ASTM C613/C613M-97(2008)
(Test Method)Standard Test Method for Constituent Content of Composite Prepreg by Soxhlet Extraction
Standard Test Method for Constituent Content of Composite Prepreg by Soxhlet Extraction
SIGNIFICANCE AND USE
The prepreg volatiles content, matrix content, reinforcement content, and filler content of composite prepreg materials are used to control material manufacture and subsequent fabrication processes, and are key parameters in the specification and production of such materials, as well as in the fabrication of products made with such materials.
The extraction products resulting from this test method (the extract, the residue, or both) can be analyzed to assess chemical composition and degree of purity.
SCOPE
1.1 This test method covers a Soxhlet extraction procedure to determine the matrix content, reinforcement content, and filler content of composite material prepreg. Volatiles content, if appropriate, and required, is determined by means of Test Method D 3530/D 3530M.
1.1.1 The reinforcement and filler must be substantially insoluble in the selected extraction reagent and any filler must be capable of being separated from the reinforcement by filtering the extraction residue.
1.1.2 Reinforcement and filler content test results are total reinforcement content and total filler content; hybrid material systems with more than one type of either reinforcement or filler cannot be distinguished.
1.2 This test method focuses on thermosetting matrix material systems for which the matrix may be extracted by an organic solvent. However, other, unspecified, reagents may be used with this test method to extract other matrix material types for the same purposes.
1.3 Alternate techniques for determining matrix and reinforcement content include Test Methods D 3171 (matrix digestion), D 2584 (matrix burn-off/ignition), and D 3529/D 3529M (matrix dissolution). Test Method D 2584 is preferred for reinforcement materials, such as glass, quartz, or silica, that are unaffected by high-temperature environments.
1.4 The values stated in SI units are to be regarded as standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 9 and 7.2.3 and 8.2.1.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C613/C613M − 97(Reapproved 2008)
Standard Test Method for
Constituent Content of Composite Prepreg by Soxhlet
Extraction
This standard is issued under the fixed designation C613/C613M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision.Anumber 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.
1. Scope 2. Referenced Documents
1.1 This test method covers a Soxhlet extraction procedure 2.1 ASTM Standards:
to determine the matrix content, reinforcement content, and D883Terminology Relating to Plastics
filler content of composite material prepreg. Volatiles content, D2584Test Method for Ignition Loss of Cured Reinforced
if appropriate, and required, is determined by means of Test Resins
Method D3530/D3530M. D3171Test Methods for Constituent Content of Composite
1.1.1 The reinforcement and filler must be substantially Materials
insoluble in the selected extraction reagent and any filler must D3529/D3529MTest Method for Matrix Solids Content and
be capable of being separated from the reinforcement by Matrix Content of Composite Prepreg
filtering the extraction residue. D3530/D3530MTest Method for Volatiles Content of Com-
1.1.2 Reinforcement and filler content test results are total posite Material Prepreg
reinforcement content and total filler content; hybrid material D3878Terminology for Composite Materials
systems with more than one type of either reinforcement or E122PracticeforCalculatingSampleSizetoEstimate,With
filler cannot be distinguished. Specified Precision, the Average for a Characteristic of a
Lot or Process
1.2 This test method focuses on thermosetting matrix ma-
E177Practice for Use of the Terms Precision and Bias in
terial systems for which the matrix may be extracted by an
ASTM Test Methods
organic solvent. However, other, unspecified, reagents may be
E456Terminology Relating to Quality and Statistics
usedwiththistestmethodtoextractothermatrixmaterialtypes
E1309 Guide for Identification of Fiber-Reinforced
for the same purposes.
Polymer-Matrix Composite Materials in Databases
1.3 Alternate techniques for determining matrix and rein-
E1471Guide for Identification of Fibers, Fillers, and Core
forcement content include Test Methods D3171 (matrix
Materials in Computerized Material Property Databases
digestion), D2584 (matrix burn-off/ignition), and D3529/
2.2 NFPA Standard:
D3529M (matrix dissolution).Test Method D2584 is preferred
NFPA 86Standard for Ovens and Furnaces
forreinforcementmaterials,suchasglass,quartz,orsilica,that
are unaffected by high-temperature environments.
3. Terminology
1.4 The values stated in SI units are to be regarded as
3.1 Definitions—Terminology D3878 defines terms relating
standard.
to composite materials. Terminology D883 defines terms
1.5 This standard does not purport to address all of the
relating to plastics. Terminology E456 and Practice E177
safety concerns, if any, associated with its use. It is the
define terms relating to statistics. In the event of a conflict
responsibility of the user of this standard to establish appro-
between terms, Terminology D3878 shall have precedence
priate safety and health practices and determine the applica-
over the other documents.
bility of regulatory limitations prior to use. Specific precau-
3.1.1 matrix content, n—the amount of matrix present in a
tionary statements are given in Section 9 and 7.2.3 and 8.2.1.
composite or prepreg expressed either as percent by weight or
1 2
This test method is under the jurisdiction of ASTM Committee D30 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Composite Materialsand is the direct responsibility of Subcommittee D30.03 on contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Constituent/Precursor Properties. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved March 1, 2008. Published April 2008. Originally the ASTM website.
´1 3
approved in 1967. Last previous edition approved in 2003 as C613–97(2003) . Available from National Fire Protection Association (NFPA), 1 Batterymarch
DOI: 10.1520/C0613_C0613M-97R08. Park, Quincy, MA 02269-9101.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C613/C613M − 97 (2008)
percentbyvolume.Forpolymermatrixcompositesthisisresin 3.3.3 c—percent reinforcement mass change due to reagent
content. D3878 exposure.
3.1.2 prepreg, n—the admixture of fibrous reinforcement 3.3.4 CV—coefficient of variation statistic of a sample
andpolymericmatrixusedtofabricatecompositematerials.Its population for a given property.
form may be sheet, tape, or tow. For thermosetting matrices it
3.3.5 M —additional mass of filler in the test specimen.
a
has been partially cured to a controlled viscosity called “B
3.3.6 M —mass of the test specimen extraction residue.
e
stage”. D3878
3.3.7 M—initial mass of the test specimen.
i
3.1.3 resin content, n—see matrix content. D3878
3.3.8 M —mass of reinforcement in the test specimen.
r
3.1.4 sample, n—a small part or portion of a material or
3.3.9 n—number of replicates in the sample population.
product intended to be representative of the whole. D883
3.3.10 s —standard deviation statistic of a sample popu-
3.1.5 test result, n—the value obtained for a given property n−1
lation for a given property.
from one test unit.
3.1.5.1 Discussion—A test result may be a single observa-
3.3.11 W—weight percent of filler in prepreg.
f
tionoracombinationofanumberofobservationswhentwoor
3.3.12 W —weight percent of matrix in prepreg.
m
more test specimens are measured for each test.
3.3.13 W —weight percent of reinforcement in prepreg.
r
3.1.6 test specimen, n—a test unit or portion of a test unit
3.3.14 x—test result for an individual test specimen from
i
upon which a single or multiple observation is to be made.
the sample population for a given property.
3.1.7 test unit, n—a unit or portion of a material that is
3.3.15 x¯—average value of a sample population for a given
sufficienttoobtainatestresult(s)forthepropertyorproperties
property.
to be measured.
3.1.7.1 Discussion—A test unit may be a subunit of a
4. Summary of Test Method
primary (first stage) sampling unit or it may be a subunit of a
4.1 The exposed surface area of the prepreg material test
composite of primary sampling units or of increments from
specimenisincreasedbycuttingthetestspecimenintosmaller
these primary sampling units.
pieces. The test specimen is weighed and the matrix material
3.2 Definitions of Terms Specific to This Standard:
removedbymeansofSoxhletextraction.Theextractedresidue
3.2.1 dry resin content, n—prepreg resin content calculated
is dried and weighed. If a filler is present in the residue, in
by subtracting the average mass loss due to volatiles from the
addition to reinforcement, the two components are separated
initial test specimen mass.
by filtering the residue. From mass measurements of the initial
3.2.2 filler content, n—the amount of filler present in a test specimen, and of the residue taken at various stages in the
prepreg or composite expressed either as percent by weight or
process, the matrix content, reinforcement content, and filler
percent by volume. content are calculated and reported in weight percent.
3.2.2.1 Discussion—Inthistestmethodthereinforcementis 4.1.1 Soxhlet Process—While described in detail in com-
separated from the remainder of the material, which includes
mon quantitative chemical analysis textbooks, the Soxhlet
the matrix and the filler. If the filler is not then separated from process is summarized as follows. The test specimen is loaded
the matrix to determine the proportion of each, then the filler
into a filtering extraction thimble, which is placed into the
content is included in the matrix content. extraction chamber of a Soxhlet extraction assembly (see Fig.
1) containing an appropriate extraction reagent. The porous
3.2.3 reinforcement content, n—the amount of reinforce-
thimble allows the liquid extraction reagent to pass while
ment present in a composite or prepreg expressed either as
retaining the test specimen. Freshly distilled liquid reagent
percent by weight or percent by volume. This is sometimes
entersfromthetopoftheextractionchamber,fillingituntilthe
stated as a fraction, that is, reinforcement volume fraction.
3.2.4 replicate, n—a test specimen tested under nominally
identical conditions as other test specimens from the same
sample.
3.2.5 volatilescontent,n—theamountofvolatilespresentin
a prepreg expressed as percent by weight.
3.2.6 wetresincontent,n—prepregresincontentdetermined
by considering volatiles as part of the resin mass.
3.3 Symbols:
3.3.1 A—initial mass of dry reinforcement during a reagent
exposure evaluation.
3.3.2 B—final mass of dry reinforcement during a reagent
exposure evaluation.
See Form and Style for ASTM Standards. FIG. 1 Schematic of Soxhlet Extraction Apparatus
C613/C613M − 97 (2008)
liquid reaches the highest level of the reagent-return tube. At corrected by the process described in 14.4.5. The resulting
this moment the tube operates as a siphon, draining the correction may be used if this change is sufficiently reproduc-
extraction chamber completely as it returns the liquid reagent ible under the conditions of the test, and if this change has the
andanyextractedmaterialtoareservoirbeneaththeextraction samevalueforthereinforcementaloneasforthereinforcement
chamber. The heated reservoir boils the reagent, the vapor of in the matrix. Otherwise, a different reagent, or another test
which is led to a condenser placed above the extraction method, must be selected.
chamber. The distilled condensate then drips down into the
7. Apparatus
thimble,startingonceagaintheprocessoffillingtheextraction
chamber. The Soxhlet operation is not a continuous operation,
7.1 General Requirements:
but rather a sequence of fillings and siphonings, each cycle of
7.1.1 Container Volume—Asuggested volume is shown for
which is called a reflux change. The heat input and reagent
each container. However, other sizes may be required depend-
volumeareadjustedtocausetheboilingreagenttoreturntothe
ing upon the test specimen size, the amount of reagent needed
extraction flask from the condenser at 3 to 10 reflux changes
to complete the extraction process, and the relative sizes of
per hour, with the extraction continuing for a minimum of 4 h
related equipment.
or 20 reflux changes, whichever comes first.
7.1.2 Thermal Shock—Laboratory equipment that is sub-
4.1.2 Volatiles Content—Volatiles content is primarily ap-
jected to non-ambient temperatures (hot or cold) shall be of
plicable to thermosetting materials, and, if required, is deter-
tempered-glass or PTFE materials.
mined by Test Method D3530/D3530M. Volatiles content
7.1.3 Post-Test Elemental Analysis—If a post-test elemental
determinationrequiresdifferenttestspecimensthanthoseused
analysisoftheextractorresidueistobeperformed,laboratory
in the extraction process, since the process of determining
equipment contacting the test specimen shall be constructed of
volatiles content renders thermosetting material specimens
PTFEandtestspecimencuttingshallbelimitedtotoolsthatdo
unsuitable for subsequent organic solvent extraction.
not leave an elemental trace.
7.2 General Equipment:
5. Significance and Use
7.2.1 Analytical Balance—The analytical balance shall be
5.1 Theprepregvolatilescontent,matrixcontent,reinforce-
capable of reading to within 60.1 mg.
mentcontent,andfillercontentofcompositeprepregmaterials
7.2.2 MuffleFurnace—Themufflefurnaceusedtocondition
are used to control material manufacture and subsequent
glass extraction thimbles shall be capable of maintaining a
fabrication processes, and are key parameters in the specifica-
temperature of 510 6 15°C.
tion and production of such materials, as well as in the
7.2.3 Air-Circulating Drying Oven—The drying oven shall
fabrication of products made with such materials.
be capable of maintaining a temperature of 163 6 3°C.
(Warning—ForsafetypurposeslistedinNFPA86,takecareto
5.2 The extraction products resulting from this test method
limit volatile concentration in the oven by controlling sample
(the extract, the residue, or both) can be analyzed to assess
quantity, temperature, and ventilation.)
chemical composition and degree of purity.
7.2.4 Desiccator—The desiccator shall be capable of con-
6. Interferences taining the required test specimens.
6.1 Extent of Cure in Thermosetting Systems—The effi-
7.3 Extraction Assembly:
ciency of extraction for thermosetting matrix materials is 7.3.1 ExtractionThimbles—Theextractionthimblesshallbe
directlyrelatedtotheextentofcureoftheresinsystem.Resins
deep, narrow filtering cups, of either borosilicate glass in an
that have started to cross-link (such as B-staged resins) will be appropriate pore size, or fat-extracted cellulose paper, suitable
increasinglymoredifficulttoextractasthecureadvances.This
for use in the extraction chamber.
test method may not be appropriate for such materials; Test
7.3.2 Hot Plate—The hot plate shall have adjustable con-
Methods D3171 or D2584 may be better test method choices. trols suitable for heating the reagent within the reservoir flask
to 260°C and shall be capable of controlling the required
6.2 Reagent Selection—The proper reagent, in a suitable
reagent temperature within 615°C.
quantity, must be selected for the constituents under test. The
7.3.3 Reservoir Flask—The reservoir flask shall be of boro-
reagents listed in Section 8 are provided for consideration,
silicate glass, of suitable volume (125 mLis suggested) for the
particularly with regard to thermosetting materials, but cannot
reagent quantity and extraction chamber volume, and shall
be assured to perform well on all material systems within the
have a ground tapered joint capable of connection with the
scope of this test method.
remainder of the assembly.
6.3 Thimble Contamination—If the extract is to undergo
7.3.4 SoxhletExtractionChamber—Theextractionchamber
further analysis, the thimble must be clean to avoid a signifi-
shall be of borosilicate glass, with an automatic recycling
cant source of contamination.
siphon that recycles at a suitable liquid volume (50 mL is
6.4 Reinforcement Mass Change As a Result of Reagent— suggested),andwithagroundtaperedjointateachendcapable
The calculations of this test method assume that the reinforce- of connecting with the remainder of the assembly.
mentmass(orfiller,iffillerc
...
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