm.org)¬for¬the¬latest¬information.¬
D 1348
12. Summary of Test Method 15. Calculation
12.1 See Test Method A (Section 5). 15.1 Calculate moisture, as measured outside of the oven, as
follows:
13. Apparatus
Moisture content, % @~M – D!/~M – T!# 3 100 (5)
13.1 Oven Without Built-In Weighing Equipment—Any
Moisture, dry basis, ~regain!,% 5 @~M – D!/~D – T!# 3 100 (6)
ventilated oven capable of maintaining a constant temperature
of 105 6 3°C, with an average temperature of 105°C;
where:
continuous operation below 105°C is not satisfactory.
M 5 original mass of the specimen (plus basket) and
weigh- ing bottle,
NOTE 5—In ovens having heating elements at the bottom only, and no
D 5 oven-dry mass of the specimen (plus basket), and
cross circulation, the temperature of the lower shelves should be checked
T 5 mass of the empty weighing bottle (plus basket).
before they are used.
13.2 Dry Air Stream—See 6.2. 16. Report
13.3 Shallow Glass Weighing Bottles—See 6.3.
16.1 Report the moisture in the cellulose as directed in
13.4 Seamless Metal Weighing Boxes—See 6.4.
Section 9.
13.5 Weighing Bottles, glass with ground-glass stoppers,
17. Precision and Bias
approximately 40 mm wide and 80 mm high.
13.6 Wire Baskets—Fitted baskets for weighing bottles
17.1 See Section 10.
made from approximately 15-mesh stainless steel, Monel, or
TEST METHOD C—KARL FISCHER METHOD
other suitable screen. The height and depth of the basket will be
determined by the weighing bottle used; the basket must slide
18. Scope
into and out of the bottle without binding. The basket should
18.1 This test method covers the determination of moisture
have a solid bottom, but no top is required.
in cellulose by titration with Karl Fischer reagent. The test
method is applicable to all types and forms of cellulose. It is
14. Procedure
especially useful with samples containing nonaqueous material
14.1 If the sample is free of lint, dust, or short fibers, place
volatile at 110°C, since such substances interfere in the
approximately 10 g (0.35 oz) of the sample into a previously
oven-drying methods. Anhydrides, alkalies, and large amounts
dried and desiccated wire basket (Note 2) contained in a dry
of aldehydes and ketones interfere.
weighing bottle. Stopper the weighing bottle, and weigh to the
18.2 The Karl Fischer titration method is especially valu-
nearest 0.001 g. Designate this mass as M. Remove the basket
able where only small amounts of samples are available. The
containing the specimen from the weighing bottle and place the
procedure lends itself to multiple determinations.
basket, weighing bottle, and stopper in the oven. If the
18.3 It is essential that the Karl Fischer reagent, standard
specimen includes powder-like material, transfer the specimen
water solution, and anhydrous methanol be protected from
directly into a small weighing bottle or can. Stopper the bottle
atmospheric moisture at all times. During the titration a stream
and weigh to the nearest 0.001 g (M). Remove the stopper from
of dry air or nitrogen will protect the contents of the titration
the bottle and place the bottle containing the specimen and the
flask from atmospheric moisture pick-up.
stopper in the oven.
19. Summary of Test Method
14.2 Dry for2hat105 6 3°C, passing a current of dry air
into the bottom of the oven during the drying period. (If dry air
19.1 An excess of Karl Fischer reagent is added to the
is not forced through the oven, dry for 4 h.)
specimen suspended in anhydrous methanol. After shaking for
14.3 At the end of the specified period, quickly place the
15 to 20 min to extract the moisture, the excess is back-titrated
basket and specimen in the weighing bottle again and st
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