1、Designation: D5576 00 (Reapproved 2013)Standard Practice forDetermination of Structural Features in Polyolefins andPolyolefin Copolymers by Infrared Spectrophotometry (FT-IR)1This standard is issued under the fixed designation D5576; the number immediately following the designation indicates the yea
2、r 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. Scope*1.1 This practice covers infrared procedures for determini
3、ngthe molecular structural features in polyolefins and polyolefincopolymers. The structural features of primary concern are thetypes and numbers of branches. Although this practice centersits attention on polyolefins and polyolefin copolymers, thetechniques, with proper modification, can be used for
4、 someother polymers as well.NOTE 1Quantitative determinations require either an internal or anexternal evaluation of sample thickness.ASTM test methods available forspecific features are listed in Tables 1 and 2.1.2 This standard does not purport to address all of thesafety concerns, if any, associa
5、ted with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and to determine theapplicability of the regulatory limitations prior to use.NOTE 2There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:
6、2D883 Terminology Relating to PlasticsD1505 Test Method for Density of Plastics by the Density-Gradient TechniqueD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD2238 Test Methods forAbsorbance of Polyethylene Due toMethyl Groups at 1378 cm1D3124 Test Method for Vinylidene Unsaturation i
7、n Polyeth-ylene by Infrared SpectrophotometryD3594 Test Method for Copolymerized Ethyl Acrylate InEthylene-Ethyl Acrylate CopolymersD5594 Test Method for Determination of the Vinyl AcetateContent of Ethylene-Vinyl Acetate (EVA) Copolymers byFourier Transform Infrared Spectroscopy (FT-IR)D6248 Test M
8、ethod for Vinyl and Trans Unsaturation inPolyethylene by Infrared SpectrophotometryE131 Terminology Relating to Molecular SpectroscopyE168 Practices for General Techniques of Infrared Quanti-tative AnalysisE932 Practice for Describing and Measuring Performance ofDispersive Infrared SpectrometersE142
9、1 Practice for Describing and Measuring Performanceof Fourier Transform Mid-Infrared (FT-MIR) Spectrom-eters: Level Zero and Level One TestsIEEE/ASTM SI-10 Standard for Use of the InternationalSystem of Units (SI): The Modern System3. Terminology3.1 DefinitionsFor definitions of plastics terms used
10、inthis practice see Terminology D883 and D1600.3.2 Units, symbols and abbreviations used in this practiceappear in Terminology E131 or IEEE/ASTM SI-10.4. Summary of Practice4.1 Infrared absorption bands suitable for quantitativeanalysis by FT-IR are listed in Tables 1 and 2. These are onlytypical ba
11、nds and are not to be construed as exhaustive.4.2 For quantitative determinations, sample specimen thick-ness is measured internally at some band representing the basicchain structure, such as 2019 cm1for polyethylene, orexternally using a micrometer (see Tables 1 and 2 for ASTMtest methods).NOTE 3W
12、arning: Molding can cause carbonyl formation due tooxidation. This should be checked in the 1700 to 1750 cm1range.5. Significance and Use5.1 The structural features expressed by these determina-tions affect the ultimate polymeric properties and are useful inshowing correlations with many performance
13、 properties.6. Apparatus6.1 Infrared Spectrophotometer, either double beam or aFourier transform (FT-IR).1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.70 on Analytical Methods.Current edition approved April 1, 2013. Publ
14、ished April 2013. Originallyapproved in 1994. Last previous edition approved in 2006 as D5576 - 00(2006).DOI: 10.1520/D5576-00R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informat
15、ion, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.1.1 Double-beam infrared spectrophotometer capable
16、 of a4cm-1spectral resolution as defined in Practice E932. Theinstrument should be capable of scale expansion along thewavelength axis.6.1.2 Fourier Transform Infrared Spectrometer, capable of 4cm1resolution. The instrument should be capable of scaleexpansion along the wavelength axis.Also, see Prac
17、tice E1421for testing procedures.6.2 Hot Plate.6.3 Microscope Slides.6.4 Compression-Molding Press, capable of 200C.6.5 Metal Plates, two, 150 by 150 mm or larger, of 0.5mmthickness with smooth surfaces.6.6 Brass Shims, approximately 75 by 75 mm, of 0.5-mmthickness with an aperture in the center at
18、least 25 by 38 mm.6.7 Micrometer (optional), with thimble graduations of0.001 mm.6.8 Film Mounts, with apertures at least 6 by 27 mm, to holdthe specimens in the infrared spectrophotometer.7. Materials7.1 Polyethylene Terephthalate, Aluminum or Matte Fin-ished Teflon-Fiberglass Sheets.8. Hazards8.1
19、Wear gloves when plaques are prepared using a heatedpress.8.2 The optical bench of the FT-IR spectrometer contains alaser. To avoid eye injury, do not look directly into the laserbeam.9. Procedure9.1 Sample Preparation:9.1.1 Procedure A:9.1.1.1 Control the hot plate temperature at 100 6 10Cabove the
20、 melting temperature of the polymer.9.1.1.2 Place a portion of the sample on a microscope slideon the hot plate.9.1.1.3 Cover the sample with another slide and press witha wooden pestle. Use firm circular motions to press a uniformfilm.9.1.1.4 To quench the pressed polymer film, dip the twoslides ca
21、refully into a beaker of cold water. Remove the filmand blot dry.9.1.2 Procedure B:9.1.2.1 Preheat the press to about 50C above the meltingpoint of the polymer.9.1.2.2 Place a brass shim on the sheet material chosen (see7.1) that, in turn, covers a metal plate.9.1.2.3 Add polymer in sufficient quant
22、ity to completely fillthe shim aperture during pressing.9.1.2.4 Cover with another piece of sheet (see 7.1) andanother metal plate.9.1.2.5 Insert the mold assembly between the press platensand apply a slight pressure.9.1.2.6 Allow the sample to preheat for about 30 s. Applythe full press pressure at
23、 a temperature approximately 50Cabove the melting point of the polymer for 1 min or until allexudation ceases.9.1.2.7 Turn off the heat, turn on the cooling water, andallow the sample to press quench at full pressure until thetemperature drops below 50C (or cool enough to remove themold assembly by
24、hand).9.1.2.8 Release the pressure and remove the sample.9.1.2.9 Select plaques that are clear and of uniform thick-ness for the FT-IR analysis. To avoid interference fringes in thespectrum, the plaque/film surfaces must be slightly dimpled.9.2 Spectral Measurements:9.2.1 Place the sample in the inf
25、rared spectrophotometer.9.2.2 Set the controls of the infrared spectrophotometer forquantitative conditions with a good signal to noise ratio andsatisfactory repeatability. For a FT-IR, a spectral resolution of4cm1and an apodization function (Beer-Norton medium andHapp-Genzel have been found to be a
26、ppropriate) that givesgood quantitation should be used.9.2.3 Record the infrared spectrum from 4000 to 500 cm1.9.2.4 Determine which structural feature(s) are present andselect the appropriate ASTM method for quantitative determi-nation.10. Calculation10.1 If no standard method is available and an e
27、stimate ofthe concentration of the feature of interest is sought, theapproach in 10.1.1-10.1.3 is suggested.10.1.1 Determine the thickness of the plaque or, preferably,its spectral cross-section, b,incm2/g, by measuring thethickness and density or alternatively the mass and surface areaof a uniforml
28、y thick portion of the plaque10.1.2 Measure the absorbance of the peak of interest.Choose a baseline between valleys on either side of the peak ina manner to produce the most accurate and repeatable repre-sentation of the actual background absorbanceTABLE 1 Polyolefin Structural Features Determined
29、by FT-IRStructureAbsorption Band,cm1ASTM Test MethodMethyl group(polyethylene)1378 D2238Methyl group (eth-propcopol)1380Pendant methyl 935Terminal vinyl 908 D6248Trans-vinylene 965 D6248Vinylidene 888 D3124TABLE 2 Structural Features in Polyolefin Copolymer Determinedby FT-IRStructure Absorption Ban
30、d, cm1ASTM Test MethodVinyl acetate 609 D55941020 D55943270 D5594Styrene 77070016001500Ethyl acrylate 16401730862 D3594Ethylene acrylate 1280120016401625D5576 00 (2013)210.1.3 Calculate the concentration, c, of the feature usingeither the Beer-Lambert Law (A = a b c) with the appropri-ate molar abso
31、rptivity, a, or an appropriate calibration curve. Ifa calibration curve is used, it should have a minimum of 5 datapoints, and the unknown should be within the high and lowlimits of the standards.11. Report11.1 Report the following information:11.1.1 Complete identification of material tested includ
32、ingname, manufacturer, lot number and physical form whensampled,11.1.2 Date of test, and11.1.3 Any sample or spectral anomalies observed duringthe measurement.12. Keywords12.1 copolymers; FT-IR; infrared spectrophotometry; poly-ethylene; structural featuresSUMMARY OF CHANGESCommittee D20 has identif
33、ied the location of selected changes to this standard since the last issue(D5576 - 00(2006) that may impact the use of this standard. (April 1, 2013)(1) Reapproved without change.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item me
34、ntionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committe
35、e and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeti
36、ng of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO
37、 Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D5576 00 (2013)3
