1、Designation: D 7131 05An American National StandardStandard Test Method forDetermination of Ion Exchange Capacity (IEC) in GraftedBattery Separator1This standard is issued under the fixed designation D 7131; the number immediately following the designation indicates the year oforiginal adoption or,
2、in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method evaluates an important characteristic ofpolyolefin or other fib
3、rous nonwoven sheet material intendedfor use in alkaline battery separator applications. The hydro-philic properties of the material are enhanced by grafting afunctional group onto the polyolefin, and this test method is theprimary test method to determine the treatment level, that is,level of monom
4、er grafted to the base polymer. This test methodcan also be used for film or membranes1.2 This test method is intended primarily for testingcopolymer-grafted polyolefin materials used as battery separa-tors, but could be used for any grafted material. Theseseparators have radiation-initiated graftin
5、g of acrylic acidmonomer (for example) onto a polyolefin base-web material togenerate hydrophilic sites on the material. This process is avery good method for surface modification of polymer mate-rials, and is used to make separators hydrophilic. Grafting canbe accomplished by irradiation on common
6、polymers such aspolyethylene, polypropylene and fluoropolymers with variousforms of energy, such as UV, gamma rays, electron beams (EB)or X-rays1.3 The values stated in SI units are to be regarded as thestandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associa
7、ted with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and to determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 123 Terminology Relating to TextilesD 1711 Terminology Re
8、lating to Electrical InsulationE 438 Specification for Glasses in Laboratory ApparatusE 1272 Specification for Laboratory Glass Graduated Cyl-inders3. Terminology3.1 Definitions:3.1.1 For definitions of textile terms, refer to TerminologyD 123.3.1.2 For definitions of electrical terms, refer to Term
9、inol-ogy D 1711.3.2 Definitions of Terms Specific to This Standard:3.2.1 grafted battery separator, na sheet material whosefiber surface has been grafted to add a functional group to thebase polymer of the fiber by some form of radiation, whereasthese grafted sites are hydrophilic, thus increasing t
10、he sheetmaterials hydrophilic properties.3.2.2 ion-exchange capacity, nthe number of ionic siteson the separator fiber surface that can participate in theexchange process. The exchange capacity is expressed inmilliequivalents per gram.4. Summary of Test Method4.1 A predetermined amount of separator
11、in its acid form isadded to a bottle with a potassium hydroxide (KOH) solution.The specimens are conditioned under a controlled temperaturefor 2 h. After being allowed to cool, the amount of graftedmonomer functionality of the grafted surface in the sample canbe determined by titration.4.2 Results a
12、re calculated as milliequivalents per gram(meq/g) using the appropriate equations.4.3 Sampling must be determined based on experience withthe separators uniformity and consistency of the graftingprocess.5. Significance and Use5.1 Nickel-metal hydride (Ni-MH) cells have a tendency toexhibit high rate
13、s of self-discharge that may be caused bycontamination within a battery cell. The contamination sourcehas been shown to originate from electrode impurities. Graftedseparators can trap and hold these impurities, thus reducingself-discharge rates and enhancing battery quality. This test1This test meth
14、od is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.19 on Dielectric Sheet and Roll Products.Current edition approved March 1, 2005. Published March 2005.2For referenced ASTM standards, visit the ASTM
15、 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 website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United
16、 States.method determines an ionic exchange capacity that can be usedto quantify the level of grafting of a separator.5.2 This method is useful for research, quality control, andmaterial specifications.6. Apparatus6.1 Beaker, 600 mL.6.2 Bottles, Glass or HDPE, 125-mL capacity with screwcap.6.3 Cylin
17、der, Graduated, Class A, 100- mL capacity.NOTE 1The tolerance on the accuracy of the graduations in Specifi-cation E 1272 for this apparatus is 61.4 mL. If greater accuracy isrequired for a test result, the graduated trap(s) should be calibrated.6.4 Pipette, Volumetric, Class A, 10- mL capacity.NOTE
18、 2The tolerance on the accuracy of the graduations in Specifi-cation E 438 for this apparatus is 60.02 mL. If greater accuracy isrequired for a test result, the graduated trap(s) should be calibrated.6.5 Oven.7. Reagents and Materials7.1 Hydrochloric Acid, 0.1M (HCL), ACS grade.7.2 Hydrochloric Acid
19、, 1.0M (HCL), ACS grade.7.3 Methyl Red, ACS grade.7.4 Potassium Hydroxide, 0.1M (KOH), ACS grade.(WarningFollow appropriate safe handling procedureswhen using acids or bases.)7.5 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall r
20、eagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.38. Conditioning8.1 Cut test specimen to a weight of 0.50 6 0.05 g. Convertthe specimen into acid form by immersion in 1.0M HCl at 606 3 C for at least
21、 1 h.8.2 Wash the specimen with water so the pH, using litmuspaper, of the specimen is between a pH of 6 to 7.8.3 Dry the specimen to a constant weight (W1), recordingthe weight.8.4 For each specimen, add 90 6 0.5 mL of distilled waterto each bottle as described in 6.2.8.5 For each specimen, add 10
22、6 0.05 mL of 0.1M KOHusing the volumetric pipette (as described in 6.4) to the samebottles as in 8.4.8.6 Add the dried specimen to the conditioned bottles.8.7 Run a control, using the same instruction as stated in 8.4and 8.5 but without the test specimen.8.8 Bottles are then stored together at 60 C
23、for 2 to 2.5 h.9. Procedure9.1 Allow bottles to cool back to room temperature.9.2 The contents of each bottle are then transferred to aglass beaker as stated in 6.19.3 A further 100 mL of washings are added to the beakersfrom each bottle.9.4 The amount of KOH remaining in each bottle is deter-mined
24、through titration.10. Calculation or Interpretation of Results10.1 Calculate the IEC in meq/g as follows:IEC 5 t22 t1!/10W1! (1)Where:T1= the titration value of 0.1M HCl from the bottle withthe sample,T2= the titration value of 0.1M HCl from the bottlewithout the sample, andW1= the weight of the dri
25、ed sample in acid form as statedin 8.3.11. Report11.1 State that the specimens were tested as directed in TestMethod D 7131.11.2 Report the following information:11.2.1 The calculated IEC value (10.1) to the nearest0.0000X meg/g.12. Precision and Bias12.1 PrecisionThe precision of this test method i
26、s to beestablished on or before 2008.12.2 BiasThe procedure in this test method has no biasbecause the value of IEC can be defined only in terms of a testmethod.13. Keywords13.1 battery separator; grafted polyolefin material; ion ex-change capacity3Reagent Chemicals, American Chemical Society Specif
27、ications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convent
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31、ke your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D7131053
