1、Designation: D5229/D5229M 14Standard Test Method forMoisture Absorption Properties and EquilibriumConditioning of Polymer Matrix Composite Materials1This standard is issued under the fixed designation D5229/D5229M; the number immediately following the designation indicates theyear of original adopti
2、on or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. 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.
3、INTRODUCTIONConsistent evaluation and comparison of the response of polymer matrix composites to moistureabsorption can only be performed when the material has been brought to a uniform through-the-thickness moisture profile. The procedures described in Test Method D570 and Practices D618 do notguar
4、antee moisture equilibrium of the material. A similar, but more rigorous, procedure forconditioning to equilibrium is described by this test method, which can also be used with fluidmoisture other than water, and which, additionally, can provide the moisture absorption propertiesnecessary for the an
5、alysis of single-phase Fickian moisture diffusion within such materials.1. Scope1.1 This test method covers a procedure for the determina-tion of moisture absorption or desorption properties in thethrough-the-thickness direction for single-phase Fickian solidmaterials in flat or curved panel form. A
6、lso covered areprocedures for conditioning test coupons prior to use in othertest methods; either to an essentially moisture-free state, toequilibrium in a standard laboratory atmosphere environment,or to equilibrium in a non-laboratory environment. Alsoincluded are procedures for determining the mo
7、isture lossduring elevated temperature testing, as well as moisture lossresulting from thermal exposure after removal from the con-ditioning environment, such as during strain gage bonding.While intended primarily for laminated polymer matrix com-posite materials, these procedures are also applicabl
8、e to othermaterials that satisfy the assumptions of 1.2.1.2 The calculation of the through-the-thickness moisturediffusivity constant in Procedure A assumes a single-phaseFickian material with constant moisture absorption propertiesthrough the thickness of the specimen. The validity of theequations
9、used in Procedure A for evaluating the moisturediffusivity constant in a material of previously unknownmoisture absorption behavior is uncertain prior to the test, asthe test results themselves determine if the material follows thesingle-phase Fickian diffusion model. A reinforced polymermatrix comp
10、osite material tested below its glass-transitiontemperature typically meets this requirement, although two-phase matrices such as toughened epoxies may require amulti-phase moisture absorption model. While the test proce-dures themselves may be used for multi-phase materials, thecalculations used to
11、 determine the moisture diffusivity constantin Procedure A are applicable only to single-phase materials.Other examples of materials and test conditions that may notmeet the requirements are discussed in Section 6.1.3 The evaluation by Procedure A of the moisture equilib-rium content material proper
12、ty does not assume, and istherefore not limited to, single-phase Fickian diffusion behav-ior.1.4 The procedures used by this test method may beperformed, and the resulting data reduced, by suitable auto-matic equipment.1.5 This test method is consistent with the recommendationsof CMH-17 Rev G (1),2w
13、hich describes the desirable attri-butes of a conditioning and moisture property determinationprocedure.1.6 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system are not exact equivalents; therefore, each systemmust be used
14、 independently of the other. Combining valuesfrom the two systems may result in nonconformance with thestandard.1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.04 onLamina and Laminate Test Methods.Current e
15、dition approved May 15, 2014. Published May 2014. Originallyapproved in 1992. Last previous edition approved in 2012 as D5229/D5229M 12.DOI: 10.1520/D5229_D5229M-14.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.Copyright ASTM International, 100 Barr
16、Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.6.1 Within the text the inch-pound units are shown inbrackets.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to
17、 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D570 Test Method for Water Absorption of PlasticsD618 Practice for Conditioning Plastics for TestingD792 Test Methods for Density and
18、 Specific Gravity (Rela-tive Density) of Plastics by DisplacementD883 Terminology Relating to PlasticsD2584 Test Method for Ignition Loss of Cured ReinforcedResinsD2734 Test Methods for Void Content of Reinforced PlasticsD3171 Test Methods for Constituent Content of CompositeMaterialsD3878 Terminolo
19、gy for Composite Materials2.2 Military Standard:MIL-B-131 Barrier Materials, Watervaporproof,Greaseproof, Flexible, Heat-Sealable43. Terminology3.1 Definitions:3.1.1 Terminology D3878 defines terms relating to high-modulus fibers and their composites. Terminology D883 de-fines terms relating to plas
20、tics. In the event of a conflictbetween terms, Terminology D3878 shall have precedenceover the other terminology standards.3.2 Definitions of Terms Specific to This Standard:3.2.1 If the term represents a physical quantity, its analyticaldimensions are stated immediately following the term (or lette
21、rsymbol) in fundamental dimension form, using the followingASTM standard symbology for fundamental dimensions,shown within square brackets: M for mass, L for length, Tfor time, for thermodynamic temperature, and nd fornon-dimensional quantities. Use of these symbols is restrictedto analytical dimens
22、ions when used within square brackets, asthe symbols may have other definitions when used without thebrackets.3.2.2 accuracy criterion, nthe maximum amount ofchange in average moisture content for a test coupon, over thespan of the reference time period, which is allowable for theestablishment of ef
23、fective moisture equilibrium. (See alsoaverage moisture content, moisture equilibrium, and referencetime period.)3.2.3 average moisture content, M (%), nthe averageamount of absorbed moisture in a material, taken as the ratio ofthe mass of the moisture in the material to the mass of theoven-dry mate
24、rial and expressed as a percentage, as follows:M,%5Wi2 WoWo3100 (1)where:Wi= current specimen mass, g, andWo= oven-dry specimen mass, g.(See also oven-dry.)3.2.4 Fickian diffusion, na model of material moistureabsorption and desorption that follows Ficks second law, asfollows in one-dimension:ct5 Dz
25、2cz23.2.5 glass transition temperature, Tg,nthe approxi-mate midpoint of the temperature range over which a reversiblechange takes place between a viscous or rubbery condition anda hard, relatively brittle condition, in an amorphous polymer, orin amorphous regions of a partially crystalline polymer.
26、3.2.5.1 DiscussionThe glass transition temperature ofmany polymer matrix composites is lowered by the presence ofabsorbed moisture.3.2.6 moisture, nliquid (water, jet fuel, salt water, or anyother liquid) that is either diffused in relatively small quantityand dispersed through a gas as a vapor, con
27、densed on a surfaceas visible dew, or present in quantity sufficient for immersionof an object.3.2.6.1 DiscussionThe dictionary definition of moisturefor this test method is extended to include not only the vaporof a liquid and its condensate, but the liquid itself in largequantities, as for immersi
28、on.3.2.7 moisture concentration, c ML3, nthe absoluteamount of absorbed moisture in a material expressed as themass of moisture per unit volume.3.2.8 moisture diffusivity constant, DzL2T1, nthe prop-erty of a material that describes the rate at which the materialabsorbs or desorbs moisture.3.2.8.1 D
29、iscussionIn Fickian materials this property isrelatively independent of the moisture exposure level (and thusthe moisture equilibrium content material property). However,the moisture diffusivity constant is strongly influenced bytemperature. Moisture diffusivity can be anisotropic; the sub-script z
30、indicates the value in the through-the-thickness direc-tion for anisotropic diffusion behavior.3.2.9 moisture equilibrium, nthe condition reached by amaterial when there is essentially no further change in itsaverage moisture content with the surrounding environment.Moisture equilibrium can be eithe
31、r absolute or effective.Absolute moisture equilibrium requires no measurable changein moisture content, while effective moisture equilibriumallows a specified small change in the average moisture contentof a material (the accuracy criterion) over a specified time span(the reference time period). (Se
32、e also accuracy criterion,average moisture content, and reference time period.)3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page o
33、nthe ASTM website.4Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.D5229/D5229M 1423.2.9.1 DiscussionEffective moisture equilibrium is a sat-isfactory definition for most engineering applications
34、. Unlessotherwise specified, references to moisture equilibrium in thistest method mean effective moisture equilibrium, as quantifiedin section 10.2. Moisture equilibrium can also be either static,when there is no moisture transport at all across the surfaces, ordynamic, when moisture transport exis
35、ts, but the net sum forthe material is zero. This test method is not capable ofdiscerning between these two types of moisture equilibrium.3.2.10 moisture equilibrium content, Mm(%), nthe maxi-mum amount of absorbed moisture that a material can containat moisture equilibrium for a given moisture expo
36、sure level,expressed as a percent of dry material mass. (See also moisturesaturation content.)3.2.10.1 DiscussionIn polymer matrix composites, thisproperty is relatively independent of temperature (and thus themoisture diffusivity constant material property), but it is afunction of the moisture expo
37、sure level. For the purposes ofthis test method Mmis assumed to be equivalent to the averagemoisture content at effective moisture equilibrium, Mf.3.2.11 moisture exposure level, na measure or descriptionof the severity of a conditioning environment in terms of theamount of liquid or vapor present.
38、(See also moisture andrelative vapor level.)3.2.12 moisture saturation content, nthe moisture equilib-rium content at the maximum possible moisture exposure level,wherein the material contains the greatest possible amount ofabsorbed moisture. (See also moisture equilibrium content.)3.2.13 oven-dry,
39、nthe condition of a material that has beendried in accordance with Procedure D of this test method untilmoisture equilibrium is achieved.3.2.14 reference time period, nthe time interval for massmeasurement used to define effective moisture equilibrium in amaterial. (See also accuracy criterion, aver
40、age moisturecontent, and moisture equilibrium. )3.2.14.1 DiscussionA small change in the average mois-ture content (the accuracy criterion) for a material during thereference time period indicates effective moisture equilibrium.3.2.15 relative vapor level (%), nthe ratio of the pressureof a vapor pr
41、esent to the pressure of the saturated vapor, at thesame temperature, expressed as a percent. Applicable only tothe gaseous form of a fluid. When the vapor is water vapor theterm is called relative humidity. (See also moisture exposurelevel.)3.2.16 standard laboratory atmosphere, nan atmosphere(envi
42、ronment) having a temperature of 23 6 2C73.4 6 3.6F and a relative humidity of 50 6 10 %.3.2.17 standard conditioned specimen, nthe material con-dition of a test coupon that has reached effective moistureequilibrium at a nominal relative humidity of 50 % (consideredto be a standard laboratory enviro
43、nment) in accordance withProcedure C of this test method.3.2.18 test temperature, nthe environmental temperatureused in Procedures A-E, Y, Z.3.2.18.1 DiscussionThis is distinguished, for the purposesof this test method, from the environmental temperature usedduring any subsequent material evaluation
44、 testing.3.2.19 traveler coupon, na surrogate coupon of the samematerial and thickness, and of appropriate size (but withouttabs) that is used in a conditioning procedure to determinemoisture content for specimen configurations (such as a tabbedmechanical coupon, or a coupon that does not meet themi
45、nimum mass requirement) that cannot otherwise be properlymeasured by this test method.3.3 Symbols:3.3.1 cmoisture concentration.3.3.2 Dzmoisture diffusivity constant in the through-the-thickness direction.3.3.3 G(T,t)moisture absorption or desorption function formaterials that follow Fickian diffusi
46、on.3.3.4 hthickness of a material panel or plate in thethrough-the-thickness direction for double-sided moisture ex-posure.3.3.5 Maverage moisture content of a material. The fol-lowing subscripts denote the average moisture content forspecific conditions:Mb, the average moisture content at a baselin
47、e time;Me, the average moisture content at establishment of effec-tive moisture equilibrium;Med, the average moisture content at establishment ofeffective moisture equilibrium as a delta from the averagemoisture content at a baseline time;Met, the average moisture content at establishment of effec-t
48、ive moisture equilibrium as a total value from the condition ofzero moisture content;Mf, the final moisture content at the end of conditioning fora fixed time;Mi, the average moisture content at a given time;Mi 1, the average moisture content at the previous time;ML, the moisture loss from the state
49、 of effective equilibriumdue to subsequent heating; andMm, the moisture equilibrium content that is reached when auniform through-the-thickness moisture profile occurs for agiven temperature and moisture exposure level.3.3.5.1 DiscussionProcedures A-H of this test methodcondition specimens to Me. Except for the use of a thinspecimen in Procedure A, conditioning specimens to Mmisgenerally not practical. See also the discussion in AppendixX2.3.3.6 ttime.3.3.7 tmthe maximum time required for a material to reachmoisture eq
