1、Designation: D7399 08Standard Test Method forDetermination of the Amount of Polypropylene (PP) inPolypropylene/LDPE Mixtures Using InfraredSpectrophotometer (FTIR)1This standard is issued under the fixed designation D7399; the number immediately following the designation indicates the year oforigina
2、l 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 This test method uses an infrared approach for deter-mining the pr
3、esence of polypropylene (PP) physically mixed inwith low density polyethylene usually for recycling purposes.NOTE 1Quantitative determinations require several standard mixturesin the concentration range of interest and well defined baseline anchoringpoints.1.2 This standard does not purport to addre
4、ss all of thesafety concerns, if any, associated with its use. It is theresponsibility 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.NOTE 2There is no known ISO equivalent to this standard.2.
5、 Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD2238 Test Methods forAbsorbance of Polyethylene Due toMethyl Groups at 1378 cm1D5033 Guide for Development ofASTM Standards Relatingto Recycling and Use of Recyc
6、led Plastics (Withdrawn2007)3E131 Terminology Relating to Molecular SpectroscopyE168 Practices for General Techniques of Infrared Quanti-tative AnalysisE932 Practice for Describing and Measuring Performance ofDispersive Infrared SpectrometersE1421 Practice for Describing and Measuring Performanceof
7、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 Metric System3. Terminology3.1 DefinitionsFor definitions of plastics terms used inthis test method, see Terminology standards D
8、883, D1600, andD5033.3.2 TerminologyUnits, symbols, and abbreviations used inthis test method appear in Terminology E131 or IEEE/ASTMSI-10.4. Summary of Test Method4.1 Thin films representing a typical portion of the materialare analyzed with an IR spectrophotometer using two absor-bance bandsone ch
9、aracteristic for polypropylene (PP) andone for low density polyethylene (LDPE). The ratio of thesetwo absorbencies is used to assess the presence of polypropyl-ene.4.2 For quantitative determinations, several standards withknown concentrations of PP in LDPE bracketing the range ofinterest are needed
10、 to develop a calibration curve. Also,baseline placement shall be defined to produce repeatableresults.5. Significance and Use5.1 In recycling PP and LDPE, it is important to the endproduct properties as well as to the processing conditions toknow what the purity of the mixture is. In many cases, it
11、 is vitalto know that the recycled material is reasonably free of acontaminant.6. Interferences6.1 Presence of materials other than PPor LDPE in a samplemight cause error in measurement.6.2 Inhomogeneous sample is known to cause false reading.It is recommended to verify sample homogeneity by measuri
12、ngdifferent areas of the sample.1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.70 on Analytical Methods.Current edition approved Sept. 1, 2008. Published September 2008. DOI:10.1520/D7399-08.2For referenced ASTM standa
13、rds, 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 onwww.astm.org.Copy
14、right ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesNOTICE: This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International (www.astm.org) for the latest information17. Apparatus7.1 Infrared Spect
15、rophotometer, either double beam or aFourier transform (FTIR).7.1.1 Double-Beam Infrared Spectrophotometer, capable ofa4cm-1spectral resolution as defined in Practice E932. Theinstrument shall be capable of scale expansion along thewavelength axis.7.1.2 Fourier Transform Infrared Spectrometer, capab
16、le of 4cm-1resolution. The instrument shall be capable of scaleexpansion along the wavelength axis.Also, see Practice E1421for testing procedures.7.2 Film Mounts, with apertures at least 6 by 27 mm, to holdthe film specimens in the infrared spectrophotometer.NOTE 3Attenuated Total Reflectance (ATR)
17、methodology is accept-able as an alternative to the transmission mode. For best results, sampleshall be tested using the same mode as the calibration curve.8. Hazards8.1 The optical bench of the FTIR spectrometer contains alaser. To avoid eye injury, do not look directly into the laserbeam.9. Proced
18、ure9.1 Sample Preparation:9.1.1 Use film specimens that give absorbencies 1.5 units orless on IR scan. Thickness of approximately 0.025 mm (1 mil)has been found adequate.NOTE 4For samples not available in the proper thickness range, thefilms can be produced on any suitable cast or blown film unit us
19、ingappropriate conditions that will produce films of uniform thickness andappearance.9.2 Spectral Measurements:9.2.1 Place the sample in the infrared spectrophotometer.9.2.2 Set the controls of the infrared spectrophotometer togive a good signal to noise ratio.Aspectral resolution of 4 cm-1and a Bee
20、r-Norton medium or Happ-Genzel apodization func-tion have been found to be appropriate.9.2.3 Record the infrared spectrum from 4000 cm-1to 500cm-1.9.3 Determine the absorbance of bands at 1373 cm-1and1465 cm-1one characteristic for polypropylene (PP) and onefor low density polyethylene (LDPE). Draw
21、baseline between1200 cm-1and 1600 cm-1and use it for both peaks.NOTE 5The 1373 cm-1and 1465 cm-1bands present in both spectra,but, within limits, the ratio of the two can be used for differentiation.NOTE 6There is a valley between these two peaks. If preferred, drawbaseline for individual peak.9.4 S
22、everal standards with known concentrations of PP areneeded to develop a calibration curve. The absorbance ratio of1373 cm-1versus 1465 cm-1is plotted against PPconcentrationfrom which the PP content of the unknown sample is obtained.Use the average of three measurements for calibration curve.(See Fi
23、g. 1)9.5 Measure the absorbance ratio of unknown sample andcalculate the amount of PP from the calibration curve using thesame baseline anchoring points as used for calibration curve.10. Report10.1 Report the following information:10.1.1 Complete identification of material tested includingname, manu
24、facturer, lot number and physical form whensampled.10.1.2 Date of test.10.1.3 Any sample or spectral anomalies observed duringthe measurement.11. Precision and Bias11.1 An unknown sample was measured ten times. Theaverage content of PP is 26.0 % and the standard deviation is1.2 %. The coefficient of
25、 variation is 4.7 %.12. Keywords12.1 infrared spectrophotometer; low density polyethylene;polypropyleneFIG. 1 Example of the Calibration CurveD7399 082ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Use
26、rs 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 committee and must be reviewed every
27、 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 meeting of theresponsible technic
28、al 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 Box C700, West Conshohocken
29、, 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 083
