1、Designation: D 4094 00Standard Test Method forAcid Content of Ethylene-Acrylic Acid Copolymers1This standard is issued under the fixed designation D 4094; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of the acidcontent of ethylene-acrylic acid (EAA) copolymers containing2.5 to 25 weight %
3、of acrylic acid.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parenthesis are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard
4、to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific hazardsstatements are given in Section 8.NOTE 1There is no similar or equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:D 1898 Practice for Sampling
5、 of Plastics2E 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods3E 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3IEEE/ASTM SI10 Standard for Use of the InternationalSystem of Units (SI): The Modern Metric System43. Terminology3
6、.1 Units and symbols used in this test method are thoserecommended in IEEE/ASTM SI10. Additional acronymsunique to this test method are defined in the text.4. Summary of Test Method4.1 In this test method, a weighed specimen is dissolved ina suitable hot solvent and titrated while hot with standard
7、baseto a visual equivalence point.5. Significance and Use5.1 EAAcopolymers possess unusual chemical and physicalproperties because they contain free acid groups. Since poly-mer performance in end-use applications is a function of theamount of copolymerized acrylic acid, it is important that acidcont
8、ents be determined quantitatively by a suitable method,such as that described herein.6. Apparatus6.1 Balance, analytical, accurate to 0.0001 g.6.2 Buret, 25-mL, 0.1-mL subdivisions, Class A, polytet-rafluoroethylene stopcock.6.3 Flask, Erlenmeyer, 250-mL, female standard-taper joint,with condenser,
9、reflux, matching male standard-taper joint.6.4 Stirrer/Hotplate, magnetic.6.5 Stirrer, magnetic.6.6 Stirring Bar, magnetic, 40 mm (1.5 in.) long,polytetrafluoroethylene-encased.7. Reagents and Materials7.1 Xylene, reagent-grade.7.2 n-Butanol, reagent-grade.7.3 Mixed SolventMix 3 volumes of xylene wi
10、th 1 vol-ume of n-butanol.7.4 Tetrabutylammonium Hydroxide (TBAH), solution inmethanol or benzene, in 1 M concentration.7.5 Standard Base (0.1 N)Mix 1 volume of 1 M TBAHsolution with 9 volumes of mixed solvent.7.6 Benzoic Acid, primary standard.7.7 Thymol Blue (TB) Indicator (Formula Weight of466.58
11、)Prepare 0.5 % solution by weighing 0.125 g ofreagent-grade TB (acid form) into a small beaker, adding 25mL of mixed solvent, and adding 0.268 milliequivalents of 0.1N base to form a clear, red-orange solution. Transfer to a glassdropping bottle.8. Hazards8.1 Solvents and titrants are malodorous and
12、 flammable andcan cause burns to skin, eyes, and lungs. Wear proper body andeye protection when handling these materials and conduct alloperations in a fume hood from which all possible sources ofignition have been removed.1This test method is under the jurisdiction of ASTM Committee D20 on Plastics
13、and is the direct responsibility of Subcommittee D20.70 on Analytical Methods(Section D20.70.11).Current edition approved Nov. 10, 2000. Published February 2001. Originallypublished as D 4094 82. Last previous edition D 4094 97.2Discontinued. See 1998 Annual Book of ASTM Standards , Vol 08.01.3Annua
14、l Book of ASTM Standards, Vol 14.02.4Annual Book of ASTM Standards, Vol 14.04.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.9. Sampling9.1 Analyze pelletized samples
15、 in the form as received.Analyze samples in duplicate.9.2 If the intent is to determine withinlot uniformity or todetermine the conformity of a lot to specification limits foraverage acid content, sample the lot in accordance withprinciples outlined in Practice D 1898.10. Standardization10.1 Weigh o
16、ut 0.2 to 0.3 g of benzoic acid and record itsweight to 0.0001 g. Transfer to a flask containing a stirring bar,add 100 mL of mixed solvent, and stir at room temperatureuntil dissolved.10.2 Add 6 drops of TB indicator and titrate with 0.1 NTBAH solution to the yellow-to-green-to-blue color change.Re
17、cord the titrant volume, V1, to 0.01 mL.10.3 Make a second standardization by repeating 10.1 and10.2.10.4 Determine a solvent blank by following 10.1 and 10.2except omit the benzoic acid. Record the value, V2, to 0.01 mL.10.5 Calculate titrant normality for each replicate determi-nation as follows:N
18、 5W/E!V1 V2!(1)where:N = normality, meq/mL,W = benzoic acid, g,V = titrant for benzoic acid, mL,V = titrant for blank, mL, andE = benzoic acid factor = 0.1221 g/meq.10.6 Average the two values for titrant normality and recordto 0.0001 meq/mL.10.7 Since solvent loss from titrant can occur readily,res
19、tandardize weekly.10.8 Whenever new batches of solvent are ready to use,redetermine the solvent blank.11. Conditioning11.1 Samples need not be conditioned.11.2 Conduct all titrations at the standard laboratory tem-perature of 23 6 2C (73.4 6 3.6F).12. Procedure12.1 Weigh out a specimen whose weight
20、is within 6 10 %of the applicable nominal weights given below and record to0.0001 g.Expected % Acid Specimen Weight, g88252.00.65NOTE 2Below 8 % acid, it may be possible to achieve greaterprecision and better-defined end points by using a specimen weighingmore than 2 g, provided the specimen dissolv
21、es completely and stays insolution during titration.NOTE 3At 8 % acid and above, increased precision can be achievedby adjusting specimen weight within the 0.65 to 2.0-g limits, according toexpected acid content.12.2 Transfer the weighed specimen to a flask containing astirring bar and add 100 mL of
22、 mixed solvent. Connect theflask to a condenser and begin stirring and rapid heating. Whenboiling begins, reduce the heat to produce a steady moderatestream of reflux from the condenser tip. Reflux until specimenis dissolved (for 30 min, or longer if necessary).12.3 Stop stirring and heating. Transf
23、er flask containingdissolved specimen to an unheated stirrer, begin stirring, add 6drops of TB indicator, and titrate while hot from a yellow colorthrough an intermediate green to a final blue color whichpersists for 30 s. Record the final titrant volume, V3, to 0.01mL.12.4 Analyze a second specimen
24、 by following 12.1-12.3above.13. Calculation13.1 Calculate acid content for each specimen as follows:A 5V3 V2! N! E!W3 100 (2)where:A = acid content as acrylic acid, weight %,N = titrant normality, meq/mL,W = specimen weight, g,V3= base for specimen, mL,V2= base for solvent blank, mL, andE = factor
25、for acrylic acid = 0.07206 g/meq.13.2 Average the two values for A, for reporting as theacrylic acid content of the sample.14. Report14.1 Sample identification.14.2 Acid content, as acrylic acid, weight %, to threesignificant figures.15. Precision and Bias515.1 Precision:15.1.1 Table 1 is based on a
26、 round-robin test conducted in2000, in accordance with Practice E 691, involving fourmaterials, tested by six laboratories, in the shortest possibletime, typically 1 to 2 days. Each test result is the average ofthree individual determinations. This study has been submittedto ASTM to be filed as a re
27、search report.15.1.2 The repeatability standard deviation and the repro-ducibility standard deviation are shown in Table 1.15.1.3 Sr, or the repeatability, is the within-laboratory stan-dard deviation of the average; r is 2.8 times Srand is the 95 %confidence level for the data. Repeatability is a m
28、easure of theprecision within-laboratory, obtained by a single operator usingthe same equipment to obtain the result on the same day.5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D20-1216 .TABLE 1 Acrylic Acid ContentMaterials
29、 Average SrSRrR6.6 % 6.6833 0.0370 0.0769 0.1035 0.21539.5 % 9.4467 0.1252 0.1477 0.3505 0.413620.1 % 20.2344 0.1044 0.3083 0.2923 0.863220.2 % 20.4150 0.1772 0.3549 0.4961 0.9937D409400215.1.4 SR, or the reproducibility, is the between-laboratorystandard deviation of the average; R is 2.8 times SRa
30、nd is the95 % confidence level for the data. Reproducibility is ameasure of the between-laboratory standard deviation obtainedby different operators on different equipment on different days.15.2 BiasNo information can be presented on the bias ofthis test method because no material having an accepted
31、reference value is available.16. Keywords16.1 acid content; ethylene-acrylic acid copolymers;titrationSUMMARY OF CHANGESThis section identifies the location of selected changes to this test method. For the convenience of the user,Committee D20 has highlighted those changes that may impact the use of
32、 this test Mmethod. This section mayalso include descriptions of the changes or reasons for the changes, or both.D 4094 97:(1) Added ISO equivalency statement.(2) Changed precision statement to reflect formation of a newtask group.D 4094 00:(1) Replaced Section 15, Precision and Bias, with new data
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34、h rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for addit
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36、 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).D4094003
