1、Designation: D 1434 82 (Reapproved 2009)1Standard Test Method forDetermining Gas Permeability Characteristics of Plastic Filmand Sheeting1This standard is issued under the fixed designation D 1434; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEUnits information was revised editorially in May 2009.1. Scope1.1 This test method covers the esti
3、mation of the steady-state rate of transmission of a gas through plastics in the formof film, sheeting, laminates, and plastic-coated papers orfabrics. This test method provides for the determination of (1)gas transmission rate (GTR), (2) permeance, and, in the case ofhomogeneous materials, (3) perm
4、eability.1.2 Two procedures are provided:1.2.1 Procedure MManometric.1.2.2 Procedure VVolumetric.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any
5、, 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.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for Testin
6、gD 1898 Practice for Sampling of Plastics33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 gas transmission rate, GTR the quantity of a givengas passing through a unit of the parallel surfaces of a plasticfilm in unit time under the conditions of test. The SI unit ofGTR is 1 mo
7、l/(m2s). The test conditions, including tempera-ture and partial pressure of the gas on both sides of the film,must be stated. Other factors, such as relative humidity andhydrostatic pressure, that influence the transport of the gasmust also be stated. The inch-pound unit of GTR, a commonlyused unit
8、 of GTR, is 1 mL (STP)/(m2d) at a pressuredifferential of one atmosphere.3.1.2 permeance, Pthe ratio of the gas transmission rateto the difference in partial pressure of the gas on the two sidesof the film. The SI unit of permeance is 1 mol/ (m2sPa). Thetest conditions (see 5.1) must be stated.3.1.3
9、 permeability, Pthe product of the permeance and thethickness of a film. The permeability is meaningful only forhomogeneous materials, in which it is a property characteristicof the bulk material. This quantity should not be used unlessthe constancy of the permeability has been verified usingseveral
10、 different thicknesses of the material. The SI unit of P is1 mol/(msPa). The test conditions (see 3.1) must be stated.NOTE 1One millilitre (STP) is 44.62 mol, one atmosphere is 0.1013MPa, and one day is 86.4 3 103s. GTR in SI units is obtained bymultiplying the value in inch-pound units by 5.160 3 1
11、010. Additionalunits and conversions are shown in Appendix X1.3.1.4 steady statethe state attained when the amount ofgas absorbed in the film is in equilibrium with the flux of gasthrough the film. For Method V, this is obtained when the GTRis constant.4. Summary of Test Method4.1 The sample is moun
12、ted in a gas transmission cell so asto form a sealed semibarrier between two chambers. Onechamber contains the test gas at a specific high pressure, andthe other chamber, at a lower pressure, receives the permeatinggas. Either of the following procedures is used:4.1.1 Procedure MIn Procedure M the l
13、ower pressurechamber is initially evacuated and the transmission of the gasthrough the test specimen is indicated by an increase inpressure.1This test method is under the jurisdiction ofASTM Committee F02 on FlexibleBarrier Packaging and is the direct responsibility of Subcommittee F02.10 onPermeati
14、on.Current edition approved May 1, 2009. Published June 2009. Originallyapproved in 1956. Last previous edition approved in 2003 as D 1434 82(2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandar
15、ds volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.1.2 Procedure VIn Procedure V the lower pressurechamber is maintained near atmospheri
16、c pressure and thetransmission of the gas through the test specimen is indicatedby a change in volume.5. Significance and Use5.1 These measurements give semiquantitative estimates forthe gas transmission of single pure gases through film andsheeting. Correlation of measured values with any given use
17、,such as packaged contents protection, must be determined byexperience. The gas transmission rate is affected by conditionsnot specifically provided for in these tests, such as moisturecontent (Note 2), plasticizer content, and nonhomogeneities.These tests do not include any provision for testing se
18、als thatmay be involved in packaging applications.NOTE 2The tests are run using gas with 0 % moisture changes.5.2 Interlaboratory testing has revealed that permeancesmeasured by these procedures exhibit a strong dependence onthe procedure being used, as well as on the laboratoryperforming the testin
19、g. Agreement with other methods issometimes poor and may be material-dependent. The materialsbeing tested often affect the between-laboratory precision. Thecauses of these variations are not known at this time. It issuggested that this method not be used for referee purposesunless purchaser and sell
20、er can both establish that they aremeasuring the same quantity to a mutually agreed upon level ofprecision.5.3 Use of the permeability coefficient (involving conver-sion of the gas transmission rate to a unit thickness basis) is notrecommended unless the thickness-to-transmission rate rela-tionship
21、is known from previous studies. Even in essentiallyhomogeneous structures, variations in morphology (as indi-cated, for example, by density) and thermal history mayinfluence permeability.6. Test Specimen6.1 The test specimen shall be representative of the material,free of wrinkles, creases, pinholes
22、, and other imperfections,and shall be of uniform thickness. The test specimen shall becut to an appropriate size (generally circular) to fit the test cell.6.2 The thickness of the specimen shall be measured to thenearest 2.5 m with a calibrated dial gage (or equivalent) at aminimum of five points d
23、istributed over the entire test area.Maximum, minimum, and average values should be recorded.An alternative measure of thickness involving the weighing ofa known area of specimens having a known density is alsosuitable for homogeneous materials.7. Conditioning7.1 Standard ConditioningCondition all t
24、est specimens at23 6 2C in a desiccator over calcium chloride or othersuitable desiccant for not less than 48 h prior to test inaccordance with Practice D 618, for those tests where condi-tioning is required. In cases of disagreement, the tolerancesshall be 61C.7.2 Alternative ConditioningAlternativ
25、es to 7.1 may beused for conditioning the specimens provided that theseconditions are described in the report.8. Sampling8.1 The techniques used in sampling a batch of material tobe tested by these procedures must depend upon the kind ofinformation that is sought. Care should be taken to ensure that
26、samples represent conditions across the width and along thelength of rolls of film. Practice D 1898 provides guidelines fordeciding what procedures to use in sampling a batch ofmaterial. Enough specimens must be tested to ensure that theinformation obtained is representative of the batch or other lo
27、tsize being tested.PROCEDURE M(Pressure changes in the manometric cell may be determinedby either visual or automatic recording.)MANOMETRIC VISUAL DETERMINATION9. Apparatus9.1 The apparatus shown in Fig. 1 and Fig. 2 consists of thefollowing items:49.1.1 Cell Manometer SystemThe calibrated cell mano
28、m-eter leg, which indicates the pressure of transmitted gas, shallconsist of precision-bore glass capillary tubing at least 65 mmlong with an inside diameter of 1.5 mm.9.1.2 Cell Reservoir System, consisting of a glass reservoirof sufficient size to contain all the mercury required in the cell.9.1.3
29、 AdaptersSolid and hollow adapters for measure-ment of widely varying gas transmission rates. The solidadapter provides a minimum void volume for slow transmis-sion rates. The hollow adapter increases the void volume byabout a factor of eight for faster transmission rates.4The sole source of supply
30、of the apparatus (Dow gas transmission cell) knownto the committee at this time is Custom Scientific Instruments, Inc., Whippany, NJ.If you are aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameet
31、ing of the responsible technical committee,1which you may attend.FIG. 1 Manometric Gas Transmission CellD 1434 82 (2009)129.1.4 Cell Vacuum Valve, capable of maintaining a vacuum-tight seal.59.1.5 Plate Surfaces, that contact the specimen and filterpaper shall be smooth and flat.9.1.6 O-Ring, for se
32、aling the upper and lower plates.9.1.7 Pressure Gage, mechanical or electrical type with arange from 0 to 333 kPa absolute. Used for measuringupstream gas pressure.9.1.8 Barometer, suitable for measuring the pressure of theatmosphere to the nearest 133 Pa.9.1.9 Vacuum Gage, to register the pressure
33、during evacua-tion of the system to the nearest 13 Pa.9.1.10 Vacuum Pump, capable of reducing the pressure inthe system to 26 Pa or less.9.1.11 Needle Valve, for slowly admitting and adjusting thepressure of the test gas.9.1.12 Cathetometer, to measure the height of mercury inthe cell manometer leg
34、accurately. This instrument should becapable of measuring changes to the nearest 0.5 mm.9.1.13 Micrometer, to measure specimen thickness, gradu-ated to 2.5 m (0.1 mil) or better.9.1.14 Elevated-Temperature FittingsSpecial cell fittingsare required for high-temperature testing.10. Materials10.1 Test
35、GasThe test gas shall be dry and pure. The ratioof the volume of gas available for transmission to the volumeof gas transmitted at the completion of the test shall be at least100:1.10.2 MercuryMercury used in the cell shall be tripledistilled, checked regularly for purity, and replaced with cleanmer
36、cury when necessary.10.2.1 WarningVery low concentrations of mercury vaporin the air are known to be hazardous. Guidelines for usingmercury in the laboratory have been published by Steere.6Besure to collect all spilled mercury in a closed container.Transfers of mercury should be made over a large pl
37、astic tray.Under normal daily laboratory-use conditions, the cells shouldbe cleaned about every 3 months. Dirty mercury is indicatedwhen the drop of the capillary becomes erratic or whenmercury clings to the side of the capillary, or both. Wheneversuch discontinuities occur, the mercury should be re
38、moved andthe cell cleaned as follows:(1) Wash with toluene (to remove greases and oils).(2) Wash with acetone (to remove toluene).(3) Wash with distilled water (to remove acetone).(4) Wash with a 1 + 1 mixture of nitric acid and distilledwater (to remove any mercury salts that may be present). Thiso
39、peration may be repeated if necessary in order to ensurecomplete cleaning of glassware.(5) Wash with distilled water (to remove nitric acid).(6) Wash with acetone (to remove water).(7) Dry the cell at room temperature or by blowing a smallamount of clean dry air through it.11. Calibration11.1 Each c
40、ell should be calibrated at the test temperature asfollows (Fig. 3):11.1.1 Determine the void volume of the filter paper fromthe absolute density of its fiber content (Note 3), the weight ofthe filter paper, and its apparent volume (Note 4). Express thevoid volume determined in this way in microlitr
41、es and desig-nate as VCD.5The sole source of supply of the apparatus (Demi-G Valve (14-in. IPS) knownto the committee at this time is G. W. Dahl Co., Inc., Bristol, RI. If you are awareof alternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will rec
42、eive careful consideration at a meeting of theresponsible technical committee,1which you may attend.6Steere, N. E. “Mercury Vapor Hazards and Control Measures” in Handbook ofLaboratory Safety, N. V. Steere, Ed., CRC Press Inc., Boca Raton, FL, 1979.ASupporting LegsBLower PlateCUpper PlateDAdapterEVa
43、cuum ValveFIG. 2 Schematic View of Gas Transmission CellFIG. 3 Cell Manometer with Test Specimen in PlaceD 1434 82 (2009)13NOTE 3Any high-grade, medium-retention qualitative nonashing cel-lulosic filter paper, 90 mm in diameter will be satisfactory for this purpose.Cellulose fiber has an approximate
44、 density of 1.45 g/mL.NOTE 4The apparent volume may be calculated from the thicknessand diameter of the filter paper.11.1.2 Determine the volume of the cell manometer legfrom B to C, Fig. 3, by mercury displacement. (Since the voidvolume of the adapters is included in this part of the calibra-tion,
45、the volume from B to C should be determined twice, oncewith the solid adapter in place, and once with the hollow.) Thisvolume is obtained by dividing the weight of the mercurydisplaced by its density (Note 5). Determine this volume tonearest 1 L and designate as VBC.NOTE 5The density of mercury at 2
46、3C is 13.54 g/mL.11.1.3 Determine the volume, in microlitres, of the cellmanometer leg from A to B, Fig. 3, by mercury displacement.Determine the average cross-sectional area of the capillary bydividing this volume by the length (expressed to the nearest 0.1mm) from A to B. Determine this area to th
47、e nearest 0.01 mm2and designate as ac.11.1.4 Determine the area of the filter paper cavity to thenearest 1 mm2. Designate this area as A, the area of transmis-sion.11.1.5 Pour the mercury from the reservoir into the manom-eter of the cell by carefully tipping the cell. Record the distancefrom the da
48、tum plane to the upper calibration line B in thecapillary leg as hB. Record the distance from the datum planeto the top of the mercury meniscus in the reservoir leg as hL.Determine hBand hLto the nearest 0.5 mm.11.2 NBS Standard Reference Material 14707is a polyesterfilm whose permeance to oxygen ga
49、s has been certified for arange of experimental conditions. The calibration steps in 11.1can be verified by comparing measurements obtained using thismethod of test in the users laboratory with the values providedon the certificate accompanying the SRM.12. Procedure12.1 Transfer all the mercury into the reservoir of the cellmanometer system by carefully tipping the cell in such a waythat the mercury pours into the reservoir.12.2 Insert the appropriate adapter in the cell body.12.3 Center a filter paper in the lower plate cavity.12.4
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1