ASTM D570-98(2018)
(Test Method)Standard Test Method for Water Absorption of Plastics
Standard Test Method for Water Absorption of Plastics
SIGNIFICANCE AND USE
3.1 This test method for rate of water absorption has two chief functions: first, as a guide to the proportion of water absorbed by a material and consequently, in those cases where the relationships between moisture and electrical or mechanical properties, dimensions, or appearance have been determined, as a guide to the effects of exposure to water or humid conditions on such properties; and second, as a control test on the uniformity of a product. This second function is particularly applicable to sheet, rod, and tube arms when the test is made on the finished product.
3.2 Comparison of water absorption values of various plastics can be made on the basis of values obtained in accordance with 7.1 and 7.4.
3.3 Ideal diffusion of liquids3 into polymers is a function of the square root of immersion time. Time to saturation is strongly dependent on specimen thickness. For example, Table 1 shows the time to approximate time saturation for various thickness of nylon-6.
3.4 The moisture content of a plastic is very intimately related to such properties as electrical insulation resistance, dielectric losses, mechanical strength, appearance, and dimensions. The effect upon these properties of change in moisture content due to water absorption depends largely on the type of exposure (by immersion in water or by exposure to high humidity), shape of the part, and inherent properties of the plastic. With nonhomogeneous materials, such as laminated forms, the rate of water absorption may be widely different through each edge and surface. Even for otherwise homogeneous materials, it may be slightly greater through cut edges than through molded surfaces. Consequently, attempts to correlate water absorption with the surface area must generally be limited to closely related materials and to similarly shaped specimens: For materials of widely varying density, relation between water-absorption values on a volume as well as a weight basis may need to be considered.
SCOPE
1.1 This test method covers the determination of the relative rate of absorption of water by plastics when immersed. This test method is intended to apply to the testing of all types of plastics, including cast, hot-molded, and cold-molded resinous products, and both homogeneous and laminated plastics in rod and tube form and in sheets 0.13 mm (0.005 in.) or greater in thickness.
1.2 The values given in SI units are to be regarded as standard. The values stated in parentheses are for information only.
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 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: D570 − 98 (Reapproved 2018)
Standard Test Method for
Water Absorption of Plastics
This standard is issued under the fixed designation D570; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope conditions on such properties; and second, as a control test on
the uniformity of a product. This second function is particu-
1.1 Thistestmethodcoversthedeterminationoftherelative
larly applicable to sheet, rod, and tube arms when the test is
rate of absorption of water by plastics when immersed. This
made on the finished product.
test method is intended to apply to the testing of all types of
plastics, including cast, hot-molded, and cold-molded resinous 3.2 Comparison of water absorption values of various plas-
products, and both homogeneous and laminated plastics in rod tics can be made on the basis of values obtained in accordance
and tube form and in sheets 0.13 mm (0.005 in.) or greater in with 7.1 and 7.4.
thickness. 3
3.3 Ideal diffusion of liquids into polymers is a function of
1.2 The values given in SI units are to be regarded as the square root of immersion time. Time to saturation is
standard. The values stated in parentheses are for information strongly dependent on specimen thickness. For example, Table
only. 1 shows the time to approximate time saturation for various
thickness of nylon-6.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.4 The moisture content of a plastic is very intimately
responsibility of the user of this standard to establish appro-
related to such properties as electrical insulation resistance,
priate safety, health, and environmental practices and deter-
dielectric losses, mechanical strength, appearance, and dimen-
mine the applicability of regulatory limitations prior to use.
sions. The effect upon these properties of change in moisture
1.4 This international standard was developed in accor-
content due to water absorption depends largely on the type of
dance with internationally recognized principles on standard-
exposure (by immersion in water or by exposure to high
ization established in the Decision on Principles for the
humidity), shape of the part, and inherent properties of the
Development of International Standards, Guides and Recom-
plastic. With nonhomogeneous materials, such as laminated
mendations issued by the World Trade Organization Technical
forms, the rate of water absorption may be widely different
Barriers to Trade (TBT) Committee.
through each edge and surface. Even for otherwise homoge-
neous materials, it may be slightly greater through cut edges
2. Referenced Documents
than through molded surfaces. Consequently, attempts to
correlatewaterabsorptionwiththesurfaceareamustgenerally
2.1 ISO Standard:
be limited to closely related materials and to similarly shaped
ISO62 Plastics—Determination of Water Absorption
specimens: For materials of widely varying density, relation
between water-absorption values on a volume as well as a
3. Significance and Use
weight basis may need to be considered.
3.1 This test method for rate of water absorption has two
chief functions: first, as a guide to the proportion of water
absorbed by a material and consequently, in those cases where
therelationshipsbetweenmoistureandelectricalormechanical
properties, dimensions, or appearance have been determined,
as a guide to the effects of exposure to water or humid
ThistestmethodisunderthejurisdictionofASTMCommitteeD20onPlastics
and is the direct responsibility of Subcommittee D20.50 on Durability of Plastics. Additional information regarding diffusion of liquids in polymers can be found
Current edition approved Aug. 1, 2018. Published August 2018. Originally in the following references: (1) Diffusion, Mass Transfer in Fluid Systems,E.L.
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approved in 1940. Last previous edition approved in 2010 as D570-98 (2010) . Cussler, Cambridge University Press, 1985, ISBN 0-521-29846-6, (2) Diffusion in
DOI: 10.1520/D0570-98R18. Polymers, J. Crank and G.S. Park, Academic Press, 1968, and (3) “Permeation,
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St., Diffusion, and Sorption of Gases and Vapors,” R.M. Felder and G.S. Huvard, in
4th Floor, New York, NY 10036, http://www.ansi.org. Methods of Experimental Physics, Vol 16C, 1980, Academic Press.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D570 − 98 (2018)
TABLE 1 Time to Saturation for Various Thickness of Nylon-6
5.7 The dimensions listed in the following table for the
Typical Time to 95 % various specimens shall be measured to the nearest 0.025 mm
Thickness, mm
Saturation, h
(0.001 in.). Dimensions not listed shall be measured within 0.8
1 100 1
mm (6 ⁄32 in.).
2 400
Type of Dimensions to Be Measured to
3.2 1 000
Specimen the
10 10 000
Nearest 0.025 mm (0.001 in.)
25 62 000
Molded disk thickness
Sheet thickness
Rod length and diameter
Tube inside and outside diameter, and
wall thickness
4. Apparatus
6. Conditioning
4.1 Balance—An analytical balance capable of reading
6.1 Three specimens shall be conditioned as follows:
0.0001 g.
6.1.1 Specimens of materials whose water-absorption value
4.2 Oven, capable of maintaining uniform temperatures of
would be appreciably affected by temperatures in the neigh-
50 63°C (122 65.4°F) and of 105 to 110°C (221 to 230°F). borhood of 110°C (230°F), shall be dried in an oven for 24 h
at 50 63°C (122 65.4°F), cooled in a desiccator, and imme-
5. Test Specimen diately weighed to the nearest 0.001 g.
5.1 The test specimen for molded plastics shall be in the
NOTE 2—If a static charge interferes with the weighing, lightly rub the
⁄8 in.) surface of the specimens with a grounded conductor.
form of a disk 50.8 mm (2 in.) in diameter and 3.2 mm (
inthickness.Permissiblevariationsinthicknessare 60.18mm
6.1.2 Specimens of materials, such as phenolic laminated
(60.007 in.) for hot-molded and 60.30 mm (60.012 in.) for
plastics and other products whose water-absorption value has
cold-molded or cast materials.
been shown not to be appreciably affected by temperatures up
to 110°C (230°F), shall be dried in an oven for1hat105to
5.2 ISO Standard Specimen—The test specimen for homo-
110°C (221 to 230°F).
geneous plastics shall be 60 by 60 by 1 mm. Tolerance for the
6.1.3 When data for comparison with absorption values for
60-mm dimension is 62mmand 60.05 mm for the 1-mm
other plastics are desired, the specimens shall be dried in an
thickness.This test method and ISO62 are technically equiva-
oven for 24 h at 50 63°C (122 65.4°F), cooled in a
lent when the test specimen described in 5.2 is used.
desiccator, and immediately weighed to the nearest 0.001 g.
5.3 Thetestspecimenforsheetsshallbeintheformofabar
76.2 mm (3 in.) long by 25.4 mm (1 in.) wide by the thickness
7. Procedure
of the material. When comparison of absorption values with
7.1 Twenty-Four Hour Immersion—The conditioned speci-
molded plastics is desired, specimens 3.2-mm ( ⁄8-in.) thick
mens shall be placed in a container of distilled water main-
should be used. Permissible variations in thickness shall be
tained at a temperature of 23 61°C (73.4 61.8°F), and shall
0.20 mm (60.008 in.) except for materials which have greater
rest on edge and be entirely immersed. At the end of 24, + ⁄2,
standard commercial tolerances.
−0 h, the specimens shall be removed from the water one at a
5.4 Thetestspecimenforrodsshallbe25.4-mm(1-in.)long
time, all surface water wiped off with a dry cloth, and weighed
for rods 25.4 mm in diameter or under and 12.7-mm ( ⁄2-in.)
tothenearest0.001gimmediately.Ifthespecimenis ⁄16in.or
long for larger-diameter rods. The diameter of the specimen
less in thickness, it shall be put in a weighing bottle immedi-
shall be the diameter of the finished rod.
ately after wiping and weighed in the bottle.
5.5 The test specimen for tubes less than 76 mm (3 in.) in
7.2 Two-Hour Immersion—For all thicknesses of materials
inside diameter shall be the full section of the tube and
having a relatively hig
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: D570 − 98 (Reapproved 2010) D570 − 98 (Reapproved 2018)
Standard Test Method for
Water Absorption of Plastics
This standard is issued under the fixed designation D570; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
ε NOTE—Removed ASTM D647 as a referenced document editorially in June 2010.
1. Scope
1.1 This test method covers the determination of the relative rate of absorption of water by plastics when immersed. This test
method is intended to apply to the testing of all types of plastics, including cast, hot-molded, and cold-molded resinous products,
and both homogeneous and laminated plastics in rod and tube form and in sheets 0.13 mm (0.005 in.) or greater in thickness.
1.2 The values given in SI units are to be regarded as standard. The values stated in parentheses are for information only.
1.3 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
NOTE 1—This standard is equivalent to ISO 62.
1.4 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.
2. Referenced Documents
2.1 ISO Standard:
ISO 62 Plastics—Determination of Water Absorption
3. Significance and Use
3.1 This test method for rate of water absorption has two chief functions: first, as a guide to the proportion of water absorbed
by a material and consequently, in those cases where the relationships between moisture and electrical or mechanical properties,
dimensions, or appearance have been determined, as a guide to the effects of exposure to water or humid conditions on such
properties; and second, as a control test on the uniformity of a product. This second function is particularly applicable to sheet,
rod, and tube arms when the test is made on the finished product.
3.2 Comparison of water absorption values of various plastics can be made on the basis of values obtained in accordance with
7.1 and 7.4.
3.3 Ideal diffusion of liquids into polymers is a function of the square root of immersion time. Time to saturation is strongly
dependent on specimen thickness. For example, Table 1 shows the time to approximate time saturation for various thickness of
nylon-6.
3.4 The moisture content of a plastic is very intimately related to such properties as electrical insulation resistance, dielectric
losses, mechanical strength, appearance, and dimensions. The effect upon these properties of change in moisture content due to
water absorption depends largely on the type of exposure (by immersion in water or by exposure to high humidity), shape of the
part, and inherent properties of the plastic. With nonhomogeneous materials, such as laminated forms, the rate of water absorption
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.50 on Durability of Plastics.
Current edition approved April 1, 2010Aug. 1, 2018. Published June 2010August 2018. Originally approved in 1940. Last previous edition approved in 20052010 as
ɛ1
D570 - 98 (2005).(2010) . DOI: 10.1520/D0570-98R10E01.10.1520/D0570-98R18.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Additional information regarding diffusion of liquids in polymers can be found in the following references: (1) Diffusion, Mass Transfer in Fluid Systems, E. L. Cussler,
Cambridge University Press, 1985, ISBN 0-521-29846-6, (2) Diffusion in Polymers, J. Crank and G. S. Park, Academic Press, 1968, and (3) “Permeation, Diffusion, and
Sorption of Gases and Vapors,” R. M. Felder and G. S. Huvard, in Methods of Experimental Physics, Vol 16C, 1980, Academic Press.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D570 − 98 (2018)
TABLE 1 Time to Saturation for Various Thickness of Nylon-6
Typical Time to 95 %
Thickness, mm
Saturation, h
1 100
2 400
3.2 1 000
10 10 000
25 62 000
may be widely different through each edge and surface. Even for otherwise homogeneous materials, it may be slightly greater
through cut edges than through molded surfaces. Consequently, attempts to correlate water absorption with the surface area must
generally be limited to closely related materials and to similarly shaped specimens: For materials of widely varying density,
relation between water-absorption values on a volume as well as a weight basis may need to be considered.
D570 − 98 (2018)
4. Apparatus
4.1 Balance—An analytical balance capable of reading 0.0001 g.
4.2 Oven, capable of maintaining uniform temperatures of 50 6 3°C (122 6 5.4°F) and of 105 to 110°C (221 to 230°F).
5. Test Specimen
5.1 The test specimen for molded plastics shall be in the form of a disk 50.8 mm (2 in.) in diameter and 3.2 mm ( ⁄8 in.) in
thickness. Permissible variations in thickness are 60.18 mm (60.007 in.) for hot-molded and 60.30 mm (60.012 in.) for
cold-molded or cast materials.
5.2 ISO Standard Specimen—The test specimen for homogeneous plastics shall be 60 by 60 by 1 mm. Tolerance for the 60-mm
dimension is 62 mm and 60.05 mm for the 1-mm thickness. This test method and ISO 62 are technically equivalent when the
test specimen described in 5.2 is used.
5.3 The test specimen for sheets shall be in the form of a bar 76.2 mm (3 in.) long by 25.4 mm (1 in.) wide by the thickness
of the material. When comparison of absorption values with molded plastics is desired, specimens 3.2-mm ( ⁄8-in.) thick should
be used. Permissible variations in thickness shall be 0.20 mm (60.008 in.) except for materials which have greater standard
commercial tolerances.
5.4 The test specimen for rods shall be 25.4-mm (1-in.) long for rods 25.4 mm in diameter or under and 12.7-mm ( ⁄2-in.) long
for larger-diameter rods. The diameter of the specimen shall be the diameter of the finished rod.
5.5 The test specimen for tubes less than 76 mm (3 in.) in inside diameter shall be the full section of the tube and 25.4-mm
(1-in.) long. For tubes 76 mm (3 in.) or more in inside diameter, a rectangular specimen shall be cut 76 mm in length in the
circumferential direction of the tube and 25.4 mm in width lengthwise of the tube.
5.6 The test specimens for sheets, rods, and tubes shall be machined, sawed, or sheared from the sample so as to have smooth
edges free from cracks. The cut edges shall be made smooth by finishing with No. 0 or finer sandpaper or emery cloth. Sawing,
machining, and sandpapering operations shall be slow enough so that the material is not heated appreciably.
NOTE 1—If there is any oil on the surface of the specimen when received or as a result of machining operations, wash the specimen with a cloth wet
with gasoline to remove oil, wipe with a dry cloth, and allow to stand in air for 2 h to permit evaporation of the gasoline. If gasoline attacks the plastic,
use some suitable solvent or detergent that will evaporate within the 2-h period.
5.7 The dimensions listed in the following table for the various specimens shall be measured to the nearest 0.025 mm (0.001
in.). Dimensions not listed shall be measured within 0.8 mm (6 ⁄32 in.).
Type of Dimensions to Be Measured to
Specimen the
Nearest 0.025 mm (0.001 in.)
Molded disk thickness
Sheet thickness
Rod length and diameter
Tube inside and outside diameter, and
wall thickness
6. Conditioning
6.1 Three specimens shall be conditioned as follows:
6.1.1 Specimens of materials whose water-absorption value would be appreciably affected by temperatures in the neighborhood
of 110°C (230°F), shall be dried in an oven for 24 h at 50 6 3°C (122 6 5.4°F), cooled in a desiccator, and immediately weighed
to the nearest 0.001 g.
NOTE 2—If a static charge interferes with the weighing, light
...
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