1、Designation: D 3566 03Standard Practice forRubberDetermination of Bromine in the Presence ofChlorine by Oxygen Combustion1This standard is issued under the fixed designation D 3566; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he 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 practice covers the determination of bromine andchlorine in rubber.1.2 This procedure is applicable t
3、o raw or cured NR, SBR,BR, IR, IIR, CIIR, BIIR, and EPDM rubbers and blends ofthese.1.3 Iodine interferes, but substances such as Zn2+,S,CN,and (CO3)2do not.1.4 The values stated in SI units are to be regarded as thestandard. The values in parentheses are for information only.1.5 This standard does
4、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 regulatory limitations prior to use. Specific safetyprecautions are given
5、in Section 7.2. Referenced Documents2.1 ASTM Standards:2E 200 Practice for Preparation, Standardization, and Stor-age of Standard and Reagent Solutions for ChemicalAnalysisE 443 Test Method for Sulfur in Organic Compounds byOxygen Flask Combustion33. Summary of Practice3.1 Samples of rubber, wrapped
6、 in filter paper, are burned inan oxygen combustion flask containing an aqueous solution ofhydrogen peroxide and sodium bisulfite. The carbon andhydrogen of the organic matter are oxidized. The combustedsolution is titrated directly for bromine and chlorine.4. Significance and Use4.1 This practice o
7、utlines a method for the determination ofbromine and chlorine, alone or together.4.2 CIIR and BIIR rubbers contain small amounts of chlo-rine and bromine and CR rubbers contain large amounts ofchlorine. For quality control and research and development, itis sometimes necessary to determine the amoun
8、t of thesehalogens in rubber. This practice can be used for thesepurposes.5. Apparatus5.1 Oxygen Combustion Flask (Schniger Flask)Achemical-resistant,4thick-walled oxygen combustion flask,51000 cm3, with JS35/25 ball-joint stopper, platinum samplecarrier, and pinch clamp.5.2 Infrared Safety Igniter,
9、5,6with cabinet and infrared light(an electrical igniter is also satisfactory).5.3 Magnetic Stirring Bar, covered with a chemical-resistant coating,5,7approximately 25 mm (1 in.) long, withouta spinning ring around the center.5.4 Magnetic Stirrer.5.5 Filter Paper, 30 by 30 mm, with a 35-mm extension
10、,black5,8for infrared or white5,9for electrical ignition.5.6 pH Meter,10equipped with a billet-type silver elec-trode11and a calomel electrode, in which the potassiumchloride solution has been replaced by a saturated potassiumnitrate solution, or equivalent automatic titrator.1This practice is under
11、 the jurisdiction of ASTM Committee D11 on Rubber andis the direct responsibility of Subcommittee D11.11 on Chemical Analysis.Current edition approved Nov. 1, 2003. Published December 2003. Originallyapproved in 1977. Last previous edition approved in 2001 as D 3566 96 (2001).2For referenced ASTM st
12、andards, 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 page onthe ASTM website.3Withdrawn.4Borosilicate glass has been found satisfactory.5The sole source of suppl
13、y of the apparatus known to the committee at this timeis A. H. Thomas Co., Philadelphia, PA, Catalog No. 6514-F20. If you are aware ofalternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsi
14、ble technical committee1, which you may attend.6The sole source of supply of the apparatus known to the committee at this timeis A. H. Thomas Co., Philadelphia, PA, Catalog No. 6516-G10.7Polytetrafluoroethylene has been found satisfactory.8The sole source of supply of the apparatus known to the comm
15、ittee at this timeis A. H. Thomas Co., Philadelphia, PA, Catalog No. 6514-F65.9The sole source of supply of the apparatus known to the committee at this timeis A. H. Thomas Co., Philadelphia, PA, Catalog No. 6513-C75.10A. Beckman pH meter Model SS-2 has been found satisfactory.1Copyright ASTM Intern
16、ational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Reagents6.1 Silver Nitrate Solution (0.001 M) must be freshly pre-pared. Pipet 10.0 cm3of standard120.1 M silver nitrate solutioninto a 1-dm3volumetric flask. Dilute to volume. Protect fromlight. Determin
17、e its molarity by titrating an accurately weighedsample of the reagent grade KCl or NaCl. Calculate themolarity as follows:Molarity 5 A 3 1000#/B 3 C! (1)where:A = grams of chloride weighed,B = molecular mass of chloride used, andC = titration volume, cm3.6.2 Sodium Bisulfite, 35 % in water,6.3 Hydr
18、ogen Peroxide, 3 % solution,6.4 Nitric Acid (6M).6.5 Aluminum Nitrate,6.6 Isopropyl Alcohol,6.7 Methyl Orange Indicator (1 % solution in methyl alco-hol), and6.8 Oxygen in Compressed Gas Cylinder.7. Safety Precautions7.1 The following safety precautions must be observed inthe combustion of rubber sa
19、mples:7.1.1 The flask shall not contain residues of organic solventsor vapor, which could cause an explosion. Any such solventsused for cleaning the flask should be rinsed out repeatedly withwater.7.1.2 The pressure generated by the rapid combustion couldcause the flask to explode. Therefore, combus
20、tion shall takeplace in a safety chamber with the door locked or behind asafety shield or hood shield (preferably in a safety chamber thatis behind a shield); the hands and face shall be withdrawnbehind a screen before the flame reaches the sample itself.Goggles or a face shield should be worn while
21、 observing thecombustion procedure.7.1.3 The flask should be left in the safety chamber until thelast spark is extinguished. At this point it is removed; but sincea slight vacuum is formed, goggles or a face shield should stillbe worn.8. Sampling8.1 The representative test portion selected for analy
22、sismust be milled or cut into very fine pieces before weighing.8.2 Due to the small sample size, the rubber and filter papershould be protected from contamination, and all operationsprior to combustion should be carried out while wearing plasticgloves.9. Procedure9.1 Place 10 cm3of water, five drops
23、 hydrogen peroxide,and2cm3of sodium bisulfite solution into the combustionflask.9.2 Fold the filter paper into a U-shaped sample boat.9.3 Weigh a sample of 80 to 100 mg (which should notexceed approximately 0.25 milliequivalents of bromine) to thenearest 0.1 mg. Place the sample into the folded filt
24、er paperboat.9.4 Place the folded paper firmly in the platinum samplecarrier hung on the hook of the stopper, with the pointed end ofthe paper projecting outward.9.5 Insert a tube from the oxygen cylinder close to thebottom of the flask and admit oxygen rapidly for five minutes.9.6 Carefully remove
25、the oxygen tube and stopper the flask.9.7 With the stopper upright, clamp the stopper tightly withthe pinch clamp.9.8 Place the flask in the infrared igniter chamber with thepointed end of the paper in line with the infrared beam andapproximately perpendicular to it. Close the door and turn onthe in
26、frared light (or electric igniter) until the paper ignites.9.9 After combustion is complete, moisten the stopperexternally with a few drops of water to avoid loss of halogen.Let sit 1 min. Shake the flask. Allow to rest for 30 min.9.10 Remove the pinch clamp, tilt the stopper to release thevacuum, a
27、nd open the flask.9.11 Where the bromine and chlorine content, or both, islow, repeat the procedure of 9.1 to 9.10, burning anothersample of about the same size over the same liquid.9.12 Open the flask; wash sides, stopper, and carrier withwater.9.13 Add 3.5 cm3of HNO3solution. Close flask and shake
28、to dissolve ash in basket.9.14 Pour solution into 400 cm3beaker containing a mag-netic stirrer.9.15 Wash the flask with isopropyl alcohol, adding wash-ings to beaker. The final composition should be close to 80 %alcohol, 20 % water.9.16 Add 4 g aluminum nitrate and two drops methylorange. Solution s
29、hould turn red. If not, add HNO3until redcolor appears.9.17 Titrate the solution with 0.001 M AgNO3(6.1), usingthe pH meter arrangement described (5.6) or an equivalentautomatic titrator. Add titrant in increments of 0.01 cm3.9.18 The first inflection point on the curve of millivoltsversus cubic cen
30、timetres of titrant, represents bromide; thesecond inflection point represents chloride. The end point is thepoint of maximum change in emf for an increment of titrant.9.19 For a better end point, a known amount of bromide andchloride may be added to the sample solution before titration.Deduct this
31、amount from the total titration.9.20 Carry a blank throughout the entire procedure, usingthe same quantity of reagents, but omitting the sample.10. Calculation10.1 Calculate the bromine content as follows:Bromine, % 5 B 2 A! 3 M 3 7.99/W (2)11Coleman Catalog No. 3-571 has been found satisfactory. An
32、y equivalent silverelectrode may be used. The electrode should not be coated by the user, especially forTest Method B. It may, however, be polished with a mild abrasive such as powderedkitchen cleanser, so that it is bright and shiny.12The 0.1 M silver nitrate solution should be prepared in accordan
33、ce withPractice E 200 or may be purchased.D3566032where:B = volume of AgNO3solution required for titration to thefirst inflection point, cm3,A = volume of AgNO3solution required for titration of theblank,M = molarity of the AgNO3solution, andW = mass of rubber samples burned in the flask, g.10.2 Cal
34、culate the chlorine content as follows:Chlorine, % 5 C 2 B! 3 M 3 3.55/W (3)where:C = volume of AgNO3solution required for titration to thesecond inflection point, cm3,B = volume of AgNO3solution required for titration to thefirst inflection point, cm3,M = molarity of the AgNO3solution, andW = mass
35、of rubber samples burned in the flask, g.11. Report11.1 Report the following information:11.1.1 Sample identification, and11.1.2 Test result, which is the average of two determina-tions.12. Precision and Bias12.1 This practice has not been tested in a round-robin testprogram.13. Keywords13.1 bromine
36、; chlorine; oxygen combustionASTM 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 rights, and the riskof inf
37、ringement 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 revision of this stand
38、ard 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 you shouldmake your vi
39、ews 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 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).D3566033
