1、Designation: D3452 06 (Reapproved 2012)Standard Practice forRubberIdentification by Pyrolysis-Gas Chromatography1This standard is issued under the fixed designation D3452; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.PART 1. IDENTIFICATION OF SINGLE POLYMERS1. Scop
3、e1.1 This practice covers the identification of polymers inraw rubbers, and cured and uncured compounds, based on asingle polymer, by the gas chromatographic patterns of theirpyrolysis products (pyrograms). Implementation of this guidepresupposes a working knowledge of the principles and tech-niques
4、 of gas chromatography, sufficient to carry out thispractice and to interpret the results correctly.21.2 This practice will identify the following polymers:1.2.1 Polyisoprene of natural or synthetic origin,1.2.2 Butadiene-styrene copolymers,1.2.3 Polybutadiene,1.2.4 Polychloroprene,1.2.5 Butadiene-a
5、crylonitrile copolymers,1.2.6 Ethylene-propylene copolymers and relatedterpolymers, and1.2.7 Isobutene-isoprene copolymers.1.3 This practice will not differentiate the following poly-mers:1.3.1 Natural polyisoprene from synthetic polyisoprene.1.3.2 Butadiene-styrene copolymers produced by solutionan
6、d emulsion polymerization. It is sometimes possible todistinguish butadiene-styrene copolymers containing differentamounts of styrene as well as random polymers from blockpolymers.1.3.3 Polybutadiene with different microstructures.1.3.4 Different types of polychloroprenes.1.3.5 Butadiene-acrylonitri
7、le copolymers with differentmonomer ratios.1.3.6 Ethylene-propylene copolymers with different mono-mer ratios, as well as the copolymers from the related terpoly-mers.1.3.7 Isobutene-isoprene copolymers (butyl rubbers) fromhalogenated butyl rubbers.1.3.8 Polyisoprene containing different amounts of
8、cis-transisomers.1.3.9 The practice does not identify ebonite or hard rubbers.1.4 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its
9、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.2. Referenced Documents2.1 ASTM Standards:3D297 Test Methods for Rubber ProductsChemical Analy-sisE260 Practice for
10、Packed Column Gas ChromatographyE355 Practice for Gas Chromatography Terms and Relation-ships3. Significance and Use3.1 For research, development, and quality controlpurposes, it is advantageous to determine the composition ofrubbers in cured, compounded products.3.2 This practice provides such comp
11、osition analysis, uti-lizing a gas chromatograph and pyrolysis products from rubberdecomposition.4. Principle of the Practice4.1 This practice is based upon comparison of the gaschromatographic pattern of the pyrolysis products of a known1This practice is under the jurisdiction of ASTM Committee D11
12、 on Rubber andis the direct responsibility of Subcommittee D11.11 on Chemical Analysis.Current edition approved Aug. 1, 2012. Published May 2013. Originallyapproved in 1975. Last previous edition approved in 2006 as D3452 06. DOI:10.1520/D3452-06R12.2Definitions of terms and general directions for t
13、he use of gas chromatographymay be found in Practices E355 and E260.3For referenced 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 w
14、ebsite.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1rubber with an unknown rubber. The results of this separationwill hereafter be referred to as the pyrogram.4.2 The pyrogram of the known rubber is filed for futurereference. The p
15、yrogram of the unknown rubber is compared tothis for identification.4.3 The success of the method depends upon examining theknown and unknown rubbers under exactly the same experi-mental conditions.4.4 The qualitative composition of the pyrolysis productsdepend upon the type of polymer being studied
16、.4.5 The quantitative composition of the pyrolysis productsmay be affected by the degree of cure, and recipe used, etc., butthe most important factor is the type of pyrolysis device.5. Apparatus5.1 Pyrolysis DevicesThe applicability of this practice hasbeen checked on the following types:5.1.1 Quart
17、z Tubes, electrically heated at a prefixed tem-perature. The volatile products enter the chromatographthrough heated tubing.5.1.2 Platinum Filaments, electrically heated. Pyrolysis iscarried out within the chromatograph inlet and immediatelyswept into the column by the carrier gas.5.1.3 Small Coils
18、of Ferromagnetic Wire, heated to theCurie point temperature. The volatile products enter the gaschromatograph through heated tubing.5.2 Gas ChromatographThe applicability of this practicehas been checked on a wide variety of gas chromatographs,employing both flame ionization and thermal conductivity
19、detectors. Any commercially available instrument is satisfac-tory. Dual-column operation and temperature programming isstrongly recommended, but not mandatory.5.3 Gas Chromatographic ColumnsThe applicability ofthis practice has been checked on a wide variety of columnlengths, diameters, supports, an
20、d liquid phases. The onlyrequisite is that there be sharp separation between the follow-ing: isobutene, butadiene, isoprene, vinylcyclohexene, styrene,and dipentene.5.4 Carrier GasThe applicability of this practice has beenchecked with both helium and nitrogen as the carrier gas. Bothare satisfactor
21、y.6. Sample Size6.1 For thermal conductivity detection and electricallyheated platinum filaments, a sample size of approximately3 mg has been found satisfactory. This could be increased ordecreased depending on the composition of the sample and thecapacity of the probe.6.2 For flame ionization and e
22、ither Curie point apparatus orelectrically heated platinum filaments, a sample size rangingfrom 0.2 to 2.0 mg has been found satisfactory.7. Procedure7.1 ExtractionAlthough not mandatory, some benefitsmay be obtained from extraction of the sample according toTest Methods D297, Sections 18 and 25. If
23、 the sample has beenextracted prior to obtaining the pyrogram, the known must alsobe extracted.7.2 PyrolysisThe following conditions apply to the threetypes of pyrolysis devices in 5.1:7.2.1 Quartz Tubes (5.1.1)Place 1 to 5 mg of sample in asmall quartz or porcelain boat in the cold part of the pyro
24、lysistube. Stopper the tube and flush with carrier gas. Transfer theboat to the hot part of the tube, maintained at 500 to 800C.Length of the time depends upon the pyrolysis device;however, time and temperature must be kept constant. Tominimize condensation, convey the volatile pyrolysis productsint
25、o the gas chromatograph through tubing heated to a known,fixed temperature, but slightly higher than the gas chromato-graph inlet. Record the pyrogram.7.2.2 Electrically Heated Platinum Filaments(5.1.2)Place the required amount of sample in the pyrolysisprobe. Insert it into the injection port of th
26、e gas chromatographand allow the base line to stabilize. Energize the probe, usingthe procedure recommended by the manufacturer of the unit toobtain temperatures of 800 to 1200C.7.2.3 Curie Point Apparatus (5.1.3)Place the requiredamount of sample in the coils of ferromagnetic wire or wrapthe wire s
27、ecurely around the required amount of sample andpyrolyze according to the manufacturers directions for properuse of the unit. Energize the apparatus to obtain the requiredtemperature of 550 to 650C (depending on the composition ofthe alloy used for the wire) and introduce the pyrolysisproducts into
28、the gas chromatograph. Record the pyrogram.7.3 Separation of the Volatile Pyrolysis ComponentsAsstated in 5.3, a wide variety of columns may be used. As anexample, the following describes the separation of volatilepyrolysis components by means of suitable columns. Analysisof the products of polyisop
29、rene pyrolysis are used in thisexample. In all cases, equivalent materials may be used.7.3.1 Polar Liquid PhaseStainless steel tubing, 4 to 6 mlong, with an outside diameter of 3.2 mm (18 in.), packed with10 to 20 % di(2-ethylhexyl)sebacate on a 150 to 180-mdiatomaceous silica support.4Carrier gas f
30、low of 0.2 to0.3 cm3/s. Inlet and detector temperature at 170C. Oventemperature 50C isothermal until isoprene is completelyeluted, then program at 20 to 40C/min to 150C and maintainat this temperature until the dipentene is eluted.7.3.2 Non-Polar Liquid PhaseStainless steel tubing, 3 mlong, with an
31、outside diameter of 3.2 mm (18 in.), packed with10 % high vacuum grease on a 150 to 180-m diatomaceoussilica support. Carrier gas flow of 0.12 to 0.83 cm3/s. Inlettemperature of 170 to 200C. Oven temperature at 50Cisothermal for 3 min or until isoprene is eluted, then raise thetemperature to 130 to
32、150C at 4 to 6C/min. Maintain at thehigher temperature until the dipentene is eluted.4The sole source of supply of diatomaceous silica (Chromosorb P) known to thecommittee at this time is Johns-Manville Products Corp., Celite Div., 22 E. 40th St.,NY, NY 10016. If you are aware of alternative supplie
33、rs, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.D3452 06 (2012)28. Rubber Identification (Interpretation of the Pyrogram)8.1 Each rubber type shows a distin
34、ctive pyrogram, underthe same pyrolysis and gas chromatographic conditions.8.2 Identification is achieved by comparing the pyrogram ofthe sample rubber (unknown) to the pyrogram of the knownrubber, under exactly the same operating conditions.8.3 Some rubbers produce very characteristic hydrocarbonsa
35、nd their identification is relatively easy. Examples of this typeare:8.3.1 Polyisoprene rubbers, which yield mainly isopreneand dipentene.8.3.2 Butadiene-styrene copolymers, which yield mainlybutadiene, vinyl cyclohexene, and styrene.8.3.3 Polybutadiene rubbers, which yield mainly butadieneand vinyl
36、 cyclohexene.8.3.4 Isobutene-isoprene copolymers, which yield mainlyisobutylene.8.4 Some rubbers do not yield very characteristic hydrocar-bons. Careful inspection of the pyrogram is required. Supple-mentary tests, such as those for halogen and nitrogen may bean aid to more definite identification.8
37、.5 It is recommended that, in addition to maintaining alibrary of pyrograms, the analyst compare the unknown samplewith a known, which appears most like his unknown, at thetime of analysis. In this manner, slight variations in operatingparameters, which might influence the pyrogram, might beavoided.
38、9. Precision and Bias9.1 No statement is made about either precision or bias forPractice D3452 since this practice is intended primarily for theidentification of polymers and their relative ratios and not theabsolute levels of the polymers in the compounds beingstudied.PART 2. IDENTIFICATION OF BLEN
39、DS OF POLYMERS10. Scope10.1 This practice is a guide to the identification of blendsof rubbers in the raw, vulcanized, and unvulcanized state by thegas chromatographic patterns of pyrolysis products (pyro-grams). Implementation of this guide presupposes a workingknowledge of the principles and techn
40、iques of gaschromatography, sufficient to carry out the practice, as written,and to interpret the results correctly.10.2 Two methods are described, depending upon the natureof the blend.10.2.1 Method AThis method is used when styrene-butadiene copolymers are absent. The absence of the styrenepeak, i
41、n a preliminary pyrogram, indicates this type of blend.Method A will identify blends of the following:10.2.1.1 Polyisoprene of natural or synthetic origin,10.2.1.2 Butadiene,10.2.1.3 Isobutene-isoprene copolymers, and10.2.1.4 Halogenated isobutene-isoprene rubbers.10.2.2 Method BThis method is used
42、when butadiene-styrene copolymers are present. The presence of the styrenepeak, in a preliminary pyrogram, indicates this type of blend.The method fails if other styrene polymers or copolymers orunextractable styrene-containing resins are present. Method Bis particularly suitable for the identificat
43、ion of polybutadiene inblends with styrene-butadiene copolymers. If the presence ofpolybutadiene in the unknown rubber can be excluded, useMethod A. Method B will identify butadiene-styrene copoly-mers with blends of the following:10.2.2.1 Polyisoprene of natural or synthetic origin,10.2.2.2 Butadie
44、ne, and10.2.2.3 Isobutene-isoprene copolymers and halogenatedisobutene-isoprene rubbers.10.3 Methods A and B will not differentiate the following inblends:10.3.1 Natural polyisoprene from synthetic polyisoprene,10.3.2 Polybutadiene containing different microstruc-tures,10.3.3 Isobutene-isoprene copo
45、lymers and their related ha-logenated rubbers, and10.3.4 Styrene-butadiene copolymers with different mono-mer ratios or different microstructures.11. Referenced Document11.1 See Section 2.12. Significance and Use12.1 See Section 3.13. Principle of the Practice13.1 See Section 4 in addition to the fo
46、llowing:13.1.1 Method AThis method is based upon the identifi-cation of the characteristic hydrocarbon in the pyrogram of theunknown rubber. The identification of the characteristic hydro-carbon is achieved by comparison of retention times under thesame chromatographic conditions for a known rubber
47、as for anunknown rubber. These retention times can be obtained frompyrograms of known rubbers or by direct injection of the purehydrocarbon into the chromatograph.13.1.2 Method BThis method is based upon the identifi-cation of the peaks of vinylcyclohexene and styrene and theirretention times, as in
48、 Method A. Identification of the butadienepeaks is useful but not strictly necessary.13.2 The success of Method A or B depends upon examin-ing the unknown rubber under exactly the same gas chromato-graphic conditions as were used for preparation of the calibra-tion tables of Section 16.14. Apparatus
49、14.1 See Section 5 in addition to the following:D3452 06 (2012)314.1.1 All the devices in accordance with 5.1 may be usedin Part 2, but the Curie point device is especially recommendedwhen Method B is used.14.2 See 5.2. Dual-column operation and temperature pro-gramming is strongly recommended, especially when MethodB is used. Some means of integration is strongly recommendedbut not mandatory.14.3 See 5.4. Nitrogen is the preferred carrier gas when theCurie point device is used. It should not be used with a thermalconductivity detector.15. Procedu
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