1、Designation: D6047 15D6047 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 indicat
2、es 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 determination of
3、 the content of 5-ethylidenenorbornene (ENB) or Dicyclopentadiene (DCPD)in ethylene-propylene-diene (EPDM) terpolymers. They are applicable to diene contents in the 0.1 to 10 mass % range.1.2 ENB and DCPD are dienes introduced in ethylene/propylene rubbers to generate specific cure properties. Since
4、 highprecision for diene content determination has become very important, a Fourier Transform Infrared Spectroscopic (FTIR) methodwas developed. Diene determination was performed in the past by a refractive index technique.NOTE 1The procedures for % ENB and % DCPD differ only in the location in the
5、infrared (IR) of the IR peak being quantified.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibil
6、ityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardiz
7、ationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D297 Test Methods for Rubber ProductsChemical Analysi
8、sD1416 Test Methods for Rubber from Synthetic SourcesChemical Analysis (Withdrawn 1996)3D3568 Test Methods for RubberEvaluation of EPDM (Ethylene Propylene Diene Terpolymers) Including Mixtures With OilD3900 Test Methods for RubberDetermination of Ethylene Units in Ethylene-Propylene Copolymers (EPM
9、) and inEthylene-Propylene-Diene Terpolymers (EPDM) by Infrared SpectrometryD4483 Practice for Evaluating Precision for Test Method Standards in the Rubber and Carbon Black Manufacturing IndustriesE168 Practices for General Techniques of Infrared Quantitative AnalysisE932 Practice for Describing and
10、 Measuring Performance of Dispersive Infrared SpectrometersE1421 Practice for Describing and Measuring Performance of Fourier Transform Mid-Infrared (FT-MIR) Spectrometers: LevelZero and Level One Tests2.2 ANCHA Document:4Specification for Evaluation of Research Quality Analysis of Infrared Spectra3
11、. Summary of Test Methods3.1 The test specimen is molded between two PTFE-coated aluminum or Mylar sheets. The ENB content is determined fromits infrared absorbance at 16811690 cm1, a measure of ENBs exocyclic double bond. The DCPD content is determined fromits infrared absorbance at 16051610 cm1, a
12、 measure of DCPDs monocyclic double bond.1 These test methods are under the jurisdiction of Committee D11 on Rubber and Rubber-like Materials and are the direct responsibility of Subcommittee D11.11 onChemical Analysis.Current edition approved Nov. 1, 2015Oct. 1, 2017. Published December 2015October
13、 2017. Originally approved in 1996. Last previous edition approved in 20142015as D6047 99 (2014).D6047 15. DOI: 10.1520/D6047-15.10.1520/D6047-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standards
14、volume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.4 “Specification for Evaluation of Research Quality Analysis of Infrared Spectra,” Analytical Chemistry, ANCHA, Vol 47, No. 11, p
15、. 94a.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult pri
16、or editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 The second derivative of the absorbanc
17、e is calculated and ratioed to an internal thickness gage. For ENB the resultingsecond derivative peak near 1690 cm1 is related to ENB mass fraction by calibrating the instrument with known EPDM standards.For DCPD, the resulting second derivative peak near 1610 cm1 is related to DCPD mass fraction b
18、y calibrating the instrumentwith known EPDM standards.3.3 Two main steps are performed in this procedure: automatic determination of film thickness and quantification of diene.3.4 For oil-extended polymers, the oil must be extracted before diene is determined. Test Methods D1416, Sections 67 through
19、74 and Test Methods D297 can be used for this purpose.4. Apparatus4.1 Press, Carver-type, capable of pressing films at 150C and 10 MPa or higher.4.1.1 Primary MoldA stainless steel (SS) mold, approximately 400 m thick, with an opening sized appropriately for thespecimen film holder described in 4.4
20、(typically 2 by 2 cm). The mold should have approximately the same dimensions as the pressplatens.4.1.2 Alternate MoldA thinner mold may be used; however, precision may be adversely affected at low diene levels. Testprecision should be determined when thinner films are utilized. Example: a 127-m (0.
21、005-in) SS shim with a 15- by 35-mmopening may be used for the simultaneous determination 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 mm ODby 16 mm ID (7/8 in OD by 5/8 inch in ID) 400 m thick is
22、 used as a apacer between salt plates (NaBr, NaCl) to set a fixed pathlength. The spacer is sized to cover only the outer edge of the salt plate.4.2 Sheets for Molding, either PTFE-coated aluminum sheets or Mylar, Type A, 36 m thick or less.4.3 Specimen Film HoldersFilms may be molded, cut, and tran
23、sferred to a film holder. Magnetic film holders are ideal.Alternatively, a mold sized to fit in the spectrometer specimen compartment, with an appropriate size opening may be used tosupport the film without removal after pressing.4.4 Infrared Fourier Transform SpectrophotometerAn instrument capable
24、of measuring absorbances in the range 400 to 6000cm1 with a transmittance specification (accuracy) of 6 1 % T or better. The instrument should be capable of spectral resolutionof 2 cm1 (see “Specification for Evaluation of Research Quality Analysis of Infrared Spectra”). A deuterated triglycine sulf
25、ate(DTGS) detector should be used. The instrument must be operating in accordance with Practices E168. Practices E932 and E1421are other important references.4.4.1 The instrument should be capable of spectral accumulation, averaging, and subtracting capabilities. Water is the primarysource of interf
26、erence in this method. Methods, physical and electronic, that minimize moisture level and variation are requiredto obtain the highest precision. The preferred method is use of an instrument equipped with a dry gas purge and a specimen shuttle,which permits alternating and repetitive collection of si
27、ngle beam specimen and background spectra (see Section 6).Alternatively,should a specimen shuttle be unavailable, careful purging of the sample compartment with dry nitrogen can yield satisfactoryresults. High precision of calibration standard data is indicative of adequate purging. When moisture in
28、terference is not removedby purging, spectral subtraction of water vapor may be used.Aprocedure for further method development is described in AppendixX1.5. Test Specimen Preparation5.1 Primary MethodPlace an appropriate amount of the test specimen to fill the mold opening (typically 0.2 to 0.5 g) b
29、etweentwo PTFE-coated aluminum or Mylar sheets in the mold. Place the mold between the press platens heated to 125 6 5C and applyapproximately 10 MPa or higher pressure for 60 6 10 s.NOTE 2High molecular weight polymers may require higher temperatures and pressures to obtain a good test specimen.5.1
30、.1 Cool the specimen to ambient temperature. Cut, if necessary, a piece of film to the appropriate size to cover the specimenholder window. Detach the specimen film from the aluminum or Mylar and position it on the spectrophotometer sample holderwindow.5.2 Alternate MethodWhen using the thinner mold
31、 described in 4.1.2, place a small piece (0.040.06 g) of test specimen inthe mold opening between two Mylar sheets and press as in 5.1. Remove the mold from the press, turn it over and press it again,then remove the mold from the press and cool it to ambient temperature. When cool, carefully remove
32、the Mylar sheets, allowingthe specimen film to remain attached 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. Place asmall amount (about 0.3 g) of liquid EPDM polymer in the center of the washer filling the hole complete
33、ly. Place a second saltplate on top of the filled washer. Gently place a 1 kg weight on top of the salt plate/washer assembly and allow the weightedassembly to sit for 2 to 3 min. (For viscous samples it may be necessary to warm the sample prior to pressing.) Remove the weightD6047 172and allow to c
34、ool, if necessary. Wipe off any excess material that may have been pressed out of the assembly. Hold the assemblyup to the light and inspect for bubbles or voids, or both. Should there be imperfections, repeat the sample preparation with a largeramount of sample.6. Spectral Acquisition6.1 With a spe
35、cimen 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, split between 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, collect
36、 singlebeam specimen (P) and “empty specimen compartment” (P0) spectra. Eight passes of the shuttle should be sufficient (eightspecimen and eight empty compartment collections), collecting four scans at each position.6.1.3 Calculate the specimen absorbance spectrum as minus the log10 of the ratio of
37、 the accumulated single beam specimenspectrum to the single beam empty specimen compartment spectrum:A 52log 10P/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 s total; specimen scan: 32 scans,
38、20 s total.6.2.2 Establish dry atmosphere inside empty specimen compartment and collect “empty specimen compartment” (P0) spectra.6.2.3 Place test specimen in the specimen compartment and re-establish a dry atmosphere inside the specimen compartment.Collect single beam specimen spectra (P) and calcu
39、late the specimen absorption spectra (A) as described in 6.1.3.7. Calibration of the Spectrophotometer7.1 Obtain a series of known standards covering the 010 mass % diene range. Calibration may be based on secondary standardsqualified by other laboratories using this method or, more generally, by pr
40、imary standards whose diene content is well known.Primary standards may be established via use of 1H Nuclear Magnetic Resonance (NMR), in conjunction with other techniques.The calibration standards employed in the development of this method were determined by a combination of refractive index and1H
41、NMR (utilizing samples dissolved in deuterated o-dichlorobenzene at 120C; the ENB assignment was based exclusively onthe exocyclic olefinic protons of ENB).The use of four standards at the 0 (copolymer), 2, 5, and 10 mass % levels are the minimumrecommended.57.2 Using the procedures in Section 6, ac
42、quire a minimum of five absorbance spectra for each of the calibration standardsdescribed in 7.1. Several repetitions on separate specimens of each standard may be averaged to improve the accuracy of thecalibration.7.3 Using the procedures in Section 8, calculate the ratio of the second derivative d
43、iene peak height to the internal thicknessgage for each of the spectra acquired.7.4 Calculate a linear calibration line (diene peak ratio versus assigned values of the standards in mass % diene) by computinga slope and intercept using standard least squares linear regression techniques.8. Diene Dete
44、rmination8.1 Prepare the specimen film as described in Section 5.8.2 Collect a single absorbance spectrum based on the procedure in Section 6.8.3 Determination of Film Thickness:8.3.1 Correct the offset of the spectrum by bringing the lowest point of the spectrum to zero (that is, determine the mini
45、mumabsorbance in the spectrum and offset the spectrum to bring the absorbance to zero).8.3.2 To determine the film thickness automatically, calculate the difference of the absorbance at the basepoint near 2703 cm1minus the absorbance at the basepoint near 2750 cm1. If the net difference is positive,
46、 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 absorbance difference between 2708 cm1 (isooptic point) and 2450 cm1 (anchorpoint) (see Fig. 2).5 The sole source of supply for the ENB standards known to the committee at this tim
47、e is ExxonMobil Chemical Polymer Laboratories, P.O. Box 5200, Baytown, TX77520. The sole source of supply for the DCPD standards known to the committee at this time is UniRoyal Chemical Company, Chemical Characterization Lab, Benson Road,Middlebury, CT 06749. If you are aware of alternative supplier
48、s, please provide this information to ASTM Headquarters. Your comments will receive careful considerationat a meeting of the responsible technical committee,1 which you may attend.D6047 1738.3.2.2 Group 2: Thickness gage is the net absorbance difference between 2668 cm1 (isooptic point) and 2450 cm1
49、 (anchorpoint) (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 the netabsorbance at thickness gage.8.4.2 ENB CalculationCalculate the peak height (in OD) of the second derivative (the second derivative algorithm should useat least nine point smoothing) between 1681 and 1690 cm1 by applying the following formula:Peak Ht5A168120.75 A168810.25 A1689! (2)This will be called the ENB peak height throughout this procedure. Fig. 4 gives
