ASTM D5229 D5229M-1992(2004) Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials.pdf

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1、Designation: D 5229/D 5229M 92 (Reapproved 2004)Standard Test Method forMoisture Absorption Properties and EquilibriumConditioning of Polymer Matrix Composite Materials1This standard is issued under the fixed designation D 5229/D 5229M; the number immediately following the designation indicates they

2、ear of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Depa

3、rtment of Defense.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 D 570 and Practi

4、ces D 618 do notguarantee 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 properties

5、necessary for the analysis of single-phase Fickian moisture diffusion within such materials.1. Scope1.1 This test method covers a procedure (Procedure A) forthe determination of moisture absorption or desorption prop-erties in the through-the-thickness direction for single-phaseFickian solid materia

6、ls in flat or curved panel form. Alsocovered are procedures for conditioning test coupons prior touse in other test methods; either to equilibrium in a non-laboratory environment (Procedure B), to equilibrium in astandard laboratory atmosphere environment (Procedure C), orto an essentially moisture-

7、free state (Procedure D). Whileintended primarily for laminated polymer matrix compositematerials, these procedures are also applicable to other mate-rials that satisfy the assumptions of 1.2.1.2 The calculation of the through-the-thickness moisturediffusivity constant in Procedure A assumes a singl

8、e-phaseFickian material with constant moisture absorption propertiesthrough the thickness of the specimen. The validity of theequations used in Procedure A for evaluating the moisturediffusivity constant in a material of previously unknownmoisture absorption behavior is uncertain prior to the test,

9、asthe test results themselves determine if the material follows thesingle-phase Fickian diffusion model. A reinforced polymermatrix composite material tested below its glass-transitiontemperature typically meets this requirement, although two-phase matrices such as toughened epoxies may require amul

10、ti-phase moisture absorption model. While the test proce-dures themselves may be used for multi-phase materials, thecalculations used to determine the moisture diffusivity constantin Procedure A are applicable only to single-phase materials.Other examples of materials and test conditions that may no

11、tmeet the requirements are discussed in Section 1.4.1.3 The evaluation by Procedure A of the moisture equilib-rium content material property 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

12、resulting data reduced, by suitable auto-matic equipment.1.5 This test method is consistent with the recommendationsof MIL-HDBK-17B (1),2which describes the desirable at-tributes of a conditioning and moisture property determinationprocedure.1.6 The values stated in either SI units or inch-pound uni

13、tsare to be regarded separately as standard. Within the text theinch-pound units are shown in brackets. The values stated ineach system are not exact equivalents; therefore, each systemmust be used independently of the other. Combining valuesfrom the two systems may result in nonconformance with the

14、standard.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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1This

15、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 edition approved Mar. 1, 2004. Published March 2004. Originallyapproved in 1992. Last previous edition approved in 1998

16、 as D 5229/D 5229M 92(1998)e1.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2. Referenced Documents2.1 ASTM Standards:3D 570 Test Metho

17、d for Water Absorption of PlasticsD 618 Practice for Conditioning Plastics for TestingD 792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD 883 Terminology Relating to PlasticsD 2584 Test Method for Ignition Loss of Cured ReinforcedResinsD 2734 Test Met

18、hods for Void Content of Reinforced Plas-ticsD 3171 Test Method for Constituent Content of CompositeMaterialsD 3878 Terminology for Composite Materials2.2 Military Standard:MIL-B-131 Barrier Materials, Watervaporproof,Greaseproof, Flexible, Heat-Sealable43. Terminology3.1 DefinitionsTerminology D 38

19、78 defines terms relat-ing to high-modulus fibers and their composites. TerminologyD 883 defines terms relating to plastics. In the event of aconflict between terms, Terminology D 3878 shall have prece-dence over the other terminology standards.3.2 Definitions of Terms Specific to This StandardIf th

20、eterm represents a physical quantity, its analytical dimensionsare stated immediately following the term (or letter symbol) infundamental dimension form, using the following ASTMstandard symbology for fundamental dimensions, shownwithin square brackets: M for mass, L for length, T fortime, Q for the

21、rmodynamic temperature, and nd for non-dimensional quantities. Use of these symbols is restricted toanalytical dimensions when used within square brackets, as thesymbols may have other definitions when used without thebrackets.3.2.1 accuracy criterion, nthe maximum amount ofchange in average moistur

22、e content for a test coupon, over thespan of the reference time period, which is allowable for theestablishment of effective moisture equilibrium. (See alsoaverage moisture content, moisture equilibrium, and referencetime period.)3.2.2 average moisture content, M (%), nthe averageamount of absorbed

23、moisture in a material, taken as the ratio ofthe mass of the moisture in the material to the mass of theoven-dry material and expressed as a percentage, as follows:M,%5Wi2WoWo3100 (1)where:Wi= current specimen mass, g, andWo= oven-dry specimen mass, g.(See also oven-dry.)3.2.3 Fickian diffusion, na

24、model of material moistureabsorption and desorption that follows Ficks second law, asfollows in one-dimension:ct5Dz2cz23.2.4 glass transition temperature, TgQ, nthe approxi-mate midpoint of the temperature range over which a reversiblechange takes place between a viscous or rubbery condition anda ha

25、rd, relatively brittle condition, in an amorphous polymer, orin amorphous regions of a partially crystalline polymer.3.2.4.1 DiscussionThe glass transition temperature ofmany polymer matrix composites is lowered by the presence ofabsorbed moisture.3.2.5 moisture, nliquid (water, jet fuel, salt water

26、, or anyother liquid) that is either diffused in relatively small quantityand dispersed through a gas as a vapor, condensed on a surfaceas visible dew, or present in quantity sufficient for immersionof an object.3.2.5.1 DiscussionThe dictionary definition of moisturefor this test method is extended

27、to include not only the vaporof a liquid and its condensate, but the liquid itself in largequantities, as for immersion.3.2.6 moisture concentration, c ML3, nthe absoluteamount of absorbed moisture in a material expressed as themass of moisture per unit volume.3.2.7 moisture diffusivity constant, Dz

28、L2T1, nthe prop-erty of a material that describes the rate at which the materialabsorbs or desorbs moisture.3.2.7.1 DiscussionIn Fickian materials this property isrelatively independent of the moisture exposure level (and thusthe moisture equilibrium content material property). However,the moisture

29、diffusivity constant is strongly influenced bytemperature. Moisture diffusivity can be anisotropic; the sub-script z indicates the value in the through-the-thickness direc-tion for anisotropic diffusion behavior.3.2.8 moisture equilibrium, nthe condition reached by amaterial when there is essentiall

30、y no further change in itsaverage moisture content with the surrounding environment.Moisture equilibrium can be either absolute or effective.Absolute moisture equilibrium requires no measurable changein moisture content, while effective moisture equilibriumallows a specified small change in the aver

31、age moisture contentof a material (the accuracy criterion) over a specified time span(the reference time period). (See also accuracy criterion,average moisture content, and reference time period.)3.2.8.1 DiscussionEffective moisture equilibrium is a sat-isfactory definition for most engineering appl

32、ications. Unlessotherwise specified, references to moisture equilibrium in thistest method mean effective moisture equilibrium, as quantifiedin 10.2. Moisture equilibrium can also be either static, whenthere is no moisture transport at all across the surfaces, ordynamic, when moisture transport exis

33、ts, but the net sum forthe material is zero. This test method is not capable ofdiscerning between these two types of moisture equilibrium.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume

34、information, refer to the standards Document Summary page onthe ASTM website.4Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.D 5229/D 5229M 92 (2004)23.2.9 moisture equilibrium content, Mm(%), nthe maxi-mum amount of

35、absorbed moisture that a material can containat moisture equilibrium for a given moisture exposure level,expressed as a percent of dry material mass. (See also moisturesaturation content.)3.2.9.1 DiscussionIn polymer matrix composites, thisproperty is relatively independent of temperature (and thus

36、themoisture diffusivity constant material property), but it is afunction of the moisture exposure level. For the purposes ofthis test method Mmis assumed to be equivalent to the averagemoisture content at effective moisture equilibrium, Mf.3.2.10 moisture exposure level, na measure or descriptionof

37、the severity of a conditioning environment in terms of theamount of liquid or vapor present. (See also moisture andrelative vapor level.)3.2.11 moisture saturation content, nthe moisture equilib-rium content at the maximum possible moisture exposure level,wherein the material contains the greatest p

38、ossible amount ofabsorbed moisture. (See also moisture equilibrium content.)3.2.12 oven-dry, nthe condition of a material that hasbeen dried in accordance with Procedure D of this test methoduntil moisture equilibrium is achieved.3.2.13 reference time period, nthe time interval for massmeasurement u

39、sed to define effective moisture equilibrium in amaterial. (See also accuracy criterion, average moisture con-tent, and moisture equilibrium.)3.2.13.1 DiscussionA small change in the average mois-ture content (the accuracy criterion) for a material during thereference time period indicates effective

40、 moisture equilibrium.3.2.14 relative vapor level (%), nthe ratio of the pressureof a vapor present 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

41、. (See also moisture exposurelevel.)3.2.15 standard laboratory atmosphere, nan atmosphere(environment) having a temperature of 23 6 2C73.4 6 3.6F and a relative humidity of 50 6 10 %.3.2.16 standard conditioned specimen, nthe material con-dition of a test coupon that has reached effective moistureeq

42、uilibrium at a nominal relative humidity of 50 % in accor-dance with Procedure C of this test method.3.2.17 test temperature, nthe environmental temperatureused in Procedures A, B, C, or D.3.2.17.1 DiscussionThis is distinguished, for the purposesof this test method, from the environmental temperatu

43、re usedduring any subsequent material evaluation testing.3.2.18 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 tabbedmechani

44、cal coupon, or a coupon that does not meet theminimum 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 f

45、unctionfor materials that follow Fickian diffusion.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 conditio

46、ns: Mb, the average moisture content at abaseline time; Mf, the average moisture content at establish-ment of effective moisture equilibrium; Mi, the average mois-ture content at a given time; Mi 1, the average moisturecontent at the previous time; and Mm, the moisture equilibriumcontent that is rea

47、ched when a uniform through-the-thicknessmoisture profile occurs for a given temperature and moistureexposure level.3.3.5.1 DiscussionFor the purposes of this test methodMmand Mfare assumed to be equivalent.3.3.6 ttime.3.3.7 tmthe maximum time required for a material toreach moisture equilibrium und

48、er specified conditions of tem-perature and initial moisture content.3.3.8 Tgglass transition temperature.3.3.9 wthe width of a nominally square moisture absorp-tion test coupon.3.3.10 Wthe mass of a test coupon. The following sub-scripts are used to denote the mass of a test coupon for specificcond

49、itions: Wb, the mass at the baseline time; Wi, the mass ata given time; and Wi1, the mass at the previous time.3.3.11 zthe coordinate axis in the through-the-thicknessdirection for a plate or panel.4. Summary of Test Method4.1 This is a gravimetric test method that monitors thechange over time to the average moisture content of a materialspecimen by measuring the total mass change of a coupon thatis exposed on two sides to a specified environment. There arefour test procedures described by this test method. Procedure