1、Designation: D 1652 04Standard Test Method forEpoxy Content of Epoxy Resins1This standard is issued under the fixed designation D 1652; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenthe
2、ses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the procedure for manual andautomatic titratio
3、n of epoxy resins for the quantitative deter-mination of the percent epoxide content from 0.1 26 %epoxide.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concer
4、ns, if any, 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. For specific hazardstatements, see Section 6.2. Referenced Documents2.1 ASTM Standa
5、rds:2D 1193 Specification for Reagent Water2.2 Other Documents:OSHA Regulations, 29 CFR, paragraphs 1910.1000 and1910.120033. Summary of Test Method3.1 The resin is dissolved in a suitable solvent and theresulting solution is titrated with hydrogen bromide eitherdirectly or in situ. The hydrogen bro
6、mide reacts stoichiometri-cally with epoxy groups to form bromohydrins; therefore, thequantity of acid consumed is a measure of the epoxy content.3.1.1 In Test MethodA, the titration is direct with a standardsolution of hydrogen bromide in glacial acetic acid.3.1.2 In Test Method B, the titration is
7、 with standardperchloric acid in the presence of an excess of tetraethylam-monium bromide. Hydrogen bromide generated in situ by theaddition of perchloric acid to the quaternary ammonium haliderapidly opens the oxirane ring.3.1.3 In the Automatic Titration Method, the reaction ismeasuring the milivo
8、lt (MV) potential as perchloric acid isadded, which combines with the bromide to form the hydro-bromic acid, which reacts with the epoxide group. As thereaction progresses, the potential will gradually increase untilthe reaction nears completion at which point the potentialincreases very quickly. Th
9、e titrator measures the rate of thereaction by calculating the change in potential between per-chloric acid addition increments. When the change in potentialbegins to decrease, the titrator determines that the titration iscomplete. The epoxide content is calculated using the reagentfactor entered by
10、 the user during standardization, the weight ofthe sample, and the volume of perchloric acid added duringtitration.4. Significance and Use4.1 The epoxy content of epoxy resins is an importantvariable in determining their reactivity and the properties ofcoatings made from them. These test methods may
11、 be used todetermine the epoxy content of manufactured epoxy resins andconfirm the stated epoxy content of purchased epoxy resins.5. Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the speci
12、fications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5
13、.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type II of Specification D 1193.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct respon
14、sibility ofSubcommittee D01.33 on Polymers and Resins.Current edition approved November 1, 2004. Published December 2004.Originally approved in 1969. Last previous edition approved in 1997 asD 1652 97.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Servi
15、ce at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.4Reagent Chemicals, Ame
16、rican Chemical Society Specifications, 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 Formular
17、y, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.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.6. Hazards6.1 Hydrogen bromide and glacial acetic acid are
18、corrosive.Chlorobenzene and chloroform are considered hazardous. Inaddition to other precautions, take care to avoid inhalation andskin or eye contact with these chemicals. Use goggles or a faceshield, or both. Protect skin by use of suitable protectiveclothing. All specimen preparations shall be do
19、ne in a wellventilated area, such as a fume hood.6.2 Consult current OSHA regulations, suppliers MaterialSafety Data Sheets, and local regulations for all materials usedin this test method.Manual Titration for Epoxy Content of Epoxy Resins7. Apparatus7.1 Buret, closed-reservoir type, bottom filling,
20、 25-mL with110-mL division, or potentiometric automatic titrator.7.2 Erlenmeyer Flasks, 100-mL, 250-mL, and 500-mL.7.3 Magnetic Stirrer, adjustable speed.7.4 Magnetic Stirring Bars, polytetrafluoroethylene (PTFE)coated.7.5 Pipets:7.5.1 Measuring Pipet, 25-mL.7.5.2 Volumetric Pipet, 50-mL.7.6 Volumet
21、ric Flask,1L.7.7 Bottle, 2 oz wide-mouth, or 100-mL disposable beaker,or equivalent.8. Reagents8.1 Glacial Acetic Acid (WarningSee Section 6).8.2 Tetraethylammonium Bromide, anhydrous crystals.8.3 Perchloric Acid (HClO4), 60 % (WarningSee Sec-tion 6).8.4 Acetic Anhydride (WarningSee Section 6).8.5 M
22、ethylene Chloride (WarningSee Section 6).8.6 Crystal Violet Indicator, crystals.8.7 Potassium Acid Phthalate(KHC8H4O4) primary stan-dard grade.9. Reagent Preparation9.1 Perchloric Acid (0.1 N Solution in Glacial AceticAcid) (WarningSee Section 6)Prepare in the followingmanner and sequence in order t
23、o avoid an excessive rise intemperature.9.1.1 Place approximately 250 mL of glacial acetic acid intoa 1 L volumetric flask. Add 13 mL of 60 % perchloric acid andmix. Add 50 mL of acetic anhydride, dilute to the mark withglacial acetic acid, and mix thoroughly.9.1.2 Allow to stand at least 8 h for co
24、mpletion of reactionbetween the acetic anhydride and water. A shorter time periodmay be used if completion of the reaction is analyticallyverified.9.2 Tetraethylammonium Bromide Solution in Glacial Ace-tic Acid (WarningSee Section 6):9.2.1 Dissolve, with agitation at room temperature, 100 g oftetrae
25、thylammonium bromide in 400 mL of glacial acetic acid.9.3 Crystal Violet Indicator SolutionPrepare 0.1 % solu-tion of crystal violet indicator in glacial acetic acid(WarningsSee Section 6).10. Standardization of 0.1 N Perchloric Acid Reagent10.1 Standardization with Potassium Acid Phthalate:10.1.1 D
26、issolve 0.4 g of potassium acid phthalate, weighedaccurately to the nearest milligram, in 50 mL of glacial aceticacid, and add 6 to 8 drops of crystal violet indicator solution.Insert a clean stirring bar into the sample, and adjust themagnetic stirrer to effect solution. Continue agitation through-
27、out the titration procedure. Titrate with perchloric acid reagentsolution to the end point, which is a sharp change in color fromblue to green, stabilize for at least 2 min.10.1.2 Calculate and record the perchloric acid reagentnormality as follows:N 5 W 3 1000!/204.23 V! (1)where:N = normality of p
28、erchloric acid reagent,W = potassium acid phthalate used, g, andV = volume of perchloric acid reagent required to titratethe standard, mL.10.2 Standardization with Potassium Hydrogen Phthalate:10.2.1 Dissolve 0.25 to 0.40 g of the potassium hydrogenphthalate accurately weighed to the nearest milligr
29、am into a 2oz wide-mouth bottle or 100 mL disposable beaker. Add 40 to50 mL of glacial acetic acid. Insert a clean stirring bar into thesample and adjust the magnetic stirrer to effect solution.Continue agitation throughout the titration procedure.10.2.2 Add 10 mL of tetraethylammonium bromide reage
30、ntand 6 to 8 drops of crystal violet indicator solution and titrateto a sharp blue-to-green end point with the perchloric acidreagent solution. The end point should be stable for at least 30s.10.2.3 Calculate and record the perchloric acid reagentfactor, F, as follows:F 5 Wd3 E!/V (2)where:Wd= potas
31、sium hydrogen phthalate standard used, g andE = epoxide of the potassium hydrogen phthalate stan-dard used (normally 21.05), weight %.11. Procedure11.1 Weigh the required amount of specimen into a 2-ozdisposable glass bottle or plastic beaker. The amount ofspecimen weight used is dependent on the ex
32、pected epoxideequivalent weight (EEW) as follows:D1652042EEW Approximate Specimen Size, g170375 0.4375600 0.66001000 0.810001500 1.315002000 1.820002500 2.325005000 2.811.2 Add 10 to 15 mL of methylene chloride to thespecimen. Insert a clean stirring bar and adjust the magneticstirrer to effect solu
33、tion. Continue agitation through the titra-tion procedure.11.3 Add 10 mL of tetraethylammonium bromide reagentand 6 to 8 drops of crystal violet indicator solution. Titrate with0.1 N perchloric acid reagent to a sharp blue to green end pointwhich is stable for at least 30 s. Record the volume ofperc
34、hloric acid reagent used to titrate the specimen.12. Calculation12.1 If 10.1 (Standardization of Potassium Acid Phthalate)is used for standardization, calculate weight percent epoxide,E, as follows:E 5 4.3 3 V 3 N/W (3)12.2 If 10.2 (Standardization of Potassium Acid Phthalate)is used for standardiza
35、tion, calculate the weight percent ep-oxide, E, as follows:E 5 F 3 V/We(4)where:We= weight of epoxy resin specimen used, g.12.3 Calculate the epoxy equivalent weight, WEEW,asfollows:WEEW5 43 3 100/E (5)where 43 = mol weight of the epoxy ring.12.4 Calculate weight percent of oxirane oxygen, O,asfollo
36、ws:O 5 16/43 3 E 5 1.6 3 V 3 N/W (6)13. Precision13.1 A liquid epoxy resin sample with approximately24.1 % epoxide was tested by seven laboratories where tenanalysts obtained the following results:13.1.1 RepeatabilityThe difference between two resultsobtained by the same analyst should not vary by m
37、ore than1.22 % relative.13.1.2 ReproducibilityThe difference between two re-sults, each the mean of two determinations obtained byanalysts in different laboratories should not vary by more than2.97 % relative.Automatic Titration Method14. Apparatus14.1 Automatic Titrator, equipped with a 10 mL buret
38、te anda pH electrode.14.2 A Four Place Analytical Balance.15. Reagents and Materials15.1 Perchloric Acid, 0.1N in glacial acetic acid.15.2 Tetramethyl Ammonium Bromide (TEAB), solution inglacial acetic acid.15.3 Methylene Chloride (MECL).15.4 Potassium Hydrogen Phthalate (KHP).16. Reagent Preparatio
39、n16.1 Perchloric Acid (0.1 N Solution in Glacial AceticAcid) (WarningSee Section 6.)Prepare in the followingmanner and sequence in order to avoid an excessive rise intemperature.16.1.1 Place approximately 250 mL of glacial acetic acidintoa1Lvolumetric flask. Add 13 mL of 60 % perchloric acidand mix.
40、 Add 50 mL of acetic anhydride, dilute to the markwith glacial acetic acid, and mix thoroughly.16.1.2 Allow to stand at least 8 h for completion of reactionbetween the acetic anhydride and water. A shorter time periodmay be used if completion of the reaction is analyticallyverified.16.2 Tetraethylam
41、monium Bromide Solution in Glacial Ace-tic Acid (WarningSee Section 6):16.2.1 Dissolve, with agitation at room temperature, 100 gof tetraethylammonium bromide in 400 mL of glacial aceticacid.17. Standardization of 0.1 N Perchloric Acid Reagent17.1 Standardization with Potassium Acid Phthalate:17.1.1
42、 Dissolve 0.25 g of potassium acid phthalate, weighedaccurately to the nearest milligram, in 50 mL of glacial aceticacid, and 15 mL 20 % TEAB solution. Titrate with perchloricacid reagent solution.17.1.2 Calculate and record the perchloric acid reagentnormality as follows:N 5 W 3 1000!/204.2 3 V! (7
43、)where:N = normality of perchloric acid reagent,W = potassium acid phthalate used, g, andV = volume of perchloric acid reagent required to titratethe standard, mL.18. Procedure18.1 Fill burette with 0.1 N perchloric acid solution inglacial acetic acid.18.2 Flush all titrator lines to assure no air b
44、ubbles arepresent.18.3 Add the appropriate amount of sample to a sample cup.18.4 Add 30 mL of MECL and 15 mL of TEAB to thesample.18.5 Select the correct method on the titrator and run thesample. The method should prompt when to enter the sampleweight.18.6 The titrator will automatically print out t
45、he resultsusing the formula in Section 19.19. Titration Calculation19.1 Calculate:R2 5 R 3 C 3 0.1000/M (8)D1652043where:R2 = epoxide content,R = actual mL perchloric acid used to reach equivalencepoint,C = constant of 4.3 (see Note 2), andM = weight of the sample used.NOTE 10.1000 is the normality
46、of the perchloric acid.NOTE 24.3 is the theoretical molecular weight of the epoxide ring, 43,and it is adjusted to 4.3 for the calculation to percent epoxide.20. Precision20.1 An epoxy resin sample, with 5.74 % epoxide, wastested by six laboratories in five different countries for %epoxide content a
47、nd the following results were obtained:20.1.1 RepeatabilityThe difference between two resultsobtained by the same analyst should not vary by more than1.1 % relative.20.1.2 ReproducibilityThe difference between laborato-ries should no vary by more than 0.8 % relative.21. Keywords21.1 epoxide equivale
48、nt weight (EEW); liquid epoxy resin;oxirane; weight percent epoxide; weight per epoxy equivalent(WPE)SUMMARY OF CHANGESCommittee D01 has identified the location of selected changes to this standard since the last issue(D 1652 - 97) that may impact the use of this standard.(1) The range of this stand
49、ard was entered into the Scopesection.(2) Test Method A was deleted.(3) Test Method B was renamed Manual Titration Method.(4) Manual Titration Method corrected the Potassium Hy-drogen Phthalate Standard number.(5) Automatic Titration Method was added.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are
