1、Designation: C 613/C 613M 97 (Reapproved 2008)Standard Test Method forConstituent Content of Composite Prepreg by SoxhletExtraction1This standard is issued under the fixed designation C 613/C 613M; the number immediately following the designation indicates the yearof original adoption or, in the cas
2、e 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test
3、 method covers a Soxhlet extraction procedureto determine the matrix content, reinforcement content, andfiller content of composite material prepreg. Volatiles content,if appropriate, and required, is determined by means of TestMethod D 3530/D 3530M.1.1.1 The reinforcement and filler must be substan
4、tiallyinsoluble in the selected extraction reagent and any filler mustbe capable of being separated from the reinforcement byfiltering the extraction residue.1.1.2 Reinforcement and filler content test results are totalreinforcement content and total filler content; hybrid materialsystems with more
5、than one type of either reinforcement orfiller cannot be distinguished.1.2 This test method focuses on thermosetting matrix ma-terial systems for which the matrix may be extracted by anorganic solvent. However, other, unspecified, reagents may beused with this test method to extract other matrix mat
6、erial typesfor the same purposes.1.3 Alternate techniques for determining matrix and rein-forcement content include Test Methods D 3171 (matrix diges-tion), D 2584 (matrix burn-off/ignition), and D 3529/D 3529M(matrix dissolution). Test Method D 2584 is preferred forreinforcement materials, such as
7、glass, quartz, or silica, that areunaffected by high-temperature environments.1.4 The values stated in SI units are to be regarded asstandard.1.5 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
8、 to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 9 and 7.2.3 and 8.2.1.2. Referenced Documents2.1 ASTM Standards:2D 883 Terminology Relating to PlasticsD 2584 Test M
9、ethod for Ignition Loss of Cured ReinforcedResinsD 3171 Test Methods for Constituent Content of CompositeMaterialsD 3529/D 3529M Test Method for Matrix Solids Contentand Matrix Content of Composite PrepregD 3530/D 3530M Test Method for Volatiles Content ofComposite Material PrepregD 3878 Terminology
10、 for Composite MaterialsE 122 Practice for Calculating Sample Size to Estimate,With Specified Precision, the Average for a Characteristicof a Lot or ProcessE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 456 Terminology Relating to Quality and StatisticsE 1309 Guide for I
11、dentification of Fiber-ReinforcedPolymer-Matrix Composite Materials in DatabasesE 1471 Guide for Identification of Fibers, Fillers, and CoreMaterials in Computerized Material Property Databases2.2 NFPA Standard:NFPA 86 Standard for Ovens and Furnaces33. Terminology3.1 DefinitionsTerminology D 3878 d
12、efines terms relatingto composite materials. Terminology D 883 defines termsrelating to plastics. Terminology E 456 and Practice E 177define terms relating to statistics. In the event of a conflictbetween terms, Terminology D 3878 shall have precedenceover the other documents.1This test method is un
13、der the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.03 onConstituent/Precursor Properties.Current edition approved March 1, 2008. Published April 2008. Originallyapproved in 1967. Last previous edition approved in 2003 as C 613 97(200
14、3)e1.2For 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 onthe ASTM website.3Available from National Fire Protection Association (NF
15、PA), 1 BatterymarchPark, Quincy, MA 02269-9101.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.1 matrix content, nthe amount of matrix present in acomposite or prepreg expressed either as percent by weight orpercent by volume. Fo
16、r polymer matrix composites this is resincontent. D 38783.1.2 prepreg, nthe admixture of fibrous reinforcementand polymeric matrix used to fabricate composite materials. Itsform may be sheet, tape, or tow. For thermosetting matrices ithas been partially cured to a controlled viscosity called “Bstage
17、”. D 38783.1.3 resin content, nsee matrix content. D 38783.1.4 sample, na small part or portion of a material orproduct intended to be representative of the whole. D 8833.1.5 test result, nthe value obtained for a given propertyfrom one test unit.43.1.5.1 DiscussionA test result may be a single obse
18、rva-tion or a combination of a number of observations when two ormore test specimens are measured for each test.3.1.6 test specimen, na test unit or portion of a test unitupon which a single or multiple observation is to be made.43.1.7 test unit, na unit or portion of a material that issufficient to
19、 obtain a test result(s) for the property or propertiesto be measured.3.1.7.1 DiscussionA test unit may be a subunit of aprimary (first stage) sampling unit or it may be a subunit of acomposite of primary sampling units or of increments fromthese primary sampling units.3.2 Definitions of Terms Speci
20、fic to This Standard:3.2.1 dry resin content, nprepreg resin content calculatedby subtracting the average mass loss due to volatiles from theinitial test specimen mass.3.2.2 filler content, nthe amount of filler present in aprepreg or composite expressed either as percent by weight orpercent by volu
21、me.3.2.2.1 DiscussionIn this test method the reinforcement isseparated from the remainder of the material, which includesthe matrix and the filler. If the filler is not then separated fromthe matrix to determine the proportion of each, then the fillercontent is included in the matrix content.3.2.3 r
22、einforcement content, nthe amount of reinforce-ment present in a composite or prepreg expressed either aspercent by weight or percent by volume. This is sometimesstated as a fraction, that is, reinforcement volume fraction.3.2.4 replicate, na test specimen tested under nominallyidentical conditions
23、as other test specimens from the samesample.3.2.5 volatiles content, nthe amount of volatiles present ina prepreg expressed as percent by weight.3.2.6 wet resin content, nprepreg resin content deter-mined by considering volatiles as part of the resin mass.3.3 Symbols:3.3.1 Ainitial mass of dry reinf
24、orcement during a reagentexposure evaluation.3.3.2 Bfinal mass of dry reinforcement during a reagentexposure evaluation.3.3.3 cpercent reinforcement mass change due to reagentexposure.3.3.4 CVcoefficient of variation statistic of a samplepopulation for a given property.3.3.5 Maadditional mass of fil
25、ler in the test specimen.3.3.6 Memass of the test specimen extraction residue.3.3.7 Miinitial mass of the test specimen.3.3.8 Mrmass of reinforcement in the test specimen.3.3.9 nnumber of replicates in the sample population.3.3.10 sn1standard deviation statistic of a sample popu-lation for a given p
26、roperty.3.3.11 Wfweight percent of filler in prepreg.3.3.12 Wmweight percent of matrix in prepreg.3.3.13 Wrweight percent of reinforcement in prepreg.3.3.14 xitest result for an individual test specimen fromthe sample population for a given property.3.3.15 xaverage value of a sample population for a
27、 givenproperty.4. Summary of Test Method4.1 The exposed surface area of the prepreg material testspecimen is increased by cutting the test specimen into smallerpieces. The test specimen is weighed and the matrix materialremoved by means of Soxhlet extraction. The extracted residueis dried and weighe
28、d. If a filler is present in the residue, inaddition to reinforcement, the two components are separatedby filtering the residue. From mass measurements of the initialtest specimen, and of the residue taken at various stages in theprocess, the matrix content, reinforcement content, and fillercontent
29、are calculated and reported in weight percent.4.1.1 Soxhlet ProcessWhile described in detail in com-mon quantitative chemical analysis textbooks, the Soxhletprocess is summarized as follows. The test specimen is loadedinto a filtering extraction thimble, which is placed into theextraction chamber of
30、 a Soxhlet extraction assembly (see Fig.1) containing an appropriate extraction reagent. The porousthimble allows the liquid extraction reagent to pass whileretaining the test specimen. Freshly distilled liquid reagententers from the top of the extraction chamber, filling it until theliquid reaches
31、the highest level of the reagent-return tube. Atthis moment the tube operates as a siphon, draining theextraction chamber completely as it returns the liquid reagentand any extracted material to a reservoir beneath the extractionchamber. The heated reservoir boils the reagent, the vapor of4See Form
32、and Style for ASTM Standards. FIG. 1 Schematic of Soxhlet Extraction ApparatusC 613/C 613M 97 (2008)2which is led to a condenser placed above the extractionchamber. The distilled condensate then drips down into thethimble, starting once again the process of filling the extractionchamber. The Soxhlet
33、 operation is not a continuous operation,but rather a sequence of fillings and siphonings, each cycle ofwhich is called a reflux change. The heat input and reagentvolume are adjusted to cause the boiling reagent to return to theextraction flask from the condenser at 3 to 10 reflux changesper hour, w
34、ith the extraction continuing for a minimum of 4 hor 20 reflux changes, whichever comes first.4.1.2 Volatiles ContentVolatiles content is primarily ap-plicable to thermosetting materials, and, if required, is deter-mined by Test Method D 3530/D 3530M. Volatiles contentdetermination requires differen
35、t test specimens than those usedin the extraction process, since the process of determiningvolatiles content renders thermosetting material specimensunsuitable for subsequent organic solvent extraction.5. Significance and Use5.1 The prepreg volatiles content, matrix content, reinforce-ment content,
36、and filler content of composite prepreg materialsare used to control material manufacture and subsequentfabrication processes, and are key parameters in the specifica-tion and production of such materials, as well as in thefabrication of products made with such materials.5.2 The extraction products
37、resulting from this test method(the extract, the residue, or both) can be analyzed to assesschemical composition and degree of purity.6. Interferences6.1 Extent of Cure in Thermosetting SystemsThe effi-ciency of extraction for thermosetting matrix materials isdirectly related to the extent of cure o
38、f the resin system. Resinsthat have started to cross-link (such as B-staged resins) will beincreasingly more difficult to extract as the cure advances. Thistest method may not be appropriate for such materials; TestMethods D 3171 or D 2584 may be better test method choices.6.2 Reagent SelectionThe p
39、roper reagent, in a suitablequantity, must be selected for the constituents under test. Thereagents listed in Section 8 are provided for consideration,particularly with regard to thermosetting materials, but cannotbe assured to perform well on all material systems within thescope of this test method
40、.6.3 Thimble ContaminationIf the extract is to undergofurther analysis, the thimble must be clean to avoid a signifi-cant source of contamination.6.4 Reinforcement Mass Change As a Result of ReagentThe calculations of this test method assume that the reinforce-ment mass (or filler, if filler content
41、 is being determined) is notsignificantly affected (whether mass increase or mass loss) byexposure to the reagent. Small, consistent changes in thereinforcement mass caused by exposure to the reagent can becorrected by the process described in 14.4.5. The resultingcorrection may be used if this chan
42、ge is sufficiently reproduc-ible under the conditions of the test, and if this change has thesame value for the reinforcement alone as for the reinforcementin the matrix. Otherwise, a different reagent, or another testmethod, must be selected.7. Apparatus7.1 General Requirements:7.1.1 Container Volu
43、meA suggested volume is shown foreach container. However, other sizes may be required depend-ing upon the test specimen size, the amount of reagent neededto complete the extraction process, and the relative sizes ofrelated equipment.7.1.2 Thermal ShockLaboratory equipment that is sub-jected to non-a
44、mbient temperatures (hot or cold) shall be oftempered-glass or PTFE materials.7.1.3 Post-Test Elemental AnalysisIf a post-test elementalanalysis of the extract or residue is to be performed, laboratoryequipment contacting the test specimen shall be constructed ofPTFE and test specimen cutting shall
45、be limited to tools that donot leave an elemental trace.7.2 General Equipment:7.2.1 Analytical BalanceThe analytical balance shall becapable of reading to within 60.1 mg.7.2.2 Muffle FurnaceThe muffle furnace used to conditionglass extraction thimbles shall be capable of maintaining atemperature of
46、510 6 15C.7.2.3 Air-Circulating Drying OvenThe drying oven shallbe capable of maintaining a temperature of 163 6 3C.(WarningFor safety purposes listed in NFPA 86, take careto limit volatile concentration in the oven by controllingsample quantity, temperature, and ventilation.)7.2.4 DesiccatorThe des
47、iccator shall be capable of con-taining the required test specimens.7.3 Extraction Assembly:7.3.1 Extraction ThimblesThe extraction thimbles shallbe deep, narrow filtering cups, of either borosilicate glass in anappropriate pore size, or fat-extracted cellulose paper, suitablefor use in the extracti
48、on chamber.7.3.2 Hot PlateThe hot plate shall have adjustable con-trols suitable for heating the reagent within the reservoir flaskto 260C and shall be capable of controlling the requiredreagent temperature within 615C.7.3.3 Reservoir FlaskThe reservoir flask shall be ofborosilicate glass, of suitab
49、le volume (125 mLis suggested) forthe reagent quantity and extraction chamber volume, and shallhave a ground tapered joint capable of connection with theremainder of the assembly.7.3.4 Soxhlet Extraction ChamberThe extraction cham-ber shall be of borosilicate glass, with an automatic recyclingsiphon that recycles at a suitable liquid volume (50 mL issuggested), and with a ground tapered joint at each end capableof connecting with the remainder of the assembly.7.3.5 Condensing ChamberThe condensing chambershall be of borosilicat
