1、Designation: D4004 06 (Reapproved 2012)Standard Test Methods forRubberDetermination of Metal Content by Flame AtomicAbsorption (AAS) Analysis1This standard is issued under the fixed designation D4004; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、case of revision, the year 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 These t
3、est methods cover the determination of lead,zinc, copper, and manganese in raw rubber and rubber com-pounds, vulcanized or unvulcanized. The level at which themetals are present is taken into account by suitable adjustmentsof sample mass and dilution.1.2 Certain compounding ingredients, present in t
4、he rubbersample will dictate which of the methods should be used. Referto Section 3. Five methods of determination are as follows:SectionsMethod A 8Method B 9Method C 10Method D 14-22Method E 23-311.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are incl
5、uded in thisstandard.1.4 This standard does 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 t
6、o use.2. Referenced Documents2.1 ASTM Standards:2D1076 Specification for RubberConcentrated, AmmoniaPreserved, Creamed, and Centrifuged Natural LatexD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustriesE663 Practice for Flame Atomic A
7、bsorption Analysis32.2 ISO Standards:ISO 1396 RubberCopper ContentPhotometric Technique-Determination4ISO 1655 RubberManganese ContentPhotometric Tech-niqueDetermination43. Summary of Test Methods3.1 Method ADetermination of lead and zinc in rubber notcontaining any halogen; in the case of lead, als
8、o not containingany silica filler. See Section 8.3.1.1 In Method A, the rubber is furnace-dried in a platinumcrucible at 250C, followed by furnace ashing for 1 to2hat550C. The ash is dissolved with the aid of concentratedhydrochloric acid (HCl) and the resulting solution suitablydiluted for Atomic A
9、bsorption Spectrometric (AAS) determi-nation of the lead and zinc.3.2 Method BDetermination of lead and zinc in rubbercontaining silica filler, but no halogen. See Section 9.3.2.1 In Method B the rubber is ashed in platinum as inMethod A. The ash is then fused with a lithium or sodiumtetraborate or
10、metaborate flux, after which the fused mixture isdissolved with the aid of HCl for subsequent AAS analysis.3.3 Method CDetermination of lead and zinc in rubbercontaining halogen. See Section 10.3.3.1 In Method C the rubber is wet-ashed with the aid ofconcentrated sulfuric acid (H2SO4) and nitric aci
11、d (HNO3),evaporated to dryness, and further ashed in a muffle furnace at550C, after which the ash is dissolved as in Method A forsubsequent AAS analysis.3.4 Method DDetermination of copper in raw rubber andrubber latex, both synthetic and natural (see 14.2).3.4.1 In Method D the rubber is ashed at 5
12、50C, the ash isthen digested in hydrochloric acid, and copper is determined byAAS analysis.3.5 Method EDetermination of manganese in raw naturalrubber and rubber latex, both synthetic and natural (see 23.2).3.5.1 In Method E the rubber is ashed at 550C, the ash isdigested in hydrochloric acid and th
13、e manganese is determinedby AAS analysis.1These test methods are under the jurisdiction of ASTM Committee D11 onRubber and are the direct responsibility of Subcommittee D11.11 on ChemicalAnalysis.Current edition approved May 1, 2012. Published May 2012. Originallyapproved in 1981. Last previous edit
14、ion approved in 2006 as D4004 06. DOI:10.1520/D4004-06R12.2For 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 page onthe ASTM website.3Wi
15、thdrawn.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.5.2 See 3.6.3.6 Because this standard does not contain procedures fo
16、roptimizing instrument performance, nor does it instruct theanalyst in the basics of flame atomic absorption, it is recom-mended that the references found in Section 2 be studied forthese purposes.4. Significance and Use4.1 These test methods are suitable for process control, forproduct acceptance,
17、and for research and development.5. Apparatus5.1 Laboratory Balance.5.2 Laboratory Muffle Furnace.5.3 Hot Plate.5.4 Platinum Crucibles,25cm3content minimum.5.5 Common Borosilicate Glassware.5.6 Meker Burner.5.7 Atomic Absorption Spectrophotometer, operated in ac-cordance with the manufacturers direc
18、tions for optimuminstrument performance.6. ReagentsNOTE 1Observe all recognized health and safety precautions whilecarrying out this procedure.6.1 All reagents used shall be of analytical grade anddistilled de-ionized water (DDW) shall be used for anydilutions.6.2 Hydrochloric Acid (HCl) (density 1.
19、19 Mg/m3).6.3 Hydrochloric Acid (6 M)Dilute concentrated HClwith an equal volume of water.6.4 Lithium Carbonate (Li2CO3).6.5 Lithium Metaborate (LiBO2).6.6 Lithium Tetraborate (Li2B4O7).6.7 Nitric Acid (HNO3) (density 1.42 Mg/m3).6.8 Sodium Carbonate (Na2CO3).6.9 Sodium Tetraborate (Na2B4O710 H2O).6
20、.10 Sulfuric Acid (H2SO4) (density 1.83 Mg/m3).7. Sampling7.1 Selection of a test portion shall be at the discretion of theanalyst and shall be as representative of the sample as possible.METHOD A8. Procedure8.1 Weigh 0.1 g of dry rubber into a platinum 25-cm3or50-cm3crucible if lead and zinc are pr
21、esent at levels higherthan 0.5 %. Weigh a larger amount (up to 10 g) when the leadand zinc levels are lower. Record the mass of rubber, W,tothenearest 0.1 mg.8.2 Place the test portion in the muffle furnace at 250C for0.5 h. Raise the temperature to 550C for 1 h. If not completelyashed, continue ash
22、ing for another hour or two.8.3 Cool the crucible to room temperature and add 5 cm3of6 M HCl. Heat on a hot plate until the ash is completelydissolved and transfer quantitatively to a 25-cm3volumetricflask. Fill to the mark with DDW. For lead levels less than 10mg/kg (g/g) dissolve the ash in 2 cm3o
23、f 6 M HCl and transferto a 10-cm3volumetric flask.8.4 Determine the lead and zinc by AAS following PracticeE663. Keep the matrix of the blank, of the standard, and of thesample solutions as identical as possible. Any necessarydilutions of the sample solution are carried out with DDW.METHOD B9. Proce
24、dure9.1 Ash in platinum crucibles as described under 8.1 and 8.2using1gofrubber.9.2 To the ash obtained, add1gofa3-to-1 mixture ofsodium carbonate (Na2CO3) and sodium tetraborate(Na2B4O710 H2O) and mix the compounds using a cleanquartz or platinum rod. Fuse the mixture for a few minutes overa Meker
25、burner. Using platinum-tipped tongs, turn the crucible,so that all of the mixture fuses properly.NOTE 2Alternative fusing agents are a 3-to-1 mix of lithium carbon-ate (Li2CO3) and lithium tetraborate (Li2B4O7), and lithium metaborate(LiBO2) which, in that order, fuse at somewhat higher temperatures
26、.9.3 Cool to room temperature and dissolve the fused masswith 5 cm3of 6 M HCl. Magnetic stirring will speed up thedissolution. If necessary, add 5 to 10 cm3of DDW to aidsolution.9.4 Transfer the solution quantitatively to a 25-cm3volu-metric flask. Fill to the mark with DDW.9.5 Continue as set out i
27、n 8.4.METHOD C10. Procedure10.1 Weigh1gofrubber in the form of small pieces in aplatinum crucible or borosilicate beaker.10.2 Add 25 cm3of concentrated H2SO4and heat on a hotplate until the rubber is disintegrated (approximately 0.5 to1 h).10.3 Cool to room temperature and add dropwise 10 cm3ofconce
28、ntrated HNO3.10.4 Heat on a hot plate until the solution has become clear(approximately 1 to 3 h). Then evaporate to dryness and ash theresidue in a muffle furnace at 550C.10.5 Continue as set out in 8.3 and 8.4.11. Test Report11.1 The report shall include the following:11.1.1 The amount of lead and
29、 zinc found in the rubber totwo significant figures either in percent or mg/kg (ppm),11.1.2 The test method used,11.1.3 Graph of absorbances versus concentrations for thelead and zinc standards,11.1.4 Absorbances measured on the sample test solutions,11.1.5 A listing of instrumental conditions such
30、as lampcurrent, wavelength of the analytical line, type of flame, andtype of burner,11.1.6 Calculation of the lead and zinc concentrations in theoriginal rubber, and11.1.7 Notes on any unusual observations both with respectto the chemical procedure and the instrumental determination.D4004 06 (2012)2
31、12. Limits of Detection12.1 The limits of detection with acceptable error for aminimum absorbance of 0.050 are listed as a function ofsample mass and final dilution volume. See Table 1.13. Precision and Bias513.1 These precision statements have been prepared inaccordance with Practice D4483. Please
32、refer to this practicefor terminology and other testing and statistical conceptexplanations.13.2 Precision data obtained at the 3 % Zn and 1 % Pb levelare as follows:13.2.1 Zinc PrecisionThe Type 1 precision is estimatedfrom an interlaboratory study by six laboratories testing threematerials on thre
33、e days. A test result is the average of duplicatedeterminations.13.2.1.1 The Type 1 precision is expressed in absolute termsas percentage points. See Table 2.13.3 Lead PrecisionThe Type 1 precision is estimatedfrom an interlaboratory study by six laboratories testing threematerials on three days. A
34、test result is the average of duplicatedeterminations.13.3.1 The Type 1 precision is expressed in absolute termsas percentage points. See Table 3.13.4 Precision data obtained at the mg/kg (ppm) level are asfollows:13.4.1 Zinc Precision:The Type 1 precision is estimated from an interlaboratorystudy b
35、y five laboratories testing three materials on three days.A test result is the average of duplicate determinations (seeTable 4).13.4.1.1 Concentrations less than 1 mg/kg (ppm) cannot beprecisely determined by this test method.13.4.2 Lead Precision:The Type 1 precision is estimated from an interlabor
36、atorystudy by five laboratories testing two samples on three days. Atest result is an average of duplicate determinations (see Table5).13.4.2.1 Concentrations less than 1 mg/kg (ppm) cannot beprecisely measured by this test method.13.5 See also Section 31 for additional discussion of preci-sion.METH
37、OD D14. Significance and Use14.1 See 4.1.14.2 Copper in certain forms is known to catalyze theoxidative breakdown of natural rubber although the mechanismby which degradation is brought about is not fully understood.It is recognized that other forms of copper can be present in therubber even in rela
38、tively large amounts without degradationtaking place, but in these cases there is always the possibilitythat under the influence of some chemicals, notably theunsaturated acids, the copper could assume a more aggressiverole when the rubber is compounded.14.3 It would be advantageous to be able to an
39、alyticallydistinguish between catalytically active and inactive forms ofcopper but no generally accepted method has yet been putforward to doing so. There is no alternative therefore, but todetermine the total amount of copper in the rubber.14.4 Little is known concerning the influence of copper ont
40、he catalytic oxidation of synthetic rubbers, although it is5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D-11-1020.TABLE 1 Limits of DetectionAMethod A Method B Method CSample mass (g) 10 1 1Total volume (cm3)1 0 0Zinc 0.1 2.
41、5 1.0Lead 1.0 25.0 1.0AThe limits of detection for Method C can only be realized if extremely pureacids are used for the digestion. With the usual reagent grade acids, even when acorrection is applied on the basis of a blank digestion, the limit of determination islikely a factor of ten to one hundr
42、ed higher.TABLE 2 Type 1 PrecisionZinc (Normal Level)NOTESr = repeatability standard deviation, in measurement units.r = repeatability, in measurement units.(r) = repeatability, (relative) percent.SR = reproducibility standard deviation, in measurement units.R = reproducibility, in measurement units
43、.(R) = reproducibility, (relative) percent.MaterialAverageLevel,%WithinLaboratoriesBetweenLaboratoriesSr r (r) SR R (R)6 2.90 0.0996 0.306 10.6 0.108 0.282 9.762 3.00 0.113 0.320 10.7 0.134 0.379 12.64 3.01 0.116 0.328 10.9 0.133 0.375 12.5TABLE 3 Type 1 PrecisionLead (Normal Level)NOTESr = repeatab
44、ility standard deviation, in measurement units.r = repeatability, in measurement units.(r) = repeatability, (relative) percent.SR = reproducibility standard deviation, in measurement units.R = reproducibility, in measurement units.(R) = reproducibility, (relative) percent.MaterialAverageLevel,%Withi
45、nLaboratoriesBetweenLaboratoriesSr r (r) SR R (R)2 0.82 0.0264 0.0747 9.11 0.0754 0.213 26.04 0.91 0.0296 0.0838 9.23 0.0785 0.222 24.46 0.92 0.0363 0.103 11.2 0.0856 0.242 26.3TABLE 4 Type 1 PrecisionZinc (Low Level)NOTESr = repeatability standard deviation, in measurement units.r = repeatability,
46、in measurement units.(r) = repeatability, (relative) percent.SR = reproducibility standard deviation, in measurement units.R = reproducibility, in measurement units.(R) = reproducibility, (relative) percent.MaterialAverageLevel,mg/kgWithinLaboratoriesBetweenLaboratoriesSr r (r) SR R (R)A 1.5 0.642 2
47、.108 141. 0.745 1.817 121.B 8.6 1.357 3.840 44.7 1.422 4.02 46.7C 25.8 1.855 5.25 20.4 6.01 17.0 65.9D4004 06 (2012)3widely accepted that its effect is less severe than in the case ofnatural rubber. Possibly for this reason, the determination ofcopper in compounds based on the synthetic rubbers is l
48、essfrequently carried out.615. Limitations15.1 This test method should not be used for copper contentof heavily loaded rubbers, which contain silica and clay, unlessit has been determined that these fillers do not interfere with thetest method as written.16. Apparatus16.1 See Section 5.17. Reagents1
49、7.1 See Section 6.18. Sampling18.1 See Section 7.19. Sample Preparation19.1 Raw rubber may be milled or cut into small pieces.19.2 Latex should be prepared in the form of a filmaccording to Specification D1076, Section 5. It is not necessaryto weigh the sample prior to film preparation.20. Procedure20.1 Weigh a 0.1 g sample of dry rubber to the nearest0.1 mg, prepared according to 19.1 or 19.2, if the coppercontent is above 0.5 %, or a 10 g sample weighed to the nearest0.01 g if the copper content is lower than this.20.2 Place the test portion i
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