1、Designation: D5460 02 (Reapproved 2017)Standard Test Method forRubber Compounding MaterialsWater in RubberAdditives1This standard is issued under the fixed designation D5460; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 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 a procedure for the determina-tion of water in 2-mercaptobenzothiazole sulfenamide accel-e
3、rators by a Karl Fischer coulometric titration.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility
4、 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.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the D
5、ecision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Terminology2.1 Definitions:2.1.1 inert fillerany nonwater soluble additive used as asupport, binder, processing aid, d
6、edustant, etc., which may beused in the process of manufacture of a rubber additive.2.1.2 lota production quantity representative of a standardproduction unit.2.1.3 test portionthe actual material used in the analysis;it must be representative of the lot (see 2.1.2).3. Summary of Test Method3.1 The
7、sulfenamide is heated in an oven to remove water.This water is directed into the titration vessel of a Karl Fischercoulometric titrator with a stream of dry air or nitrogen. Thewater collected in the titration vessel is quantified coulometri-cally. Commercial instrumentation exists to carry out this
8、two-step procedure automatically.4. Significance and Use4.1 This test method is designed to determine the watercontent of various rubber accelerators. Since2-mercaptobenzothiazole sulfenamide is hydrolyticallyunstable, the residual water content is an important character-istic.5. Interferences5.1 Th
9、e Karl Fischer titration is inherently unreceptive tothe analysis of ketones, aldehydes, and amines. The reagentsystems of Section 7 can be used when free amines are presentif benzoic acid is added to the titration vessel before analysis.The acid serves to adjust the apparent pH difficulties when fr
10、eeamines are present. Add5gofbenzoic acid to the titrationvessel before starting a series of analyses. This is renewedwhenever a drift value exceeds 30 % of the microgram count orwhen a known amount of water does not produce the correctmicrograms count.5.2 Some rubber chemicals contain amines as par
11、t of theirstructure and may release these amines during the heatingprocess.6. Apparatus6.1 Karl Fischer Coulometric Apparatus, equipped with aheating oven to remove water from the test portion placed in it.The water is directed into the titration vessel by means of astream of dry air or nitrogen. Th
12、e evolved water is quantifiedcoulometrically. The instrument must satisfy conditions foundin 6.2 and Section 9.NOTE 1The apparatus must be used by those versed in its operation.It is not the intent or purpose of this test method to instruct the operator.This information is best obtained from manuals
13、 supplied by the manufac-turers.6.2 Sample Containers, capable of containing 1 to4gofatest portion.6.3 Balance, capable of weighing a test portion mass to60.1 mg.6.4 Syringes and Needles, to satisfy the requirements of 8.2.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberan
14、d Rubber-like Materials and is the direct responsibility of Subcommittee D11.11on Chemical Analysis.Current edition approved May 1, 2017. Published July 2017. Originally approvedin 1993. Last previous edition approved in 2012 as D5460 02 (2012). DOI:10.1520/D5460-02R17.Copyright ASTM International,
15、100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and
16、 Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.17. Reagents7.1 There are a wide variety of reagents on the market forcoulometric analysis. Use the reagent system(s) recommendedby the manufacturer of the equipment to be used. The systemsmay be of t
17、he one component type (same vessel and generatorsolutions) or the two component type (same solution for vesseland generator). Both systems were used in the results reportedin the Appendix.7.2 Benzoic Acid, reagent grade.7.3 De-Ionized Water and Commercial Water Standards.7.4 Nitrogen, Dry Air or Ine
18、rt Gas.7.5 Pyridine-Free or Pyridine-Containing Solutions may beused. Pyridine-free solutions were used for the results reportedin the Appendix.8. Calibration8.1 Karl Fischer coulometric analyzers need no calibration.Operation is based on Faradays Law which states that onecoulomb of electricity is n
19、eeded to electrolyze one mole of amaterial.8.2 Periodic confirmation of this is obtained by injecting aknown amount of water into the titration vessel. This mustproduce the theoretical g count within reasonable tolerances.As an example: Injection of 2.0 mm3of water should producea g count of 2000 g
20、6 50 to 100 g.8.3 Water standards, which are commercially available, canalso be used for 8.2. Follow the manufacturers instructions forusing these standards.9. Procedure9.1 Accurately weigh a well-mixed representative test por-tion to the nearest 0.1 mg and place it in the oven container.Sample mass
21、 will vary with water content. It is recommendedthat at least 300 g of water be detected. Follow manufactur-ers recommendations for appropriate sample mass and instru-ment settings and adjust sample mass accordingly.9.2 Appropriate titrator and oven settings follow. See theAppendix for the actual se
22、ttings used for this test method.Coulometer and Vessel:Vessel solution pyridine-containing or pyridine-freeGenerator solution pyridine-containing or pyridine-freeDrift correction onDelay noneVessel additive 5 g benzoic acidOven Conditions:Temperature operator choiceCarried gas nitrogen, dry air, or
23、inert gasCarrier gas flow operator choicePurge time noneDelay time operator choice9.3 Add benzoic acid to the titration vessel before beginningan analysis. Renew the acid whenever necessary, in accordancewith 7.1.9.4 Place the weighed test portion in the oven and start theanalysis. This will proceed
24、 automatically and produce a mi-crogram count of calculation on the display at the completionof the process.9.5 Calculation:% Water 5 A 2 B!/C 3100 (1)where:A = mass of water recovered from the test portion (mg),B = mass of water from a blank if needed (mg), andC = mass of test portion (mg).10. Repo
25、rt10.1 Report the percent water obtained from individualanalysis to two decimal places as described in this test method.11. Precision and Bias11.1 Precision and bias will be prepared when enough datais accumulated from co-operative studies.12. Keywords12.1 Karl Fischer coulometric titrator; rubber a
26、dditive;2-mercaptobenzothiazole sulfenamide; waterAPPENDIX(Nonmandatory Information)X1. LABORATORY STUDY OF 2-MERCAPTOBENZOTHIAZOLE SULFENAMIDEX1.1 For this co-operative study, one sample of2-mercaptobenzothiazole sulfenamide was divided and sent totwo laboratories. Analysis was completed with two d
27、ifferentinstruments with similar but slightly different instrument set-tings. Instrument settings may be found in Table X1.1.TABLE X1.1 Instruments UsedInstrument Mitsubishi PhotovoltOven temperature, C 125 110Vessel reagent pyridine free pyridine freeType solution single systemAdouble systemASample
28、 holder aluminum foil lined glass boats glass boatsDry nitrogen flow, cm3/min 100 250300ASingle SystemSame solution for vessel and generator.Double SystemDifferent solutions for vessel and generator.D5460 02 (2017)2X1.2 Since the addition of water to the sulfenamide, at acentral source and then send
29、ing this “wet” sample to theanalysts was not feasible, (unwanted degradation occurred), theparticipants were asked to analyze the sulfenamide initially forwater content, then add to this dried sample, a required quantityof water by means ofa5or10microliter syringe, to give a totalwater content of 0.
30、25 % and 0.75 %. Results may be found inTable X1.2.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 righ
31、ts, 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 withdrawn. Your comments are invited either for
32、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 your comments have not received a fair hearing
33、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 (single or multiple copies) of this standard may
34、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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ X1.2 Percentage of Water Recovered% Water Recovery Using This ProcedureMitsubishi PhotovoltOriginal SampleDay 1 0.06 0.06Day 1 0.06 0.05+ 0.25 % WaterDay 1 0.25 0.24Day 2 0.25 0.24+ 0.75 % WaterDay 1 0.74 0.77Day 2 0.76 0.75D5460 02 (2017)3
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