1、Designation: D6047 99 (Reapproved 2014)Standard Test Methods forRubber, RawDetermination of 5-Ethylidenenorbornene(ENB) or Dicyclopentadiene (DCPD) in Ethylene-Propylene-Diene (EPDM) Terpolymers1This standard is issued under the fixed designation D6047; the number immediately following the designati
2、on indicates the year oforiginal adoption or, in the 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.1. Scope1.1 These test methods cover the determ
3、ination of thecontent of 5-ethylidenenorbornene (ENB) or Dicyclopentadi-ene (DCPD) in ethylene-propylene-diene (EPDM) terpoly-mers. They are applicable to diene contents in the 0.1 to 10mass % range.1.2 ENB and DCPD are dienes introduced in ethylene/propylene rubbers to generate specific cure proper
4、ties. Sincehigh precision for diene content determination has becomevery important, a Fourier Transform Infrared Spectroscopic(FTIR) method was developed. Diene determination wasperformed in the past by a refractive index technique.NOTE 1The procedures for % ENB and % DCPD differ only in thelocation
5、 in the infrared (IR) of the IR peak being quantified.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespons
6、ibility 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. Referenced Documents2.1 ASTM Standards:2D297 Test Methods for Rubber ProductsChemical Analy-sisD1416 Test Methods for Rubber from Synt
7、hetic SourcesChemical Analysis (Withdrawn 1996)3D3568 Test Methods for RubberEvaluation of EPDM(Ethylene Propylene Diene Terpolymers) Including Mix-tures With OilD3900 Test Methods for RubberDetermination of Ethyl-ene Units in Ethylene-Propylene Copolymers (EPM) andin Ethylene-Propylene-Diene Terpol
8、ymers (EPDM) byInfrared SpectrometryD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustriesE168 Practices for General Techniques of Infrared Quanti-tative AnalysisE932 Practice for Describing and Measuring Performance ofDispersive Infra
9、red SpectrometersE1421 Practice for Describing and Measuring Performanceof Fourier Transform Mid-Infrared (FT-MIR) Spectrom-eters: Level Zero and Level One Tests2.2 ANCHA Document:4Specification for Evaluation of Research Quality Analysisof Infrared Spectra3. Summary of Test Methods3.1 The test spec
10、imen is molded between two PTFE-coatedaluminum or Mylar sheets. The ENB content is determinedfrom its infrared absorbance at 16811690 cm1, a measure ofENBs exocyclic double bond. The DCPD content is deter-mined from its infrared absorbance at 16051610 cm1,ameasure of DCPDs monocyclic double bond.3.2
11、 The second derivative of the absorbance is calculatedand ratioed to an internal thickness gage. For ENB the resultingsecond derivative peak near 1690 cm1is related to ENB massfraction by calibrating the instrument with known EPDMstandards. For DCPD, the resulting second derivative peak near1610 cm1
12、is related to DCPD mass fraction by calibrating theinstrument with known EPDM standards.3.3 Two main steps are performed in this procedure: auto-matic determination of film thickness and quantification ofdiene.1These test methods are under the jurisdiction of Committee D11 on Rubber andare the direc
13、t responsibility of Subcommittee D11.11 on Chemical Analysis.Current edition approved Aug. 1, 2014. Published November 2014. Originallyapproved in 1996. Last previous edition approved in 2009 as D6047 99 (2009).DOI: 10.1520/D6047-99R14.2For referenced ASTM standards, visit the ASTM website, www.astm
14、.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.3The last approved version of this historical standard is referenced onwww.astm.org.4“Specification for Evaluation of Researc
15、h Quality Analysis of InfraredSpectra,” Analytical Chemistry, ANCHA, Vol 47, No. 11, p. 94a.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.4 For oil-extended polymers, the oil must be extractedbefore diene is determined. Test Metho
16、ds D1416, Sections 67through 74 and Test Methods D297 can be used for thispurpose.4. Apparatus4.1 Press, Carver-type, capable of pressing films at 150Cand 10 MPa.4.1.1 Primary MoldA stainless steel (SS) mold, 400 mthick, with an opening sized appropriately for the specimenfilm holder described in 4.
17、4 (2 cm by 2 cm). The mold shouldhave approximately the same dimensions as the press platens.4.1.2 Alternate MoldA thinner mold may be used;however, precision may be adversely affected at low dienelevels. Test precision should be determined when thinner filmsare utilized. Example: a 127-m (0.005-in)
18、 SS shim with a 15-by 35-mm opening may be used for the simultaneous determi-nation of ethylene (Test Methods D3900) and diene.4.1.3 Alternative Mold for Low Molecular Weight (Liquid)EPDM TerpolymersFor liquid EPDM a ring washer 22 mmOD by 16 mm ID (7/8 in OD by 5/8 inch in ID) 400 m thickis used as
19、 a apacer between salt plates (NaBr, NaCl) to set afixed path length. The spacer is sized to cover only the outeredge of the salt plate.4.2 Sheets for Molding, either PTFE-coated aluminumsheets or Mylar, Type A, 36 m thick.4.3 Specimen Film HoldersFilms may be molded, cut, andtransferred to a film h
20、older. Magnetic film holders are ideal.Alternatively, a mold sized to fit in the spectrometer specimencompartment, with an appropriate size opening may be used tosupport the film without removal after pressing.4.4 Infrared Fourier Transform SpectrophotometerAn in-strument capable of measuring absorb
21、ances in the range40006000 cm1with a transmittance specification (accuracy)of 6 1%T or better. The instrument should be capable ofspectral resolution of 2 cm1(see “Specification for Evaluationof Research Quality Analysis of Infrared Spectra”). A deuter-ated triglycine sulfate (DTGS) detector should
22、be used. Theinstrument must be operating in accordance with PracticesE168. Practices E932 and E1421 are other important refer-ences.4.4.1 The instrument should be capable of spectralaccumulation, averaging, and subtracting capabilities. Water isthe primary source of interference in this method. Meth
23、ods,physical and electronic, that minimize moisture level andvariation are required to obtain the highest precision. Thepreferred method is use of an instrument equipped with a drygas purge and a specimen shuttle, which permits alternatingand repetitive collection of single beam specimen and back-gr
24、ound spectra (see Section 6). Alternatively, should a speci-men shuttle be unavailable, careful purging of the samplecompartment with dry nitrogen can yield satisfactory results.High precision of calibration standard data is indicative ofadequate purging. When moisture interference is not removedby
25、purging, spectral subtraction of water vapor may be used.Aprocedure for further method development is described inAppendix X1.5. Test Specimen Preparation5.1 Primary MethodPlace 0.20 6 0.05 g of the testspecimen between two PTFE-coated aluminum or Mylar sheetsin the mold. Place the mold between the
26、press platens heated to125 6 5C and apply 4 MPa pressure for 60 6 10 s.5.1.1 Cool the specimen to ambient temperature. Cut a pieceof film approximately 15 by 50 mm. Detach the specimen filmfrom the aluminum or Mylar and position it on the spectro-photometer sample holder window.5.2 Alternate MethodW
27、hen using the thinner mold de-scribed in 4.1.2, place a small piece (0.040.06 g) of testspecimen in the mold opening between two Mylar sheets andpress as in 5.1. Remove the mold from the press, turn it overand press it again, then remove the mold from the press andcool it to ambient temperature. Whe
28、n cool, carefully removethe Mylar sheets, allowing the specimen film to remainattached to the mold.5.3 Alternate Method for Liquid Sample Film PreparationPlace a washer (described in 4.1.3) on top of a salt plate. Placea small amount (about 0.3 g) of liquid EPDM polymer in thecenter of the washer fi
29、lling the hole completely. Place a secondsalt plate on top of the filled washer. Gently placea1kgweighton top of the salt plate/washer assembly and allow theweighted assembly to sit for 2 to 3 min. (For viscous samplesit may be necessary to warm the sample prior to pressing.)Remove the weight and al
30、low to cool, if necessary. Wipe offany excess material that may have been pressed out of theassembly. Hold the assembly up to the light and inspect forbubbles or voids, or both. Should there be imperfections, repeatthe sample preparation with a larger amount of sample.6. Spectral Acquisition6.1 With
31、 a specimen shuttle:6.1.1 Data acquisition parameters:6.1.1.1 Resolution: 2 cm1.6.1.1.2 Scans/Scan time: Total scan time required, splitbetween specimen and background, is about 90 s.6.1.2 Place the test specimen in the specimen compartment,allow purge to reestablish, and in alternating fashion, col
32、lectsingle beam specimen (P) and “empty specimen compartment”(P0) spectra. Eight passes of the shuttle should be sufficient(eight specimen and eight empty compartment collections),collecting four scans at each position.6.1.3 Calculate the specimen absorbance spectrum as minusthe log10of the ratio of
33、 the accumulated single beam specimenspectrum to the single beam empty specimen compartmentspectrum:A 52log10P/P0! (1)6.2 Without a specimen shuttle:6.2.1 Data acquisition parameters:6.2.1.1 Resolution: 2 cm1.6.2.1.2 Scans/Scan Time: Background scan: 32 scans, 20 stotal; specimen scan: 32 scans, 20
34、s total.6.2.2 Establish dry atmosphere inside empty specimen com-partment and collect “empty specimen compartment” (P0)spectra.D6047 99 (2014)26.2.3 Place test specimen in the specimen compartment andre-establish a dry atmosphere inside the specimen compart-ment. Collect single beam specimen spectra
35、 (P) and calculatethe specimen absorption spectra (A) as described in 6.1.3.7. Calibration of the Spectrophotometer7.1 Obtain a series of known standards covering the 010mass % diene range. Calibration may be based on secondarystandards qualified by other laboratories using this method or,more gener
36、ally, by primary standards whose diene content iswell known. Primary standards may be established via use of1H Nuclear Magnetic Resonance (NMR), in conjunction withother techniques. The calibration standards employed in thedevelopment of this method were determined by a combinationof refractive inde
37、x and1H NMR (utilizing samples dissolved indeuterated o-dichlorobenzene at 120C; the ENB assignmentwas based exclusively on the exocyclic olefinic protons ofENB). The use of four standards at the 0 (copolymer), 2, 5, and10 mass % levels are the minimum recommended.57.2 Using the procedures in Sectio
38、n 6, acquire a minimumof five absorbance spectra for each of the calibration standardsdescribed in 7.1. Several repetitions on separate specimens ofeach standard may be averaged to improve the accuracy of thecalibration.7.3 Using the procedures in Section 8, calculate the ratio ofthe second derivati
39、ve diene peak height to the internal thick-ness gage for each of the spectra acquired.7.4 Calculate a linear calibration line (diene peak ratioversus assigned values of the standards in mass % diene) bycomputing a slope and intercept using standard least squareslinear regression techniques.8. Diene
40、Determination8.1 Prepare the specimen film as described in Section 5.8.2 Collect a single absorbance spectrum based on theprocedure in Section 6.8.3 Determination of Film Thickness:8.3.1 Normalize the spectrum by bringing the lowest pointof the spectrum to zero (that is, determine the minimumabsorba
41、nce in the spectrum and offset the spectrum to bring theabsorbance to zero).8.3.2 To determine the film thickness automatically, calcu-late the difference of the absorbance at 2703 cm1minus the5The sole source of supply for the ENB standards known to the committee at thistime is Exxon Chemical Polym
42、er Laboratories, P.O. Box 5200, Baytown,TX 77522.The sole source of supply for the DCPD standards known to the committee at thistime is UniRoyal Chemical Company, Chemical Characterization Lab, BensonRoad, Middlebury, CT 06749. If you are aware of alternative suppliers, pleaseprovide this informatio
43、n to ASTM Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.FIG. 1 FT-IR Thickness GageGroup DeterminationD6047 99 (2014)3absorbance at 2750 cm1. If the net difference is positive, thesample belongs to Group 1. Othe
44、rwise, it belongs to Group 2(see Fig. 1).8.3.2.1 Group 1: Thickness gage is the net absorbancedifference between 2708 cm1(isooptic point) and 2450 cm1(anchor point) (see Fig. 2).8.3.2.2 Group 2: Thickness gage is the net absorbancedifference between 2668 cm1(isooptic point) and 2450 cm1(anchor point
45、) (see Fig. 3).8.4 Diene Quantitation:8.4.1 Normalize the total spectrum to one optical density(OD) by multiplying the total spectrum by 1/A, where A is thenet absorbance at thickness gage.8.4.2 ENB Calculation: Calculate the peak height (in OD)of the second derivative (the second derivative algorit
46、hmshould use nine point smoothing) between 1681 and 1690 cm1by applying the following formula:Peak Ht 5 A16812 0.75 A168810.25 A1689! (2)This will be called the ENB peak height throughout thisprocedure. Fig. 4 gives a visual impression of a typical secondderivative spectrum of EPDM.8.4.3 Use the cal
47、ibration developed in Section 8.4.2 tocompute a mass % ENB for the sample, employing theprinciple that only interpolation (and not extrapolation) is used.If the ENB peak height determined in 8.4.5 is lower than theENB peak height of the lowest, or higher than the ENB peakheight of the highest calibr
48、ation standard, then the ENB mass% should be reported as “out of range for the calibrationemployed.”8.4.4 DCPD CalculationCalculate the peak height (inOD) of the second derivative (the second derivative algorithmshould use nine point smoothing) between 1601 and 1620 cm1by applying the following form
49、ula:Peak Ht 5 A16012 A1610! (3)This will be called the DCPD peak height throughout thisprocedure.8.4.5 Use the calibration developed in Section 8.4.4 tocompute a mass % DCPD for the sample, employing theprinciple that only interpolation (and not extrapolation) is used.If the DCPD peak height determined in 8.4.5 is lower than theDCPD peak height of the lowest, or higher than the DCPDpeak height of the highest calibration standard, then the DCPDmass % should be reported as “out of range for the calibrationemployed.”9. Report9.1 Report
