ASTM D5229/D5229M-92(2010)
(Test Method)Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials
Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials
SIGNIFICANCE AND USE
Procedure A is designed to produce moisture diffusion material property data that may be used as follows:
To determine approximate exposure times for coupon conditioning in Procedures B, C, or D;
As input to moisture prediction analysis computer codes; or
For making qualitative decisions on material selection or performance under environmental exposure to various forms of moisture.
Procedures B, C, and D are designed to condition test coupons to a specified moisture equilibrium state prior to other material property testing (including but not limited to mechanical testing).
A single test using Procedure A provides the moisture diffusivity constant, Dz, and the moisture equilibrium content, Mm, at the given moisture exposure level and temperature. Multiple tests at differing temperatures are required to establish the dependence of Dz on temperature. Multiple tests at differing moisture exposure levels are required to establish the dependence of Mm on moisture exposure level.
Vapor-exposure testing shall be used to condition the specimen when the in-service environmental condition is a vapor such as humid air. Immersion in a liquid bath should be used to simulate vapor exposure only when apparent absorption properties are desired for qualitative purposes. Properties determined in the latter manner shall be reported as apparent properties.
Note 1—For many polymer matrix composites the volume percent reinforcement can be determined by one of the matrix digestion procedures of Test Method D3171, or, for certain reinforcement materials such as glass and ceramics, by the matrix burn-off technique of Test Method D2584. Test Methods D2734 describes the limitations and use of the calculations required to approximate the void content in the composite. The void content equations of Test Methods D2734 are applicable to both Test Methods D2584 and D3171. Test Methods D792 can be used to determine specific gravity.
SCOPE
1.1 This test method covers a procedure (Procedure A) for the determination of moisture absorption or desorption properties in the through-the-thickness direction for single-phase Fickian solid materials in flat or curved panel form. Also covered are procedures for conditioning test coupons prior to use in other test methods; either to equilibrium in a non-laboratory environment (Procedure B), to equilibrium in a standard laboratory atmosphere environment (Procedure C), or to an essentially moisture-free state (Procedure D). While intended primarily for laminated polymer matrix composite materials, these procedures are also applicable to other materials that satisfy the assumptions of 1.2.
1.2 The calculation of the through-the-thickness moisture diffusivity constant in Procedure A assumes a single-phase Fickian material with constant moisture absorption properties through the thickness of the specimen. The validity of the equations used in Procedure A for evaluating the moisture diffusivity constant in a material of previously unknown moisture absorption behavior is uncertain prior to the test, as the test results themselves determine if the material follows the single-phase Fickian diffusion model. A reinforced polymer matrix composite material tested below its glass-transition temperature typically meets this requirement, although two-phase matrices such as toughened epoxies may require a multi-phase moisture absorption model. While the test procedures themselves may be used for multi-phase materials, the calculations used to determine the moisture diffusivity constant in Procedure A are applicable only to single-phase materials. Other examples of materials and test conditions that may not meet the requirements are discussed in Section 1.4.
1.3 The evaluation by Procedure A of the moisture equilibrium content material property does not assume, and is therefore not limited to, single-phase Fickian diffusion behavior.
1.4 The procedures used by this test met...
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Designation: D5229/D5229M – 92 (Reapproved 2010)
Standard Test Method for
Moisture Absorption Properties and Equilibrium
Conditioning of Polymer Matrix Composite Materials
This standard is issued under the fixed designation D5229/D5229M; 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 Department of Defense.
INTRODUCTION
Consistent evaluation and comparison of the response of polymer matrix composites to moisture
absorption can only be performed when the material has been brought to a uniform through-the-
thickness moisture profile.The procedures described inTest Method D570 and Practices D618 do not
guarantee moisture equilibrium of the material. A similar, but more rigorous, procedure for
conditioning to equilibrium is described by this test method, which can also be used with fluid
moisture other than water, and which, additionally, can provide the moisture absorption properties
necessary for the analysis of single-phase Fickian moisture diffusion within such materials.
1. Scope multi-phase moisture absorption model. While the test proce-
dures themselves may be used for multi-phase materials, the
1.1 This test method covers a procedure (Procedure A) for
calculationsusedtodeterminethemoisturediffusivityconstant
the determination of moisture absorption or desorption prop-
in Procedure A are applicable only to single-phase materials.
erties in the through-the-thickness direction for single-phase
Other examples of materials and test conditions that may not
Fickian solid materials in flat or curved panel form. Also
meet the requirements are discussed in Section 1.4.
covered are procedures for conditioning test coupons prior to
1.3 The evaluation by ProcedureAof the moisture equilib-
use in other test methods; either to equilibrium in a non-
rium content material property does not assume, and is
laboratory environment (Procedure B), to equilibrium in a
therefore not limited to, single-phase Fickian diffusion behav-
standard laboratory atmosphere environment (Procedure C), or
ior.
to an essentially moisture-free state (Procedure D). While
1.4 The procedures used by this test method may be
intended primarily for laminated polymer matrix composite
performed, and the resulting data reduced, by suitable auto-
materials, these procedures are also applicable to other mate-
matic equipment.
rials that satisfy the assumptions of 1.2.
1.5 Thistestmethodisconsistentwiththerecommendations
1.2 The calculation of the through-the-thickness moisture
of MIL-HDBK-17B (1), which describes the desirable attri-
diffusivity constant in Procedure A assumes a single-phase
butes of a conditioning and moisture property determination
Fickian material with constant moisture absorption properties
procedure.
through the thickness of the specimen. The validity of the
1.6 The values stated in either SI units or inch-pound units
equations used in Procedure A for evaluating the moisture
are to be regarded separately as standard. Within the text the
diffusivity constant in a material of previously unknown
inch-pound units are shown in brackets. The values stated in
moisture absorption behavior is uncertain prior to the test, as
each system are not exact equivalents; therefore, each system
thetestresultsthemselvesdetermineifthematerialfollowsthe
must be used independently of the other. Combining values
single-phase Fickian diffusion model. A reinforced polymer
from the two systems may result in nonconformance with the
matrix composite material tested below its glass-transition
standard.
temperature typically meets this requirement, although two-
1.7 This standard does not purport to address all of the
phase matrices such as toughened epoxies may require a
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
This test method is under the jurisdiction of ASTM Committee D30 on
bility of regulatory limitations prior to use.
Composite Materials and is the direct responsibility of Subcommittee D30.04 on
Lamina and Laminate Test Methods.
Current edition approved May 1, 2010. Published June 2010. Originally
approved in 1992. Last previous edition approved in 2004 as D5229/D5229M–92 Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
(2004). DOI: 10.1520/D5229_D5229M-92R10. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5229/D5229M – 92 (2010)
2. Referenced Documents (See also oven-dry.)
3.2.4 Fickian diffusion, n—a model of material moisture
2.1 ASTM Standards:
absorption and desorption that follows Fick’s second law, as
D570 Test Method for Water Absorption of Plastics
follows in one-dimension:
D618 Practice for Conditioning Plastics for Testing
D792 Test Methods for Density and Specific Gravity (Rela-
]c ] c
5D
tive Density) of Plastics by Displacement z 2
]t
]z
D883 Terminology Relating to Plastics
3.2.5 glass transition temperature, T [Q], n—the approxi-
g
D2584 Test Method for Ignition Loss of Cured Reinforced
matemidpointofthetemperaturerangeoverwhichareversible
Resins
changetakesplacebetweenaviscousorrubberyconditionand
D2734 Test Methods for Void Content of Reinforced Plas-
ahard,relativelybrittlecondition,inanamorphouspolymer,or
tics
in amorphous regions of a partially crystalline polymer.
D3171 Test Methods for Constituent Content of Composite
3.2.5.1 Discussion—The glass transition temperature of
Materials
manypolymermatrixcompositesisloweredbythepresenceof
D3878 Terminology for Composite Materials
absorbed moisture.
2.2 Military Standard:
MIL-B-131 Barrier Materials, Watervaporproof, 3.2.6 moisture, n—liquid (water, jet fuel, salt water, or any
other liquid) that is either diffused in relatively small quantity
Greaseproof, Flexible, Heat-Sealable
anddispersedthroughagasasavapor,condensedonasurface
3. Terminology
as visible dew, or present in quantity sufficient for immersion
3.1 Definitions: of an object.
3.1.1 Terminology D3878 defines terms relating to high-
3.2.6.1 Discussion—The dictionary definition of moisture
modulus fibers and their composites. Terminology D883 de- for this test method is extended to include not only the vapor
fines terms relating to plastics. In the event of a conflict
of a liquid and its condensate, but the liquid itself in large
between terms, Terminology D3878 shall have precedence quantities, as for immersion.
−3
over the other terminology standards.
3.2.7 moisture concentration, c [ML ], n—the absolute
3.2 Definitions of Terms Specific to This Standard:
amount of absorbed moisture in a material expressed as the
3.2.1 Ifthetermrepresentsaphysicalquantity,itsanalytical
mass of moisture per unit volume.
2 −1
dimensionsarestatedimmediatelyfollowingtheterm(orletter
3.2.8 moisture diffusivity constant, D [L T ], n—the prop-
z
symbol) in fundamental dimension form, using the following
erty of a material that describes the rate at which the material
ASTM standard symbology for fundamental dimensions,
absorbs or desorbs moisture.
shownwithinsquarebrackets:[M]formass,[L]forlength,[T]
3.2.8.1 Discussion—In Fickian materials this property is
for time, [Q] for thermodynamic temperature, and [nd] for
relativelyindependentofthemoistureexposurelevel(andthus
non-dimensional quantities. Use of these symbols is restricted
the moisture equilibrium content material property). However,
to analytical dimensions when used within square brackets, as
the moisture diffusivity constant is strongly influenced by
the symbols may have other definitions when used without the
temperature. Moisture diffusivity can be anisotropic; the sub-
brackets.
script z indicates the value in the through-the-thickness direc-
3.2.2 accuracy criterion, n—the maximum amount of
tion for anisotropic diffusion behavior.
change in average moisture content for a test coupon, over the
3.2.9 moisture equilibrium, n—the condition reached by a
span of the reference time period, which is allowable for the
material when there is essentially no further change in its
establishment of effective moisture equilibrium. (See also
average moisture content with the surrounding environment.
average moisture content, moisture equilibrium, and reference
Moisture equilibrium can be either absolute or effective.
time period.)
Absolute moisture equilibrium requires no measurable change
3.2.3 average moisture content, M (%), n—the average
in moisture content, while effective moisture equilibrium
amountofabsorbedmoistureinamaterial,takenastheratioof
allowsaspecifiedsmallchangeintheaveragemoisturecontent
the mass of the moisture in the material to the mass of the
ofamaterial(theaccuracycriterion)overaspecifiedtimespan
oven-dry material and expressed as a percentage, as follows:
(the reference time period). (See also accuracy criterion,
W 2W
i o average moisture content, and reference time period.)
M,%5 3100 (1)
W
o
3.2.9.1 Discussion—Effectivemoistureequilibriumisasat-
isfactory definition for most engineering applications. Unless
where:
otherwise specified, references to moisture equilibrium in this
W = current specimen mass, g, and
i
test method mean effective moisture equilibrium, as quantified
W = oven-dry specimen mass, g.
o
in 10.2. Moisture equilibrium can also be either static, when
there is no moisture transport at all across the surfaces, or
dynamic, when moisture transport exists, but the net sum for
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
the material is zero. This test method is not capable of
Standards volume information, refer to the standard’s Document Summary page on
discerning between these two types of moisture equilibrium.
the ASTM website.
3.2.10 moisture equilibrium content, M (%), n—the maxi-
AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700 m
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS. mum amount of absorbed moisture that a material can contain
D5229/D5229M – 92 (2010)
at moisture equilibrium for a given moisture exposure level, 3.3.3 G(T,t)—moisture absorption or desorption function
expressedasapercentofdrymaterialmass.(Seealsomoisture for materials that follow Fickian diffusion.
saturation content.) 3.3.4 h—thickness of a material panel or plate in the
through-the-thickness direction for double-sided moisture ex-
3.2.10.1 Discussion—In polymer matrix composites, this
posure.
property is relatively independent of temperature (and thus the
3.3.5 M—average moisture content of a material. The fol-
moisture diffusivity constant material property), but it is a
lowing subscripts denote the average moisture content for
function of the moisture exposure level. For the purposes of
specific conditions: M , the average moisture content at a
this test method M is assumed to be equivalent to the average
b
m
baseline time; M, the average moisture content at establish-
moisture content at effective moisture equilibrium, M. f
f
ment of effective moisture equilibrium; M, the average mois-
3.2.11 moisture exposure level, n—a measure or description i
ture content at a given time; M , the average moisture
i−1
of the severity of a conditioning environment in terms of the
content at the previous time; and M , the moisture equilibrium
amount of liquid or vapor present. (See also moisture and m
content that is reached when a uniform through-the-thickness
relative vapor level.)
moisture profile occurs for a given temperature and moisture
3.2.12 moisture saturation content, n—the moisture equi-
exposure level.
librium content at the maximum possible moisture exposure
3.3.5.1 Discussion—For the purposes of this test method
level, wherein the material contains the greatest possible
M and M are assumed to be equivalent.
m f
amount of absorbed moisture. (See also moisture equilibrium
3.3.6 t—time.
content.)
3.3.7 t —the maximum time required for a material to
m
3.2.13 oven-dry, n—the condition of a material that has
reach moisture equilibrium under specified conditions of tem-
been dried in accordance with Procedure D of this test method
perature and initial moisture content.
until moisture equilibrium is achieved.
3.3.8 T —glass transition temperature.
g
3.2.14 reference time period, n—the time interval for mass
3.3.9 w—the width of a nominally square moisture absorp-
measurementusedtodefineeffectivemoistureequilibriumina
tion test coupon.
material. (See also accuracy criterion, average moisture con-
3.3.10 W—the mass of a test coupon. The following sub-
tent, and moisture equilibrium.)
scriptsareusedtodenotethemassofatestcouponforspecific
3.2.14.1 Discussion—A small change in the average mois-
conditions: W , the mass at the baseline time; W, the mass at
b i
ture content (the accuracy criterion) for a material during the
a given time; and W , the mass at the previous time.
i−1
reference time period indicates effective moisture equilibrium.
3.3.11 z—the coordinate axis in the through-the-thickness
3.2.15 relative vapor level (%), n—the ratio of the pressure
direction for a plate or panel.
of a vapor present to the pressure of the saturated vapor, at the
4. Summary of Test Method
same temperature, expressed as a percent. Applicable only to
the gaseous form of a fluid.When the vapor is water vapor the 4.1 This is a gravimetric test method that monitors the
term is called relative humidity. (See also moisture exposure change over time to the average moisture content of a material
level.) specimen by measuring the total mass change of a coupon that
is exposed on two sides to a specified environment. There are
3.2.16 standard laboratory atmosphere, n—an atmosphere
fourtestproceduresdescribedbythistestmethod.ProcedureA
(environment) having a temperature of 23 6 2°C
covers the determination of the two Fickian moisture diffusion
[73.4 63.6°F] and a relative humidity of 50 610%.
material properties, the moisture diffusivity constant and the
3.2.17 standardconditionedspecimen,n—thematerialcon-
moistureequilibriumcontent.Theotherthreeprocedurescover
dition of a test coupon that has reached effective moisture
material conditioning to a specific moisture environment;
equilibrium at a nominal relative humidity of 50% in accor-
Procedure B covers general moisture conditioning of material
dance with Procedure C of this test method.
coupons prior to other types of testing; P
...
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