1、Designation: D6047 17Standard 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 designation indicates the y
2、ear 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 determination of thecont
3、ent 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 properties. Sincehigh pr
4、ecision 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 in the infrared (
5、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 theresponsibility of the use
6、r of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in
7、the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D297 Test Methods for Rubber ProductsChemical Analy-sisD1416 Test Methods
8、 for Rubber from Synthetic SourcesChemical Analysis (Withdrawn 1996)3D3568 Test Methods for RubberEvaluation of EPDM(Ethylene Propylene Diene Terpolymers) Including Mix-tures With OilD3900 Test Methods for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-P
9、ropylene-Diene Terpolymers (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 Performan
10、ce ofDispersive Infrared 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 Met
11、hods3.1 The test specimen 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 monoc
12、yclic double bond.3.2 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 EPDM1These test methods are under the jurisdiction of
13、 Committee D11 on Rubber andRubber-like Materials and are the direct responsibility of Subcommittee D11.11 onChemical Analysis.Current edition approved Oct. 1, 2017. Published October 2017. Originallyapproved in 1996. Last previous edition approved in 2015 as D6047 15. DOI:10.1520/D6047-17.2For refe
14、renced 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.3The last approved version of this historical standard is referenced o
15、nwww.astm.org.4“Specification for Evaluation of Research 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 StatesThis international standard was develope
16、d in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1standards. For DCPD, t
17、he resulting second derivative peak near1610 cm1is 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.3.4 For oil-extended polymers, the oil mus
18、t be extractedbefore diene is determined. Test Methods 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 or higher.4.1.1 Primary MoldA stainless steel (SS) mold, approxi-mately 400 m thick, w
19、ith an opening sized appropriately forthe specimen film holder described in 4.4 (typically 2 by 2 cm).The mold should have approximately the same dimensions asthe press platens.4.1.2 Alternate MoldA thinner mold may be used;however, precision may be adversely affected at low dienelevels. Test precis
20、ion should be determined when thinner filmsare utilized. Example: a 127-m (0.005-in) 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
21、 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.4.2 Sheets for Molding, either PTFE-coated aluminumsheets or Mylar, Type A, 36 m
22、 thick or less.4.3 Specimen Film HoldersFilms may be molded, cut, andtransferred to a film holder. 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 pressin
23、g.4.4 Infrared Fourier Transform SpectrophotometerAn in-strument capable of measuring absorbances in the range 400 to6000 cm1with a transmittance specification (accuracy) of 61%T or better. The instrument should be capable of spectralresolution of 2 cm1(see “Specification for Evaluation ofResearch Q
24、uality Analysis of Infrared Spectra”). A deuteratedtriglycine sulfate (DTGS) detector should be used. The instru-ment must be operating in accordance with Practices E168.Practices E932 and E1421 are other important references.4.4.1 The instrument should be capable of spectralaccumulation, averaging,
25、 and subtracting capabilities. Water isthe primary source of interference in this method. Methods,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 s
26、huttle, 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 with dry nitrogen can yield satisfactory results.High precision of calibratio
27、n 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. Test Specimen Preparation5.1 Primary MethodPlace an appropriate amount of the
28、test specimen to fill the mold opening (typically 0.2 to 0.5 g)between two PTFE-coated aluminum or Mylar sheets in themold. Place the mold between the press platens heated to 1256 5C and apply approximately 10 MPa or higher pressure for60 6 10 s.NOTE 2High molecular weight polymers may require highe
29、r tempera-tures and pressures to obtain a good test specimen.5.1.1 Cool the specimen to ambient temperature. Cut, ifnecessary, a piece of film to the appropriate size to cover thespecimen holder window. Detach the specimen film from thealuminum or Mylar and position it on the spectrophotometersample
30、 holder window.5.2 Alternate MethodWhen 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 an
31、dcool it to ambient temperature. When 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 p
32、olymer in thecenter of the washer filling 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 t
33、o pressing.)Remove the weight and allow 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 sa
34、mple.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, splitbetween specimen and background, is about 90 s.6.1.2 Place the test specimen in the specimen compartment,allow purge to reestabl
35、ish, and in alternating fashion, collectsingle 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.D6047 1726.1.3 Calculate the specimen absorba
36、nce 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 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 s
37、cans, 20 stotal; specimen scan: 32 scans, 20 s total.6.2.2 Establish dry atmosphere inside empty specimen com-partment and collect “empty specimen compartment” (P0)spectra.6.2.3 Place test specimen in the specimen compartment andre-establish a dry atmosphere inside the specimen compart-ment. Collect
38、 single beam specimen spectra (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 us
39、ing this method or,more generally, 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
40、combinationof refractive index 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 U
41、sing the procedures in Section 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 th
42、e ratio ofthe second derivative 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 re
43、gression techniques.8. Diene 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 Correct the offset of the spectrum by bringing thelowest point of the spectrum to ze
44、ro (that is, determine theminimum absorbance in the spectrum and offset the spectrumto bring the absorbance to zero).8.3.2 To determine the film thickness automatically, calcu-late the difference of the absorbance at the basepoint near 2703cm1minus the absorbance at the basepoint near 2750 cm1.Ifthe
45、 net difference is positive, the sample belongs to Group 1.Otherwise, 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 absorbancediffe
46、rence 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 the total spectrum by 1/A, where A is thenet absorbance at thickness gage.8.4.2 ENB CalculationCalculate the peak height
47、(in OD)of the second derivative (the second derivative algorithmshould use at least nine point smoothing) between 1681 and1690 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 impre
48、ssion 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 interpolation (and not extrapolation) is used.If the ENB peak height determined in 8.4.5 is lower than theENB peak height
49、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 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 formula: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
