1、Designation: C 613/C 613M 97 (Reapproved 2003)e1Standard 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 c
2、ase 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.e1NOTEWarning/preca
3、ution notes were moved into the text editorially in October 2003.1. Scope1.1 This test 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
4、 means of TestMethod D 3530/D 3530M.1.1.1 The reinforcement and filler must be substantiallyinsoluble 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
5、totalreinforcement content and total filler content; hybrid materialsystems with more 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, oth
6、er, unspecified, reagents may beused with this test method to extract other matrix material 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(mat
7、rix dissolution). Test Method D 2584 is preferred forreinforcement materials, such as 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,
8、 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. Specific precau-tionary statements are given in Section 9 and 7.2.3 and 8.2.1.2. Refer
9、enced Documents2.1 ASTM Standards:2D 883 Terminology Relating to PlasticsD 2584 Test Method for Ignition Loss of Cured ReinforcedResinsD 3171 Test Method for Constituent Content of CompositeMaterialsD 3529/D 3529M Test Method for Matrix Solids Contentand Matrix Content of Composite PrepregD 3530/D 3
10、530M Test Method for Volatiles Content ofComposite Material PrepregD 3878 Terminology of Composite MaterialsE 122 Practice for Calculating Sample Size to Estimate,With Specified Tolerable Error, the Average for Character-istic of a Lot or ProcessE 177 Practice for Use of Terms Precision and Bias inA
11、STM Test MethodsE 456 Terminology Relating to Quality and StatisticsE 1309 Guide for Identification of Composite Materials inComputerized Material Property DatabasesE 1471 Guide for Identification of Fiber-ReinforcedPolymer-Matrix Composite Materials in Databases2.2 NFPA Standard:NFPA 86 Standard fo
12、r Ovens and Furnaces33. Terminology3.1 DefinitionsTerminology D 3878 defines 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
13、 shall have precedenceover the other documents.1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.03 onConstituent/Precursor Properties.Current edition approved Oct. 1, 2003. Published October 2003. Originallya
14、pproved in 1967. Last previous edition approved in 1997 as C 613 97.2For 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 w
15、ebsite.3Available from National Fire Protection Association (NFPA), 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 prepre
16、g expressed either as percent by weight orpercent by volume. For 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 itha
17、s been partially cured to a controlled viscosity called “Bstage”. 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
18、test unit.43.1.5.1 DiscussionA test result may be a single observa-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 t
19、est unit, na unit or portion of a material that issufficient to 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
20、fromthese primary sampling units.3.2 Definitions of Terms Specific 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 co
21、mposite expressed either as percent by weight orpercent by volume.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, t
22、hen the fillercontent is included in the matrix content.3.2.3 reinforcement 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 replicat
23、e, na test specimen tested under nominallyidentical conditions 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
24、 of the resin mass.3.3 Symbols:3.3.1 Ainitial mass of dry reinforcement 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 sampl
25、epopulation for a given property.3.3.5 Maadditional mass of filler 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 sn1sta
26、ndard deviation statistic of a sample popu-lation for a given property.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 gi
27、ven property.3.3.15 xaverage value of a sample population for a 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
28、of Soxhlet extraction. The extracted residueis dried and weighed. 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
29、, the matrix content, reinforcement content, and fillercontent 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 ex
30、traction thimble, which is placed into theextraction chamber of 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
31、 of the extraction chamber, filling it until theliquid reaches 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.
32、 The heated reservoir boils the reagent, the vapor of4See Form and Style for ASTM Standards. FIG. 1 Schematic of Soxhlet Extraction ApparatusC 613/C 613M 97 (2003)e12which is led to a condenser placed above the extractionchamber. The distilled condensate then drips down into thethimble, starting onc
33、e again the process of filling the extractionchamber. The Soxhlet 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 theextract
34、ion flask from the condenser at 3 to 10 reflux changesper hour, with 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
35、 D 3530/D 3530M. Volatiles contentdetermination requires different 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 pr
36、epreg volatiles content, matrix content, reinforce-ment content, 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
37、of products made with such materials.5.2 The extraction products 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 thermose
38、tting matrix materials isdirectly related to the extent of cure of 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
39、2584 may be better test method choices.6.2 Reagent SelectionThe proper 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
40、 well on all material systems within thescope of this test method.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
41、assume that the reinforce-ment mass (or filler, if filler content 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 desc
42、ribed in 14.4.5. The resultingcorrection may be used if this change 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 s
43、elected.7. Apparatus7.1 General Requirements:7.1.1 Container VolumeA 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.
44、1.2 Thermal ShockLaboratory equipment that is sub-jected to non-ambient 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 spec
45、imen shall be constructed ofPTFE and test specimen cutting shall 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 ext
46、raction thimbles shall be capable of maintaining atemperature of 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 care tolimit volatile concentration in the oven by controlling samp
47、lequantity, temperature, and ventilation.)7.2.4 DesiccatorThe desiccator 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,
48、or fat-extracted cellulose paper, suitablefor use in the extraction 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
49、FlaskThe reservoir flask shall be ofborosilicate glass, of suitable volume (125 mL is 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
