1、Designation: D 6047 99 (Reapproved 2003)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 D 6047; the number immediately following the designa
2、tion 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the det
3、ermination 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 pro
4、perties. 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 thelocat
5、ion in the infrared (IR) of the IR peak being quantified.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theres
6、ponsibility 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:2D 297 Test Methods for Rubber ProductsChemicalAnalysisD 1416 Test Methods for Rubber from
7、Synthetic SourcesChemical Analysis3D 3568 Test Methods for RubberEvaluation of EPDM(Ethylene Propylene Diene Terpolymers) Including Mix-tures with OilD 3900 Test Methods for Rubber, RawDetermination ofEthylene Units in EPM (Ethylene-Propylene Copolymers)and EPDM (Ethylene-Propylene-Diene Terpolymers
8、)D 4483 Practice for Determining Precision for Test MethodStandards in the Rubber and Carbon Black IndustriesE 168 Practices for General Techniques of Infrared Quanti-tative AnalysisE 932 Practices for Describing and Measuring Performanceof Dispersive SpectrophotometersE 1421 Practice for Describing
9、 and Measuring Performanceof Fourier Transform Mid-Infrared (FT-MIR) Spectropho-tometers: Level Zero and Level One Tests2.2 ANCHA Document:Specification for Evaluation of Research Quality Analysisof Infrared Spectra43. Summary of Test Methods3.1 The test specimen is molded between two PTFE-coatedalu
10、minum 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 The second derivative of the absorbance
11、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 cm1is related to DCPD mass fraction by calib
12、rating 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 direct responsibility of Subcommittee D11.11 o
13、n Chemical Analysis.Current edition approved Nov. 1, 2003. Published December 2003. Originallyapproved in 1996. Last previous edition approved in 1999 as D 604799e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Bo
14、ok of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4“Specification for Evaluation of Research Quality Analysis of Infrared Spec-tra,” Analytical Chemistry, ANCHA, Vol 47, No. 11, p. 94a.1Copyright ASTM International, 100 Barr Harbor Dri
15、ve, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.4 For oil-extended polymers, the oil must be extractedbefore diene is determined. Test Methods D 1416, Sections 67through 74 and Test Methods D 297 can be used for thispurpose.4. Apparatus4.1 Press, Carver-type, capable of pressing f
16、ilms 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 4.4 (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
17、; how-ever, precision may be adversely affected at low diene levels.Test precision should be determined when thinner films areutilized. Example: a 127-m (0.005-in) SS shim with a 15- by35-mm opening may be used for the simultaneous determina-tion of ethylene (Test Methods D 3900) and diene.4.1.3 Alt
18、ernative 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 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.
19、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,and transferred to a film holder. Magnetic film holders areideal. Alternatively, a mold sized to fit in the spectrometerspecimen compartment, with an appropriate s
20、ize opening maybe used to support the film without removal after pressing.4.4 Infrared Fourier Transform SpectrophotometerAn in-strument capable of measuring absorbances in the range40006000 cm1with a transmittance specification (accuracy)of 6 1% T or better. The instrument should be capable ofspect
21、ral resolution of 2 cm1(see “Specification for Evaluationof Research Quality Analysis of Infrared Spectra”). A deuter-ated triglycine sulfate (DTGS) detector should be used. Theinstrument must be operating in accordance with PracticesE 168. Practices E 932 and E 1421 are other important refer-ences.
22、4.4.1 The instrument should be capable of spectral accumu-lation, averaging, and subtracting capabilities. Water is theprimary source of interference in this method. Methods,physical and electronic, that minimize moisture level andvariation are required to obtain the highest precision. Thepreferred
23、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-ground spectra (see Section 6). Alternatively, should a speci-men shuttle be unavailable, careful purging of the samplecompartment w
24、ith dry nitrogen can yield satisfactory results.High precision of calibration standard data is indicative ofadequate purging. When moisture interference is not removedby purging, spectral subtraction of water vapor may be used. Aprocedure for further method development is described inAppendix X1.5.
25、Test Specimen Preparation5.1 Primary Method Place 0.20 6 0.05 g of the testspecimen between two PTFE-coated aluminum or Mylar sheetsin the mold. Place the mold between the 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 pie
26、ceof 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 Method When using the thinner mold de-scribed in 4.2.2, place a small piece (0.040.06 g) of testspecimen in the mold opening between tw
27、o 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. When cool, carefully removethe Mylar sheets, allowing the specimen film to remainattached to the mold.5.3 Alternate Method for Liq
28、uid Sample FilmPreparationPlace a washer (described in 4.1.3) on top of asalt plate. Place a small amount (about 0.3 g) of liquid EPDMpolymer in the center of the washer filling the hole completely.Place a second salt plate on top of the filled washer. Gentlyplacea1kgweight on top of the salt plate/
29、washer assemblyand allow the weighted assembly to sit for 2-3 min. (Forviscous samples it may be necessary to warm the sample priorto pressing.) Remove the weight and allow to cool, if neces-sary. Wipe off any excess material that may have been pressedout of the assembly. Hold the assembly up to the
30、 light andinspect for bubbles and/or voids. Should there be imperfec-tions, repeat the sample preparation with a larger amount ofsample.6. Spectral Acquisition6.1 With 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, sp
31、litbetween 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, collectsingle beam specimen (P) and “empty specimen compartment”(P0) spectra. Eight passes of the shuttle should be sufficient(eight spe
32、cimen 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 the accumulated single beam specimenspectrum to the single beam empty specimen compartmentspectrum:A 52log10P/P0! (1)6.2 Without a s
33、pecimen 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, 20seconds total; specimen scan: 32 scans, 20 seconds total.6.2.2 Establish dry atmosphere inside empty specimen com-partment and collect “empty specimen compartment” ( P0)s
34、pectra.D 6047 99 (2003)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 (P) and calculatethe specimen absorption spectra (A) as described in 6.1.3.7. Calibration of the Spectrophotometer7.1
35、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 generally, by primary standards whose diene content iswell known. Primary standards may be established via use of1H Nuclear
36、Magnetic Resonance (NMR), in conjunction withother techniques. The calibration standards employed in thedevelopment of this method were determined by a combinationof refractive index and1H NMR (utilizing samples dissolvedin deuterated o-dichlorobenzene at 120C; the ENB assign-ment was based exclusiv
37、ely on the exocyclic olefinic protonsof ENB). The use of four standards at the 0 (copolymer), 2, 5,and 10 mass % levels are the minimum recommended.57.2 Using the procedures in Section 6, acquire a minimumof five absorbance spectra for each of the calibration standardsdescribed in 7.1. Several repet
38、itions 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 derivative diene peak height to the internal thick-ness gage for each of the spectra acquired.7.4 Calculate a linear calibrat
39、ion 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 Determination8.1 Prepare the specimen film as described in Section 5.8.2 Collect a single absorbance spectrum based o
40、n 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 minimumabsorbance in the spectrum and offset the spectrum to bring theabsorbance to zero).8.3.2 To determine the film thickness aut
41、omatically, calcu-late the difference of the absorbance at 2703 cm1minus theabsorbance at 2750 cm1. If the net difference is positive, thesample belongs to Group 1. Otherwise, it belongs to Group 2(see Fig. 1).5The sole source of supply for the ENB standards known to the committee at thistime is Exx
42、on Chemical Polymer 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, pleaseprovi
43、de this information 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 DeterminationD 6047 99 (2003)38.3.2.1 Group 1: Thickness gage is the net absorbancedifference between 27
44、08 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) (see Fig. 3).8.4 Diene Quantitation:8.4.1 Normalize the total spectrum to one optical density(OD) by multiplying
45、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 algorithm should use nine point smooth-ing) between 1681 and 1690 cm1by applying the followingformula:Peak Ht 5 A16812 0.75
46、 A16881 0.25 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 calibration developed in Section 8.4.2 tocompute a mass % ENB for the sample, employing theprinciple that only interp
47、olation (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 calibration standard, then the ENB mass% should be reported as “out of range for the calibrationemployed.”8.4.4 DCPD Cal
48、culation:Calculate the peak height (in OD) of the second derivative(the second derivative algorithm should use nine point smooth-ing) between 1601 and 1620 cm1by applying the followingformula:Peak Ht 5 A1601 A1610! (3)This will be called the DCPD peak height throughout thisprocedure.8.4.5 Use the ca
49、libration 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 the following information:9.1.1 ENB content to two decimal places:ENB 5 xx.xx mass %DCPD 5 xx.xx mass %9.1.2 Type
