1、Designation: D5902 05 (Reapproved 2010)Standard Test Method forRubberDetermination of Residual Unsaturation inHydrogenated Nitrile Rubber (HNBR) by Iodine Value1This standard is issued under the fixed designation D5902; the number immediately following the designation indicates the year oforiginal a
2、doption or, in the case 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.1. Scope1.1 This test method covers the Wiijs procedure for thedetermination of u
3、nsaturation (iodine value) in hydrogenatednitrile rubbers.1.2 This test method is applicable only to those hydroge-nated nitrile rubbers derived from copolymers of acrylonitrileand butadiene.1.3 Iodine values are reported in centigrams of iodine pergram of HNBR cg(I2)/g. Higher iodine values indicat
4、e higherlevels of unsaturation.1.4 This test method is appropriate for calculating thepercent residual unsaturation of hydrogenated nitrile rubber ifthe iodine value of the base polymer before hydrogenation hasbeen determined.1.5 The values stated in SI units are to be regarded asstandard. No other
5、units of measurement are included in thisstandard.1.6 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 to establish appro-priate safety and health practices and determine the applica-bility of r
6、egulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1959 Test Method for Iodine Value of Drying Oils andFatty Acids3D4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3
7、. Summary of Test Method3.1 Asample of the raw, unvulcanized rubber is dissolved inchloroform.3.2 The dissolved sample is reacted with Wiijs solution.3.3 When the reaction is completed, potassium iodide solu-tion is added.3.4 The resultant solution is then back-titrated with sodiumthiosulfate soluti
8、on and the iodine value is calculated.4. Significance and Use4.1 Hydrogenated nitrile rubbers are available at differentlevels of unsaturation and different acrylonitrile content.Highly saturated grades offer optimum resistance to aging,such as exposure to heat, ozone and chemicals, and can becured
9、effectively only with peroxides or high energy radiation.4.2 Partially unsaturated grades can be cured by sulfursystems in addition to peroxides and high energy radiation.4.3 This test method provides a technique to determine theunsaturation level of hydrogenated nitrile rubbers in the raw,unvulcani
10、zed state. It can be used for research and develop-ment, quality control, and referee purposes.5. Apparatus5.1 Erlenmeyer Flasks, with ground glass stoppers (300mL).5.2 Flask Shaker.5.3 Pipets.5.4 Constant Temperature Bath.6. Reagents6.1 Reagent grade chemicals shall be used in all tests. Allreagent
11、s shall conform to the specifications of the Committeeon Analytical Reagents of the American Chemical Society.4Other grades may be used, provided it is first ascertained that1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D1
12、1.11 on Chemical Analysis.Current edition approved June 1, 2010. Published December 2010. Originallyapproved in 1996. Last previous edition approved in 2005 as D5902 051. DOI:10.1520/D5902-05R10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at
13、serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Reagent Chemicals, American Chemical Society Specifications, AmericanC
14、hemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), R
15、ockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto w
16、ater shall be understood to mean reagent water conformingto Type I of Specification D1193.6.3 Chloroform.6.4 Wiijs Solution (prepared in accordance with TestMethod D1959).6.5 Potassium Iodide Solution (prepared in accordancewith Test Method D1959).6.6 0.1 N Sodium Thiosulfate Solution (prepared in a
17、ccor-dance with Test Method D1959).6.7 Starch Indicator Solution (prepared in accordance withTest Method D1959).7. Procedure7.1 If the approximate level of unsaturation is known, thefollowing sample sizes are recommended:Approximate unsaturation level Sample weight in mg2 % 9309705 % 68072010 % 4304
18、70If the approximate level of unsaturation is unknown, asample weight of 680720 mg is recommended.7.2 Weigh the finely divided sample to the nearest 0.1 mg.Add the sample to a 300-mL glass stoppered Erlenmeyer flaskcontaining 50 mL of chloroform. Using the flask shaker, shakeuntil the samples are co
19、mpletely dissolved in the chloroform(approximately 1 h).7.3 Immediately place the flask containing the dissolvedsample into a constant temperature bath maintained at 23 6 1C for 30 min.7.4 Pipet 25 cm3of Wiijs solution into the flask containingthe specimen while shaking the flask. Replace the glass
20、stopperand return the flask to the constant temperature bath maintainedat 23 6 1Cfor2h.7.5 Remove the flask from the constant temperature bathand quickly add 10 cm3of potassium iodide solution whileshaking the flask vigorously.7.6 Wash off any iodine from the stopper into the flask withdistilled wat
21、er. Wait 5 min before beginning the titration.7.7 Titrate with the 0.1 N sodium thiosulfate solution,adding it gradually while shaking the flask vigorously. Con-tinue the titration until the yellow coloring is just about todisappear. Add 1 to 2 cm3of starch indicator solution andcontinue the titrati
22、on until the violet color just disappears.7.8 Allow the flask to stand for 30 min after the titration,then shake the flask, and if color returns, continue the titration.7.9 Run a blank determination following the titration stepsas described in 7.2 through 7.8 concurrently with the sampleunder test.8
23、. Calculation8.1 Calculate the iodine value as follows:Iodine value 50.1 3 f 3 B 2 A! 3 126.9 3 1001000 3 M50.1 3 f 3 B 2 A! 3 12.69M(1)where:f = normality factor of the 0.1 N sodium thiosulfatesolution,A =cm3of sodium thiosulfate solution required fortitration of the sample,B =cm3of sodium thiosulf
24、ate solution required fortitration of the blank,M = mass of the sample in grams,126.9 = atomic mass of iodine,1000 = conversion factor from the mg equivalent ofsodium thiosulfate to the g equivalent, and100 = conversion factor from g to cg.8.2 Calculate the percent of residual unsaturation if theiod
25、ine value of the base polymer prior to hydrogenation isknown, as follows:% Residual unsaturation5Iodine value measuredIodine value of the base polymer3 100(2)9. Report9.1 The report shall include the following information:9.1.1 Proper sample identification,9.1.2 Number of data points used to obtain
26、the result,9.1.3 The iodine value obtained, and9.1.4 The percent of residual unsaturation to the nearest0.1 %, if applicable.10. Precision and Bias510.1 This precision and bias section has been prepared inaccordance with Practice D4483. Refer to Practice D4483 forterminology and other statistical ca
27、lculation details.10.2 PrecisionThe precision results in this precision andbias section give an estimate of the precision of this testmethod with the materials (rubbers) used in the particularinterlaboratory program as described in 10.3 and 10.4. Theprecision parameters should not be used for accept
28、ance/rejection testing of any group of materials without documen-tation that they are applicable to those particular materials andthe specific testing protocols that include this test method.10.3 A Type I/Class II interlaboratory precision was evalu-ated. Both repeatability and reproducibility are s
29、hort term. Aperiod of one week separates replicate test results. Eachdetermination (measurement) is a test result.10.4 Three different materials (grades of hydrogenated ni-trile rubber) with different degrees of unsaturation were used inthe interlaboratory program. These materials were tested infour
30、 laboratories on two different days one week apart.Duplicate tests were run on each day. The analysis for precisionfollowed the general procedure as set forth in Annex ofPractice D4483. Each cell of Table A5.1 in Practice D4483contained four values (two test days, two results each day). Theestimates
31、 for repeatability parameters contain two undifferen-tiated sources of variation, replicates within days and betweendays. The final precision parameters are given in Table 1.5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D11-1
32、078.D5902 05 (2010)210.5 The precision of this test method may be expressed inthe format of the following statements that use what is calledan “appropriate value” of r, R,(r)or(R), that is, that valueobtained from Table 1 to be used in decisions about test resultsof this test method.10.6 Repeatabili
33、tyThe repeatability of this test methodhas been established as the appropriate value for any parameteras tabulated in Table 1. Two single test results obtained in thesame laboratory, under normal test method procedures, thatdiffer by more than this tabulated r must be considered asderived from diffe
34、rent or nonidentical sample populations.10.7 Reproducibility, R, of this test method has been estab-lished as the appropriate value for any parameter as tabulatedin Table 1. Two single test results obtained in two differentlaboratories, under normal test method procedures, that differby more than th
35、is tabulated R must be considered as derivedfrom different or nonidentical sample populations.10.8 Repeatability and reproducibility expressed as a per-centage of the mean level (r) and (R) have equivalent applica-tion statements as 10.6 and 10.7 for r and R. For the (r) and (R)statements the differ
36、ence in the two single test results isexpressed as a percentage of the arithmetic mean of the two testresults.10.9 BiasIn test method terminology, bias is the differ-ence between an average test value and the reference (or true)test property value. Reference values do not exist for this testmethod s
37、ince the value (of the test property) is exclusivelydefined by the test method. Bias, therefore, cannot be deter-mined.11. Keywords11.1 HNBR; iodine value; residual unsaturationASTM International takes no position respecting the validity of any patent rights asserted in connection with any item ment
38、ionedin 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 entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee
39、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 additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting
40、 of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake 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 B
41、ox 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). Per
42、mission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE 1 Type 1 PrecisionResidual Unsaturation of HNBR by Iodine ValueHNBRNominalContentACN,%Mean(cgI2/g)Within LaboratoryABetween LaboratoryASrr (r) SRR (R)#1 33 6.39 0.282 0.800 12.50 0.324
43、0.916 14.30#2 36 12.57 0.181 0.512 4.07 0.344 0.973 7.74#3 36 28.75 0.262 0.741 2.58 0.496 1.400 4.87ASymbols are defined as follows:Sr= within-laboratory standard deviation,r = repeatability, measurement units,(r) = repeatability, %SR= between-laboratory standard deviation,R = reproducibility, measurement units, and(R) = reproducibility,% .D5902 05 (2010)3
