1、Designation: D5460 02 (Reapproved 2012)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.2. Terminology2.1 Definitions:2.1.1 inert fillerany nonwater soluble additive used as asupport, binder, processing aid, dedustant, etc., which m
5、ay 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 sulfenamide is heated i
6、n 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 thistwo-step procedure auto
7、matically.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 The Karl Fischer titratio
8、n 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 freeamines are present. A
9、dd5gofbenzoic 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 part of theirstructure and
10、 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. The evolved water is quan
11、tifiedcoulometrically. 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 supplied by the manufa
12、c-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 8.2.7. Reagents7.1 There are a wide variety of reagents on the market forcoulometric analysis. Use the r
13、eagent system(s) recommendedby the manufacturer of the equipment to be used. The systemsmay be of the one component type (same vessel and generator1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.11 on Chemical Analysis.C
14、urrent edition approved Aug. 1, 2012. Published November 2012. Originallyapproved in 1993. Last previous edition approved in 2006 as D5460 02 (2006).DOI: 10.1520/D5460-02R12.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1solutions) o
15、r 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 Inert Gas.7.5 Pyridine-Free or Pyridine-Containing Solutions ma
16、y 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 needed to electrolyze one mole of amaterial.8.2 Periodic conf
17、irmation 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 6 50 to 100 g.8.3 Water standards, which are commercially av
18、ailable, 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 will vary with water content. It is recommendedthat at leas
19、t 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 settings used for this test method.Coulometer and Vessel:Vesse
20、l 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 inert gasCarrier gas flow operator choicePurge time noneDela
21、y 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 automatically and produce a mi-crogram count of calculation
22、 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. Report10.1 Report the percent water obtained from individualanal
23、ysis 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 additive;2-mercaptobenzothiazole sulfenamide; waterAPPENDIX(N
24、onmandatory 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 differentinstruments with similar but slightly different inst
25、rument 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 holder aluminum foil lined glass boats glass boatsDry nitro
26、gen flow, cm3/min 100 250300ASingle SystemSame solution for vessel and generator.Double SystemDifferent solutions for vessel and generator.D5460 02 (2012)2X1.2 Since the addition of water to the sulfenamide, at acentral source and then sending this “wet” sample to theanalysts was not feasible, (unwa
27、nted 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 0.25 % and 0.75 %. Results may be found inTable X1.2.ASTM Inte
28、rnational 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 entirely
29、 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 additional standardsand sho
30、uld 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 you shouldmake your views known to the ASTM Committee on Sta
31、ndards, 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
32、-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 ASTM website (www.astm.org/COPYRIGHT/).TABLE 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 (2012)3
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