1、Designation: D 5902 05Standard Test Method forRubberDetermination of Residual Unsaturation inHydrogenated Nitrile Rubber (HNBR) by Iodine Value1This standard is issued under the fixed designation D 5902; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he 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 covers the Wiijs procedure for thedetermination of unsaturation (io
3、dine 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 indicate higherlevels
4、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 This standard does not purport to address all of thesafety concerns, if any, associat
5、ed 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 1193 Specification for Reagent WaterD 1959 Test Method for
6、Iodine Value of Drying Oils andFatty AcidsD 4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3. Summary of Test Method3.1 Asample of the raw, unvulcanized rubber is dissolved inchloroform.3.2 The dissolved sample is reacted with Wi
7、ijs 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 solution and the iodine value is calculated.4. Significance and Use4.1 Hydrogenated nitrile rubbers are available at differentlevels of unsatur
8、ation and different acrylonitrile content.Highly saturated grades offer optimum resistance to aging,such as exposure to heat, ozone and chemicals, and can becured effectively only with peroxides or high energy radiation.4.2 Partially unsaturated grades can be cured by sulfursystems in addition to pe
9、roxides and high energy radiation.4.3 This test method provides a technique to determine theunsaturation level of hydrogenated nitrile rubbers in the raw,unvulcanized state. It can be used for research and develop-ment, quality control, and referee purposes.5. Apparatus5.1 Erlenmeyer Flasks, with gr
10、ound 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. Allreagents shall conform to the specifications of the Committeeon Analytical Reagents of the American Chemical Society.3Other grades may be used,
11、provided it is first ascertained thatthe reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Type I of Specification D 1193
12、.6.3 Chloroform.6.4 Wiijs Solution (prepared in accordance with TestMethod D 1959).1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.11 on Chemical Analysis.Current edition approved Dec. 1, 2005. Published January 2006. Or
13、iginallyapproved in 1996. Last previous edition approved in 2001 as D 5902 96 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary
14、page onthe ASTM website.3Reagent Chemicals, American 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
15、United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.5 Potassium Iodide Solution (prepared in accordancewith Test Method D 1959).
16、6.6 0.1 N Sodium Thiosulfate Solution (prepared in accor-dance with Test Method D 1959).6.7 Starch Indicator Solution (prepared in accordance withTest Method D 1959).7. Procedure7.1 If the approximate level of unsaturation is known, thefollowing sample sizes are recommended:Approximate unsaturation
17、level Sample weight in mg2 % 9309705 % 68072010 % 430470If 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.
18、 Using the flask shaker, shakeuntil the samples are completely dissolved in the chloroform(approximately 1 h).7.3 Immediately place the flask containing the dissolvedsample into a constant temperature bath maintained at 23 61C for 30 min.7.4 Pipet 25 cm3of Wiijs solution into the flask containingthe
19、 specimen while shaking the flask. Replace the glass stopperand return the flask to the constant temperature bath maintainedat 23 6 1C for 2 h.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
20、iodine from the stopper into the flask withdistilled water. 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
21、 cm3of starch indicator solution andcontinue the titration 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
22、7.2 through 7.8 concurrently with the sampleunder test.8. 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 requ
23、ired fortitration of the sample,B =cm3of sodium thiosulfate 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
24、Calculate the percent of residual unsaturation if theiodine 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 id
25、entification,9.1.2 Number of data points used to obtain 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 Bias10.1 This precision and bias section has been prepared inaccordance with Practice D 4483. Refer t
26、o Practice D 4483 forterminology and other statistical calculation 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
27、.4. Theprecision parameters should not be used for acceptance/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
28、 evalu-ated. Both repeatability and reproducibility are short 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 in
29、terlaboratory program. These materials were tested infour 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 D 4483. Each cell of Table A5.1 in Practice D 4483contained four
30、 values (two test days, two results each day). Theestimates for repeatability parameters contain two undifferen-tiated sources of variation, replicates within days and betweendays. The final precision parameters are given in Table 1.10.5 The precision of this test method may be expressed inthe forma
31、t 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 RepeatabilityThe repeatability of this test methodhas been established as the appropriate value fo
32、r any parameteras tabulated in Table 1. Two single test results obtained in thesame laboratory, under normal test method procedures, thatD5902052differ by more than this tabulated r must be considered asderived from different or nonidentical sample populations.10.7 Reproducibility, R, of this test m
33、ethod 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 this tabulated R must be considered as derivedfrom different or nonidentical samp
34、le 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 difference in the two single test results isexpressed as a percentage of the arithmet
35、ic 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 since the value (of the test property) is exclusivelydefined by the test method.
36、 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 mentionedin this standard. Users of this standard are expressly advised that determ
37、ination 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 and must be reviewed every five years andif not revised, either reapproved or w
38、ithdrawn. 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 of theresponsible technical committee, which you may attend. If you feel that
39、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 Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (s
40、ingle 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).TABLE 1 Type 1 PrecisionResidual Unsaturation of HNBR by Iodine ValueHNBRNominalCon
41、tentACN,%Mean(cgI2/g)Within LaboratoryABetween LaboratoryASrr (r) SRR (R)#1 33 6.39 0.282 0.800 12.50 0.324 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,% .D5902053
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