ASTM D5492-98(2003)e1
(Test Method)Standard Test Method for Determination of Xylene Solubles in Propylene Plastics
Standard Test Method for Determination of Xylene Solubles in Propylene Plastics
SCOPE
1.1 This test method is to be used for determining the 25°C ortho-xylene-soluble fraction of polypropylene and propylene-ethylene copolymers.
1.2 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.
Note 1—This standard is similar to ISO 6427-1982 in title only. The technical content is significantly different.
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Designation:D 5492–98 (Reapproved 2003)
Standard Test Method for
Determination of Xylene Solubles in Propylene Plastics
This standard is issued under the fixed designation D 5492; the number immediately following the designation indicates the year of
original adoption or, in the case 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.
e NOTE—Changed the ISO equivalency statement in Note 1 in November 2003.
1. Scope 4. Summary of Test Method
1.1 This test method is to be used for determining the 25°C 4.1 Aweighedamountofsampleisdissolvedinorthoxylene
ortho-xylene-soluble fraction of polypropylene and propylene- under reflux conditions. The solution is cooled under con-
ethylene copolymers. trolled conditions and maintained at a 25°C equilibrium
1.2 This standard does not purport to address all of the temperature so that the crystallization of the insoluble fraction
safety concerns, if any, associated with its use. It is the takes place. One of two precipitation-time periods can be used,
responsibility of the user of this standard to establish appro- although the longer precipitation time should be used for
priate safety and health practices and determine the applica- homopolymersandcopolymerswithsolubleslessthan12mass
bility of regulatory limitations prior to use. %. When the solution is cooled the insoluble portion precipi-
tatesandisisolatedbyfiltration.Theorthoxyleneisevaporated
NOTE 1—There is no similar or equivalent ISO standard at this time.A
fromthefiltrate,leavingthesolublefractionintheresidue.The
technical equivalent is currently under consideration in the work program
percentage of this fraction in the plastic is determined gravi-
of ISO TC61, SC9, WG6.
metrically.
2. Referenced Documents
5. Significance and Use
2.1 ASTM Standards:
5.1 The results of this test provide a relative measure of the
D 883 Terminology Relating to Plastics
total soluble fraction of polypropylene and copolymers. The
D 1600 Terminology of Abbreviated Terms Relating to
soluble fraction can be approximately correlated to the amor-
Plastics
phous fraction in the polypropylene. Xylene is widely used for
2.2 ISO Standard:
determiningthesolublefractioninpolypropylene.Theconcen-
ISO 6427-1982 Plastics—Determination of Matter Ex-
trationofasolublefractionobtainedwithaspecificsolventhas
tracted by Organic Solvents (Conventional Methods) An-
been found to relate closely to the performance characteristics
nex B Standard Method of Test for Determination of
of a product in certain applications, for example film and fiber.
Polypropylene Solubility in Cold Xylene
Data obtained by one solvent and at one precipitation time
3. Terminology
cannot be compared with data obtained by another solvent or
precipitation time, respectively. Xylene is more specific to the
3.1 For definitions of plastic terms see Terminology D 883
atactic fraction than other solvents.
and for abbreviations see Terminology D 1600.
3.2 There are no terms in this test method that require new
6. Interferences
or other-than-dictionary definitions.
6.1 Materials with solubilities similar to the polymer frac-
tion, such as additives, may interfere with the measurement of
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
solubles. When present in concentrations that are judged to
and is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materi-
impart a significant error to the soluble-fraction data, the level
als.
Current edition approved November 1, 2003. Published December 2003.
of interference must be determined and corrections made.
Originally approved in 1994. Last previous edition approved in 1998 as D 5492 -
6.2 Small-particle fillers and pigments that may pass
98.
2 throughthefilterandinsolublegelspresentinthepolymermay
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
cause errors in the measurement.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
6.3 The polymer flakes and spheres must be dried before
the ASTM website.
testing to eliminate moisture that can influence the initial
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
weight of sample added to the flask.
4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D 5492–98 (2003)
NOTE 3—It is recommended that o-xylene be purchased in glass or
7. Apparatus
glass-lined containers and of a size such that the o-xylene will be used
7.1 Reflux-Condenser Apparatus, 400 mm, with 24/40 glass
within three days, once opened. Containers of larger size may be used if
joint.
the o-xylene is used up within a short period of time. The purpose of the
7.2 Flat-Bottom Boiling Flask, with one or two necks, 400
short time period is to ensure purity and minimize moisture pickup and
mL with 24/40 joint, Erlenmeyer flask, or cylindrical bottle. other contaminants.
7.3 Insulation Disk, made of fiberglass or rock wool.
9.2.2 Pipet 200 mL of unstabilized or stabilized o-xylene
7.4 Electromagnetic Stirrer, with temperature-controlled
into a clean empty flask.
heating plate, thermostated oil bath, or heater block capable of
9.2.3 Place a 200-mm No. 4 filter paper or equivalent in a
maintaining 145 to 150°C.
200-mmfunnelinafunnelrackovera250-mLglass-stoppered
7.5 Stirring Bar.
flask.
7.6 Pipette, Class A, 200 mL.
9.2.4 For each sample blank, pour the contents from the
7.7 Pipette, Class A, 100 mL.
flask into a funnel and allow the filtrate to drip into a second
7.8 Glass-Stoppered Volumetric Flask, 250 mL.
flask. Continue the filtration until all the filtrate has been
7.9 Thermostatically Controlled Water Bath, at 25°C.
collected.
7.10 Electromagnetic Stirrers.
4 9.2.5 Dry the aluminum pans for 30 min in an oven at
7.11 Filter Paper, fluted, Whatman No. 4, No. 541, or
150°C. Cool the pans in a desiccator until ready to use. For
equivalent, 200 mm.
eachsampleweighaclean,drypanontheanalyticalbalanceto
7.12 Funnel, 60°, 200 mm.
the nearest 0.0001 g.
7.13 Heated Vacuum Oven.
9.2.6 With a Class A pipette, pipet a 100-mL aliquot of the
7.14 Disposable Aluminum Pans, 300-mL capacity, with
filtered o-xylene into the weighed aluminum pan.
smooth sides.
9.2.7 Place the pan on a temperature-controlled heating
7.15 Temperature-Controlled Heating Plate.
plate maintained at 145 to 150°C. Allow the aliquot to obtain
7.16 Analytical Balance, with minimum weighing sensitiv-
a rolling boil to prevent splashing. Blanket the pan with a slow
ity to 0.0001 g (a sensitivity of 0.00001 is preferred).
stream of nitrogen. Continue heating the pan until the residue
7.17 Desiccator, containing appropriate desiccant.
in the dish is almost dry.
7.18 Timer with Alarms, in minutes.
9.2.8 Place the pan into a vacuum oven at 100 6 5°C for
8. Reagents about an hour at a pressure less than 13.3 kPa.
9.2.9 Cool the pan to room temperature in a desiccator and
8.1 Reagent-Grade Ortho-Xylene (o-Xylene)—Assay gas
weigh the pan to the nearest 0.0001 g. Repeat the drying,
chromatography (GC) = 98 % min; less than 2 % ethylbenzene
cooling, and weighing steps until two consecutive weighings
as established by GC; evaporation residue at 140°C less than
agree within 0.0002 g. Calculate the average blank-residual
0.002 g/100 mL; boiling point 144°C.
mass of the three determinations.
9. Procedure 9.3 Determine the Percent Soluble Fraction in the Polymer:
9.3.1 Dry the polypropylene powder or spheres before
9.1 Preparation of the o-Xylene:
analysis. It is not necessary to dry the pellets unless it is known
9.1.1 It is not necessary to stabilize the o-xylene before
that they contain high levels of moisture pellets or spheres
using, but it may be stabilized if desired.
beforeanalysis.Ifnecessary,drythesamplesinavacuumoven
5 6 7
NOTE 2—BHT, Irganox1010, andSantonoxR havebeenfoundtobe
at 70 6 5°C, in a vacuum of 13.3 kPa for a minimum of 20
effective stabilizers for o-xylene.
min. Cool the sample in a desiccator to prevent moisture
9.1.2 Degas the o-xylene. Using nitrogen gas, purge the
pickup.
o-xylene for a minimum of 1 h every 24 h.
NOTE 4—For large pellets or spheres, where there is concern that the
9.2 Determine the Level of Contamination in the o-Xylene
polymersamplewillnotdissolveinareasonabletimeframe,thepelletsor
(Solvent Blank):
spheresmaybegroundtoanappropriatesizetoaffordafasterdissolution.
9.2.1 The purpose of the solvent blank is to determine
Ground material should be dried as specified in 9.3.1.
whethertheo-xylenetobeusedcontainssignificantamountsof
9.3.2 Weigh out a sample in accordance withTable 1.When
evaporation residue or foreign components. A solvent-blank
the expected solubles level is unknown use a 2.0 6 0.1 g
test for residue should be run on every new lot of o-xylene.
sample. For referee testing between laboratories a sample
Run and average the solvent-blank results, for three aliquots
2.0 6 0.1 g shall be used, unless there is agreement between
per bottle or lot of o-xylene. Each aliquot shall be 200 mL.
the laboratories to use a different sample size. Determine mass
Available from Whatman Intn. Ltd., Maidstone, England or from Fisher
TABLE 1 Sample Size
Scientific, 711 Forbes Ave., Pittsburgh, PA 15219.
A
Available from Uniroyal Chemical Co., Inc., Specialty Chemicals Division,
Expected Solubles Initial Sample Mass, g
World Headquarters, Benson Rd., Middlebury, CT 06749.
6 <8 % by mass 4.0000 6 0.1000 or 2.000 6 0.1000
Available from CIBA-GEIGY Corp., Additive Division, Seven Skyline Drive,
8.0 to 30.0 % by mass 2.0000 6 0.1000
Hawthorne, NY 10532.
>30.0 % by mass 2.0000 6 0.1000 or 1.0000 6 0.1000
Available from Monsanto Co., Chemical Group, 800 N. Lindberg Blvd., St.
A
Louis, MO 63167. See Note 1.
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D 5492–98 (2003)
of the sample to the nearest 0.0001 g. Pour the sample into a 9.3.9 Remove the heating plate from beneath the flask.
flat-bottom boiling flask. Place a magnetic stirring bar in the Detach the flask from the condenser and lightly stopper the
flask. flask. Cool the solution temperature from reflux temperature to
below 100°C by cooling the flask in air for 12 to 14 min. A
NOTE 5—Table 1 provides a choice of sample mass. Use the largest
timer with alarm must be used to ensure that the solution is
sample mass possible to minimize variability of the test data, unless from
cooledtowithinanarrowrangeoftemperaturefromruntorun.
prior experience it is known that the polymer/o-xylene solution does not
filter readily as in 9.3.11. 9.3.10 Transfer the flask to a thermostatically controlled
water bath at 25 6 0.5°C. Shake the flask to break up any
9.3.3 Pipet 200 mL of unstabilized or stabilized o-xylene
precipitate before immersing the flask in the bath.
into the flask.
9.3.4 Attach the flask to the condenser.
NOTE 6—Becausetherateofcoolingaffectsthecrystalsizeandtherate
9.3.5 Place an insulation disk on top of the electromagnetic
of crystallization, the time and temperature during the cooling steps are
very critical, especially in the short method.
stirrer plate to prevent localized heating of the flask. Position
the flask and condenser system on top of the insulation disk NOTE 7—The water bath must have sufficient cooling capacity to
maintain a constant temperature of 25 6 0.5°C during cooling.
(see Fig. 1). Position the nitrogen inlet tube in the top of the
condenser. Turn on the cooling water to the condenser.
9.3.11 Precipitation Time:
9.3.6 Blanket the contents of the boiling flask with a slow
9.3.11.1 Long Precipitation Time—Allow the flask to stand
flow of nitrogen directed across the top of the condenser, not
undisturbed 16 to 20 h at 25 6 0.5°C. Stir or gently shake the
directly into the condenser, to minimize possible o-xylene loss.
flask to break up any precipitated-polymer gel at the end of the
Flow rate should be approximately 2 L/h.
precipitation time, or
9.3.7 Heat the polymer/o-xylene mixture to reflux tempera-
9.3.11.2 Short-Precipitation Time—Without stirring, cool
ture while vigorously stirring. The stirring shall be vigorous
the solution for 60 min in the temperature-controlled bath at
enough to obtain a deep vortex, which keeps the boiling under
25 6 0.5°C. Use a timer with an alarm to ensure that the
control and prevents boiling up into the condenser. This will
solution-precipitation time ranges from 60 to 62 min. Remove
take approximately 30 min. Ensure that the reflux is gentle so
the flask from the temperature-controlled bath. Stir or gently
that localized burning and sticking of the polymer to the flask
shake the flask to break up any precipitated-polymer gel.
walls does not occur.
9.3.8 Once the reflux temperature is reached, stir the solu- NOTE 8—The long-precipitation method should be used only for
homopolymers and copolymers with solubles of less than 12 %. Results
tion for an additional 30 min. The liquid will appear water-
have shown that copolymers with high levels of polymer solubles take as
clear.
muchasthreedaystoreachequilibrium,thereforelongprecipitationtimes
do not have any advantage over short precipitation times.
9.3.12 Place a 200-mm No. 4 filter paper or equivalent in a
200-mmfunnelinafunnelrackovera250-mLglass-stoppered
flask.
9.3.13 For each sample, pour the contents from the flask
into a funnel and allow the filtrate to drip into the second flask.
9.3.14 Continue the filtration until all the filtrate has been
collected. If the filtered solution is not completely clear it will
be necessary to repeat the filtration.
9.3.15 Dry the aluminum pans for 30 min in an oven at
150°C. Cool the pans in a desiccator until ready for use. For
eachsampleweighaclean,drypanontheanalyticalbalanceto
the nearest 0.0001 g.
9.3.16 With the clean Class A pipette, pipet a 100-mL
aliquot of the soluble filtrate into the weighed aluminum pan.
9.3.17 Place the pan on a temperature-controlled hot plate
maintained at 145 to 150°C. Allow the aliquot to obtain a
rolling boil to prevent splashing. Blanket the pan with a slow
stream of nitrogen. Continue heating the pan until the residue
in the dish is almost dry.
9.3.18 Place the pan in a vacuum oven at 100 6 5°C for
about an hour at a pressure less than 13.3 kPa.
9.3.19 Cool the pan to room temperature in a desiccator and
weigh the pan to the nearest 0.0001 g. Repeat the drying,
cooling, and weighing steps until two consecutive weighings
agree within 0.0002 g.
9.3.20 Obtainthemassofthesolublefractionbysubtracting
FIG. 1 Equipment Setup the mass of the pan from the residue-and-pan mass.Adjust the
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