1、Designation: D 5460 02 (Reapproved 2006)Standard Test Method forRubber Compounding MaterialsWater in RubberAdditives1This standard is issued under the fixed designation D 5460; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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 a procedure for the determina-tion of water in 2-mercaptobenzothiazole sulfenamide acce
3、l-erators by a Karl Fischer coulometric titration.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 concerns, if any, associated with its use. It is theresponsibi
4、lity 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., whi
5、ch 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 sulfenamide is heat
6、ed 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 thistwo-step procedure
7、automatically.4. Significance and Use4.1 This test method is designed to determine the watercontent of various rubber accelerators. Since2-mercaptobenzothiazole sulfenamide is hydrolytically un-stable, the residual water content is an important characteristic.5. Interferences5.1 The Karl Fischer tit
8、ration 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 prese
9、nt. 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 part of theirstructur
10、e 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. The evolved water is
11、 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 supplied by the m
12、anufac-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
13、the reagent system(s) recommendedby the manufacturer of the equipment to be used. The systemsmay be of the 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 Benz
14、oic Acid, reagent grade.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 Oct. 1, 2006. Published November 2006. Originallyapproved in 1993. Last previous edition approved i
15、n 2002 as D 5460 02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 maybe used. Pyridine-free s
16、olutions were used for the resultsreported in 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 confirmation of this is obtai
17、ned 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 available, canalso be used
18、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 least 300 g of water be detec
19、ted. 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:Vessel solution pyridine-conta
20、ining 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 noneDelay time operator choice9.3
21、 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 on the display at the co
22、mpletionof the process.9.5 Calculation:% Water 5 A 2 B!/C 3 100(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 individualanalysis to two decimal place
23、s 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(Nonmandatory Information)X
24、1. 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 instrument set-tings. Instrum
25、ent settings may be found in Table X1.1.X1.2 Since the addition of water to the sulfenamide, at acentral source and then sending this “wet” sample to theanalysts was not feasible, (unwanted degradation occurred), theparticipants were asked to analyze the sulfenamide initially forwater content, then
26、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.TABLE X1.1 Instruments UsedInstrument Mitsubishi PhotovoltOven temperature, C 125 110Vessel reagent pyridine free pyridine f
27、reeType solution single systemAdouble systemASample 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.D 5460 02 (2006)2ASTM International takes no posit
28、ion 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 their own responsibilit
29、y.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 should be addressed to ASTM
30、 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 Standards, at the address s
31、hown 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 610-832-9585 (phone), 610-8
32、32-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).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 0.75D 5460 02 (2006)3
