ASTM D1434-82(1998)
(Test Method)Standard Test Method for Determining Gas Permeability Characteristics of Plastic Film and Sheeting
Standard Test Method for Determining Gas Permeability Characteristics of Plastic Film and Sheeting
SCOPE
1.1 This test method covers the estimation of the steady-state rate of transmission of a gas through plastics in the form of film, sheeting, laminates, and plastic-coated papers or fabrics. This test method provides for the determination of (1) gas transmission rate (GTR), (2) permeance, and, in the case of homogeneous materials, (3) permeability.
1.2 Two procedures are provided:
1.2.1 Procedure M- Manometric.
1.2.2 Procedure V- Volumetric.
1.3 The values stated in SI units are to be regarded as the standard.
1.4 This standard does not purport to address all of the safety problems, 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.>
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Designation:D1434–82 (Reapproved 1998)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Determining Gas Permeability Characteristics of Plastic Film
and Sheeting
This standard is issued under the fixed designation D1434; 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.
1. Scope of the film. The SI unit of permeance is 1 mol/ (m ·s·Pa). The
test conditions (see 5.1) must be stated.
1.1 This test method covers the estimation of the steady-
3.1.3 permeability,P—theproductofthepermeanceandthe
state rate of transmission of a gas through plastics in the form
thickness of a film. The permeability is meaningful only for
of film, sheeting, laminates, and plastic-coated papers or
homogeneous materials, in which it is a property characteristic
fabrics. This test method provides for the determination of (1)
of the bulk material. This quantity should not be used unless
gastransmissionrate(GTR),(2)permeance,and,inthecaseof
the constancy of the permeability has been verified using
homogeneous materials, (3) permeability.
severaldifferentthicknessesofthematerial.TheSIunitofPis
1.2 Two procedures are provided:
1 mol/(m·s·Pa). The test conditions (see 3.1) must be stated.
1.2.1 Procedure M— Manometric.
1.2.2 Procedure V— Volumetric.
NOTE 1—One millilitre (STP) is 44.62 µmol, one atmosphere is 0.1013
1.3 The values stated in SI units are to be regarded as the MPa, and one day is 86.4310 s. GTR in SI units is obtained by
−10
multiplying the value in inch-pound units by 5.160310 . Additional
standard.
units and conversions are shown in Appendix X1.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1.4 steady state—the state attained when the amount of
responsibility of the user of this standard to establish appro-
gas absorbed in the film is in equilibrium with the flux of gas
priate safety and health practices and determine the applica-
through the film. For MethodVthis is obtained when the GTR
bility of regulatory limitations prior to use.
is constant.
2. Referenced Documents
4. Summary of Test Method
2.1 ASTM Standards:
4.1 The sample is mounted in a gas transmission cell so as
D618 Practice for Conditioning Plastics for Testing
to form a sealed semibarrier between two chambers. One
D1898 Practice for Sampling of Plastics
chamber contains the test gas at a specific high pressure, and
theotherchamber,atalowerpressure,receivesthepermeating
3. Terminology
gas. Either of the following procedures is used:
3.1 Definitions of Terms Specific to This Standard:
4.1.1 Procedure M— In Procedure M the lower pressure
3.1.1 gas transmission rate, GTR— the quantity of a given
chamber is initially evacuated and the transmission of the gas
gas passing through a unit of the parallel surfaces of a plastic
through the test specimen is indicated by an increase in
film in unit time under the conditions of test. The SI unit of
pressure.
GTR is 1 mol/(m ·s). The test conditions, including tempera-
4.1.2 Procedure V— In Procedure V the lower pressure
ture and partial pressure of the gas on both sides of the film,
chamber is maintained near atmospheric pressure and the
must be stated. Other factors, such as relative humidity and
transmission of the gas through the test specimen is indicated
hydrostatic pressure, that influence the transport of the gas
by a change in volume.
must also be stated.The inch-pound unit of GTR, a commonly
5. Significance and Use
used unit of GTR, is 1 mL (STP)/(m ·d) at a pressure
differential of one atmosphere.
5.1 Thesemeasurementsgivesemiquantitativeestimatesfor
3.1.2 permeance, P—the ratio of the gas transmission rate
the gas transmission of single pure gases through film and
to the difference in partial pressure of the gas on the two sides
sheeting. Correlation of measured values with any given use,
such as packaged contents protection, must be determined by
This test method is under the jurisdiction ofASTM Committee F-2 on Flexible experience. The gas transmission rate is affected by conditions
Barrier Materials and is the direct responsibility of Subcommittee F02.30 on Test
not specifically provided for in these tests, such as moisture
Methods.
content (Note 2), plasticizer content, and nonhomogeneities.
Current edition approved July 30, 1982. Published November 1982. Originally
published as D1434–56T. Last previous edition D1434–75. These tests do not include any provision for testing seals that
Annual Book of ASTM Standards, Vol 08.01.
may be involved in packaging applications.
Discontinued, see 1997 Annual Book of ASTM Standards, Vol. 08.01.
D1434
NOTE 2—The tests are run using gas with 0% moisture changes.
5.2 Interlaboratory testing has revealed that permeances
measured by these procedures exhibit a strong dependence on
the procedure being used, as well as on the laboratory
performing the testing. Agreement with other methods is
sometimes poor and may be material-dependent.The materials
being tested often affect the between-laboratory precision. The
causes of these variations are not known at this time. It is
suggested that this method not be used for referee purposes
unless purchaser and seller can both establish that they are
measuringthesamequantitytoamutuallyagreeduponlevelof
precision.
5.3 Use of the permeability coefficient (involving conver-
sionofthegastransmissionratetoaunitthicknessbasis)isnot
recommended unless the thickness-to-transmission rate rela-
tionship is known from previous studies. Even in essentially
homogeneous structures, variations in morphology (as indi-
FIG. 1 Manometric Gas Transmission Cell
cated, for example, by density) and thermal history may
influence permeability.
MANOMETRIC VISUALDETERMINATION
6. Test Specimen
9. Apparatus
6.1 Thetestspecimenshallberepresentativeofthematerial,
9.1 The apparatus shown in Fig. 1 and Fig. 2 consists of the
free of wrinkles, creases, pinholes, and other imperfections,
following items:
and shall be of uniform thickness. The test specimen shall be
9.1.1 Cell Manometer System—The calibrated cell manom-
cuttoanappropriatesize(generallycircular)tofitthetestcell.
eter leg, which indicates the pressure of transmitted gas, shall
6.2 The thickness of the specimen shall be measured to the
consist of precision-bore glass capillary tubing at least 65 mm
nearest 2.5 µm (0.1 mil) with a calibrated dial gage (or
long with an inside diameter of 1.5 mm.
equivalent) at a minimum of five points distributed over the
9.1.2 Cell Reservoir System, consisting of a glass reservoir
entire test area. Maximum, minimum, and average values
of sufficient size to contain all the mercury required in the cell.
should be recorded. An alternative measure of thickness
9.1.3 Adapters—Solid and hollow adapters for measure-
involving the weighing of a known area of specimens having a
ment of widely varying gas transmission rates. The solid
known density is also suitable for homogeneous materials.
adapter provides a minimum void volume for slow transmis-
sion rates. The hollow adapter increases the void volume by
7. Conditioning
about a factor of eight for faster transmission rates.
7.1 Standard Conditioning—Condition all test specimens at
9.1.4 Cell Vacuum Valve, capable of maintaining a vacuum-
236 2°C (73.46 3.6°F) in a desiccator over calcium chloride 5
tight seal.
or other suitable desiccant for not less than 48 h prior to test in
9.1.5 Plate Surfaces, that contact the specimen and filter
accordance with Practice D618, for those tests where condi-
paper shall be smooth and flat.
tioning is required. In cases of disagreement, the tolerances
9.1.6 O-Ring, for sealing the upper and lower plates.
shall be 6 1°C (6 1.8°F).
9.1.7 Pressure Gage, mechanical or electrical type with a
7.2 Alternative Conditioning—Alternatives to 7.1 may be
range from 0 to 333 kPa absolute. Used for measuring
used for conditioning the specimens provided that these
upstream gas pressure.
conditions are described in the report.
9.1.8 Barometer, suitable for measuring the pressure of the
atmosphere to the nearest 133 Pa.
8. Sampling
9.1.9 Vacuum Gage, to register the pressure during evacua-
8.1 The techniques used in sampling a batch of material to
tion of the system to the nearest 13 Pa.
be tested by these procedures must depend upon the kind of
9.1.10 Vacuum Pump, capable of reducing the pressure in
information that is sought. Care should be taken to ensure that
the system to 26 Pa or less.
samples represent conditions across the width and along the
9.1.11 Needle Valve, for slowly admitting and adjusting the
length of rolls of film. Practice D1898 provides guidelines for
pressure of the test gas.
deciding what procedures to use in sampling a batch of
9.1.12 Cathetometer, to measure the height of mercury in
material. Enough specimens must be tested to ensure that the
the cell manometer leg accurately. This instrument should be
information obtained is representative of the batch or other lot
capable of measuring changes to the nearest 0.5 mm.
size being tested.
TheDowgastransmissioncellsuppliedbyCustomScientificInstruments,Inc.,
PROCEDURE M
Whippany, NJ, has been found satisfactory for this purpose.
(Pressurechangesinthemanometriccellmaybedetermined 1
The Demi-G Valve ( ⁄4-in. IPS) manufactured by G. W. Dahl Co., Inc., Bristol,
by either visual or automatic recording.) RI, or a precision-ground glass stopcock, meets this requirement.
D1434
A—Supporting Legs
FIG. 3 Cell Manometer with Test Specimen in Place
B—Lower Plate
C—Upper Plate
(5) Wash with distilled water (to remove nitric acid).
D—Adapter
E—Vacuum Valve
(6) Wash with acetone (to remove water).
FIG. 2 Schematic View of Gas Transmission Cell
(7) Dry the cell at room temperature or by blowing a small
amount of clean dry air through it.
9.1.13 Micrometer, to measure specimen thickness, gradu-
11. Calibration
ated to 2.5 µm (0.1 mil) or better.
11.1 Eachcellshouldbecalibratedatthetesttemperatureas
9.1.14 Elevated-Temperature Fittings—Special cell fittings
follows (Fig. 3):
are required for high-temperature testing.
11.1.1 Determine the void volume of the filter paper from
the absolute density of its fiber content (Note 3), the weight of
10. Materials
the filter paper, and its apparent volume (Note 4). Express the
10.1 Test Gas—Thetestgasshallbedryandpure.Theratio
void volume determined in this way in microlitres and desig-
of the volume of gas available for transmission to the volume
nate as V .
CD
of gas transmitted at the completion of the test shall be at least
100:1.
NOTE 3—Any high-grade, medium-retention qualitative nonashing cel-
10.2 Mercury—Mercury used in the cell shall be triple lulosicfilterpaper,90mmindiameterwillbesatisfactoryforthispurpose.
Cellulose fiber has an approximate density of 1.45 g/mL.
distilled, checked regularly for purity, and replaced with clean
NOTE 4—The apparent volume may be calculated from the thickness
mercury when necessary.
and diameter of the filter paper.
10.2.1 Caution—Verylowconcentrationsofmercuryvapor
11.1.2 Determine the volume of the cell manometer leg
in the air are known to be hazardous. Guidelines for using
from B to C, Fig. 3, by mercury displacement. (Since the void
mercury in the laboratory have been published by Steere. Be
volume of the adapters is included in this part of the calibra-
sure to collect all spilled mercury in a closed container.
tion,thevolumefromBtoCshouldbedeterminedtwice,once
Transfers of mercury should be made over a large plastic tray.
withthesolidadapterinplace,andoncewiththehollow.)This
Under normal daily laboratory-use conditions, the cells should
volume is obtained by dividing the weight of the mercury
be cleaned about every 3 months. Dirty mercury is indicated
displaced by its density (Note 5). Determine this volume to
when the drop of the capillary becomes erratic or when
nearest 1 µL and designate as V .
mercury clings to the side of the capillary, or both. Whenever BC
suchdiscontinuitiesoccur,themercuryshouldberemovedand
NOTE 5—The density of mercury at 23°C is 13.54 g/mL.
the cell cleaned as follows:
11.1.3 Determine the volume, in microlitres, of the cell
(1) Wash with toluene (to remove greases and oils).
manometer leg from A to B, Fig. 3, by mercury displacement.
(2) Wash with acetone (to remove toluene).
Determine the average cross-sectional area of the capillary by
(3) Wash with distilled water (to remove acetone).
dividingthisvolumebythelength(expressedtothenearest0.1
(4) Wash with a 1+1 mixture of nitric acid and distilled
mm) from A to B. Determine this area to the nearest 0.01 mm
water (to remove any mercury salts that may be present). This
and designate as a .
c
operation may be repeated if necessary in order to ensure
11.1.4 Determine the area of the filter paper cavity to the
complete cleaning of glassware.
nearest 1 mm . Designate this area as A, the area of transmis-
sion.
11.1.5 Pourthemercuryfromthereservoirintothemanom-
Steere, N. E. “Mercury Vapor Hazards and Control Measures” in Handbook of
Laboratory Safety, N. V. Steere, Ed., CRC Press Inc., Boca Raton, FL, 1979. eterofthecellbycarefullytippingthecell.Recordthedistance
D1434
12.10 Reevacuate the system in the same manner as 12.8.
The cell manometer system should be evacuated to a pressure
of 26 Pa or less, as indicated on the vacuum gage.
12.11 Pour mercury from the reservoir into the manometer
system of the cell by carefully tipping the cell. The height of
the mercury in the capillary leg should be at approximately the
same level as line B (Fig. 3) and stationary.
NOTE 6—A leak is indicated if the height of the mercury does not
remainstationary.Ifsuchaleakoccurs,discontinuethetestandrepeatthe
entire procedure. (If a leak occurs on a second trial, this may indicate a
mechanical failure of the equipment.)
12.12 Record the height of the mercury in the capillary leg,
h , at the start of each test, that is, immediately before the test
o
gas has been admitted to the top of the cell.
12.13 After a suitable estimated time for attaining steady-
state conditions, record the height of the mercury in the
capillary leg, h , to the nearest 0.5 mm and the elapsed time, t
o
o, to the nearest 1 min.
FIG. 4 Component Arrangement of Gas Transmission Equipment
12.14 Record the height of the mercury
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