1、Designation: D3677 10 (Reapproved 2015)Standard Test Methods forRubberIdentification by Infrared Spectrophotometry1This standard is issued under the fixed designation D3677; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 These test methods cover rubb
3、er identification and arebased on infrared examination of pyrolysis products (pyrolyz-ates) and films.1.2 These test methods are applicable to rubbers in the rawstate and, when compounded, both in the cured and uncuredstate.1.3 Since it is customary in infrared spectrophotometry touse wavenumbers (c
4、m1) rather than Hertz (Hz), the unit forfrequency in the SI system, the former is employed throughoutthis test method.1.4 This test method assumes that specimens and infraredspectra are prepared and analyzed by experienced personneland that the equipment is operated according to the manufac-turers d
5、irection for optimum performance. No details foroperation of infrared spectrophotometers are included in thistest method.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-p
6、riate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 17.2. Referenced Documents2.1 ASTM Standards:2D297 Test Methods for Rubber ProductsChemical Analy-sisD1418 Practice for Rubber and Rubber
7、 LaticesNomenclatureD3452 Practice for RubberIdentification by Pyrolysis-GasChromatographyE168 Practices for General Techniques of Infrared Quanti-tative Analysis (Withdrawn 2015)33. Significance and Use3.1 For research, development, and quality controlpurposes, it is advantageous to determine the c
8、omposition ofrubbers in cured, compounded products.3.2 This test method provides such composition analysisutilizing an infrared technique.4. Reagents4.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to t
9、he specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determi
10、nation.4.2 Acetone.4.3 Alcohol, ethanol, denatured.4.4 2-Butanone.4.5 Chloroform.4.6 Congo Red Paper.4.7 Diatomaceous Filter AidSome grades are quite unsat-isfactory in that they will not sufficiently absorb carbon black.4.8 1,2-DichlorobenzeneA check on suitability may bemade by evaporating 50 cm3t
11、o dryness and making an infraredspectrum of the residue. Any substantial absorbance at posi-tions near those wavenumbers that will be used for rubberanalysis, indicates that the 1,2-dichlorobenzene is unsuitablefor use.1These test methods are under the jurisdiction of ASTM Committee D11 onRubber and
12、 are the direct responsibility of Subcommittee D11.11 on ChemicalAnalysis.Current edition approved June 1, 2015. Published September 2015. Originallyapproved in 1978. Last previous edition approved in 2010 as D3677 101. DOI:10.1520/D3677-10R15.2For referenced ASTM standards, visit the ASTM website,
13、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.4Reagent Chemicals, American Chem
14、ical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Ph
15、armaceutical Convention, Inc. (USPC), Rockville,MD.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.9 Dry Compressed Air and Nitrogen, in cylinders, orprovided as a laboratory service.4.10 Sodium Sulfate, anhydrous.4.11 Toluene.TEST
16、METHOD A QUALITATIVE ANALYSIS5. Scope5.1 This test method, based on infrared examination ofpyrolysis products (pyrolyzates) and films, will identify therubbers in 6.1 occurring alone or in binary blends in the rangefrom 80 % major component to 20 % minor component.Exceptions to this will be found in
17、 6.2.5.2 This test method is applicable to rubbers in the raw stateand, when compounded, both in the cured and uncured state.5.3 This test method implies that sample preparation andinfrared spectrum are prepared and analyzed by experiencedpersonnel and that the equipment used for the production of t
18、hespectra is operated according to the manufacturers directionsfor optimum performance. No details for operation of infraredspectrophotometers are included in these test methods.6. Field of Application6.1 Infrared examinations of pyrolyzates and films willidentify mixtures of two of the following ty
19、pes of rubbers inthe range from 80 % major component to 20 % minor compo-nent. (See the exceptions in 6.2.)6.1.1 Isoprene Rubbers (see 6.2.1):6.1.1.1 Natural rubber, synthetic polyisoprene, gutta percha,and balata are included.6.1.1.2 Examination of the pyrolyzate will not distinguishbetween the dif
20、ferent forms of polyisoprene.6.1.1.3 Examination of a film will distinguish natural andsynthetic polyisoprene from balata and gutta percha.6.1.2 Styrene-Butadiene Rubbers with Styrene Content ofApproximately 23.5 % Styrene (see 6.2.2):6.1.2.1 For the purpose of this standard, all copolymers ofstyren
21、e and butadiene and their oil-extended forms are in-cluded.6.1.2.2 Examination of the pyrolyzate will not distinguishbetween emulsion and solution polymerized rubbers.6.1.2.3 Examination of films may give some informationabout the monomer ratio and the polymerization system.6.1.3 Acrylonitrile-Butad
22、iene Rubber with AcrylonitrileContent of Approximately 33 %:6.1.3.1 Examination of the pyrolyzate will not measure theratio of acrylonitrile to butadiene.6.1.3.2 Examination of a film may give some informationabout the acrylonitrile content.6.1.4 Chloroprene RubberThis test method will not dis-tingu
23、ish between the different types of chloroprene rubbers.6.1.5 Butyl Rubber This test method will not distinguishbetween butyl rubber and its halogenated forms.6.1.6 Polybutadiene Rubber (High cis):6.1.6.1 Examination of the pyrolyzate will not distinguishbetween polybutadiene rubbers having different
24、 isomer ratios.6.1.6.2 Examination of a film may give some informationabout the monomer ratio.6.1.7 Ethylene-Propylene Rubbers (see 6.2.3)This testmethod will not distinguish between rubbers having differentratios of ethylene to propylene nor between copolymers andterpolymers.6.2 Exceptions to the r
25、ubbers listed in 6.1 are:6.2.1 A blend of natural or synthetic isoprene (20 %) andchloroprene (80 %), or both, may present difficulties, andidentification of the minor component may be achieved onlywhen its content is equal to or more than 30 % in the blend.6.2.2 A blend of butadiene-styrene rubber
26、(80 %) and highcis polybutadiene rubber (20 %) may present difficulties, andidentification of the minor component may only be achievedwhen it is equal to or more than 30 % in the blend.6.2.3 Ethylene-propylene rubber in blends with other rub-bers presents difficulties when its content is in the rang
27、e from20 to 40 %.6.3 In difficult cases, examination of the gaseous products ofpyrolysis by gas chromatography (Practice D3452) may givefurther information.7. Summary of Test Method7.1 Identification from Pyrolyzates:7.1.1 A small quantity of extracted and dried rubber ispyrolyzed in a stream of nit
28、rogen in a test tube held in a smallelectric, thermo-regulated furnace at 450 to 500C, oralternatively, rapidly pyrolyzed in a small test tube held in thehot zone of a gas flame.7.1.2 A test for chlorine is conducted during pyrolysis.7.1.3 A few drops of the pyrolyzate are transferred to a saltplate
29、 and an infrared spectrum recorded over the 4000 to 666cm1region.7.1.4 The rubber is identified by comparison to standardreference spectra and by reference to a table of diagnosticabsorptions (significant absorption frequencies).7.1.5 Each laboratory employing this standard must preparespectra of al
30、l rubbers they might be expected to identify. Thesespectra must be prepared in the same manner and using thesame equipment as will be used for unknown samples.7.2 Identification from Films:7.2.1 A small quantity of extracted and dried rubber isdissolved in 1,2-dichlorobenzene, filtered, and a film c
31、ast on asalt plate. This film is used as in 7.1.4.7.2.2 A small quantity of extracted and dried rubber issubjected to mild thermal degradation at 200 6 5C for a shorttime. The degraded sample is dissolved in trichloroethylenethen chloroform, and a film cast on a salt plate. This film isused as in 7.
32、1.4.D3677 10 (2015)28. Apparatus8.1 Extraction Apparatus:8.1.1 The extraction apparatus used shall be of the generaltype and dimensions shown in Fig. 1.8.2 Test Tubes, small, and other necessary glassware suffi-cient to carry out the test as written.8.3 Pyrolysis Apparatus (Fig. 2)The pyrolysis appa
33、ratusconsists of a glass tube (P) having inward projections toprevent the sample from falling to the bottom of the tube anda lateral condenser tube. The tube (P) has a ground-glassstandard taper (S) which carries a small glass adductor tube. Acollecting tube (T) is placed under the condenser tube. A
34、nelectric, thermoregulated furnace (F) accommodates an alumi-num block (H) with holes for one or more tubes (P).8.4 Capillary Pipets.8.5 Oven, capable of maintaining a temperature of 200 65C for use in 10.2.8.6 Water Bath, for use in 10.2.8.7 Salt Plates, polished (sodium chloride or potassiumbromid
35、e), 4 by 25 mm, to serve as windows for the spectro-photometer.8.8 Infrared Spectrophotometer, High-Resolution Scanningor Fourier Transform, capable of recording a spectrum overthe 4000 to 667 cm1region. (High resolution5requires that thespectral slit width should not exceed 2 cm1over 80 % of thewav
36、enumber range and at no place should it exceed 5 cm1.)Any spectrophotometer complying with these requirementsmay be used. The equipment shall be operated by an experi-enced analyst according to the manufacturers directions foroptimum performance.9. Preparation of Test Portion9.1 Temperature Controll
37、ed Pyrolysis in a Stream of Nitro-gen (Fig. 2; Preferred Method):9.1.1 Prepare the test portion by milling into a thin sheet ona laboratory mill or cutting into cubes about 2 mm wide andwrap approximately 0.5 g in filter paper or nylon cloth. Extractthe wrapped test portion in an extraction cup in a
38、ccordancewith Section 19 of Test Methods D297, for a minimum of 4 hwith methanol, ethanol, or 2-propanol. A vulcanizate may beextracted with acetone or 2-butanone, in addition to the abovealcohols.Alternatively, the rapid reflux procedure may be usedfor1hinaccordance with Section 26 of Test Methods
39、D297.9.1.2 Remove the extracted rubber from the apparatus anddry at 100C until free of solvent. One to two hours is usuallyrequired.9.1.3 Introduce a small amount of anhydrous sodium sulfateinto the collecting tube (T) to absorb water produced duringpyrolysis.9.1.4 Place a strip of moistened Congo r
40、ed paper across themouth of the tube, as a test for chlorine (a change from red toblue).9.1.5 If alternative chlorine determining methods areemployed, this procedure must be suitably modified.9.1.6 Bring the electrical furnace (F) to 450 to 500C andhold at this temperature. This range is recommended
41、 to obtain5High resolution is defined in “Specification for Evaluation of Research QualityAnalysis of Infrared Spectra,” Analytical Chemistry, ANCHA, Vol 47, No. 11, p.94A.FIG. 1 Extraction Apparatus with Glass Condenserand Ground Glass JointF electric, thermoregulated furnaceH aluminum block, bored
42、 to hold tubesP glass tube for sample containerS ground-glass taperT collecting tubeFIG. 2 Temperature Controlled Pyrolysis ApparatusD3677 10 (2015)3fast pyrolysis, without excessive degradation and carboniza-tion. Temperatures below this range should be avoided.9.1.7 Pass a slow stream of nitrogen
43、through the pyrolysistube and introduce the tube into a hole of the aluminum block(H). The nitrogen serves to displace air, prevent oxidation, andfacilitate transfer of the pyrolysis products to the collectingtube (T).9.1.8 Carry on heating to complete distillation, which re-quires approximately 15
44、min.9.1.9 Transfer a few drops of the pyrolyzate from the tube toa sodium chloride or potassium bromide plate, using a capillarypipet.9.1.10 Place a spacer of suitable thickness in position, closethe cell with a second plate of the same material, and mount thecell in the infrared spectrophotometer.9
45、.1.11 Record the spectrum over the wavelength range from4000 to 666 cm1.9.1.12 Spectra should be obtained immediately after pyroly-sis to minimize further change in the pyrolysis products.9.2 Gas Flame Pyrolysis (Alternative Test Method):9.2.1 Prepare the extract, dry2goftest portion (9.1.1 and9.1.2
46、), and place 0.1 to 0.2 g of the test portion in the bottomof a small glass test tube. Place a strip of moistened Congo redpaper across the mouth of the tube. Hold the tube horizontally,and quickly bring the lower end containing the test portion intothe hot zone of a gas burner, so that the rubber i
47、s rapidlypyrolyzed and charring is kept to a minimum. Note any colorchange in the Congo red paper, from red to blue, indicating thepresence of chlorine.9.2.2 Maintain the heating until the pyrolyzate condenses inthe cool end of the tube, withdraw the test tube from the flame,and cool while holding h
48、orizontally.9.2.3 Alternatively, the sample may be placed in a smallglass tube and the end of the tube drawn out to a “retort” shapewith a blast lamp. Pyrolysis is carried out as described in 9.2.1.Care should be taken to keep the delivery end of the pyrolysistube warm enough so that pyrolysis produ
49、cts do not condenseand block the opening, causing the tube to explode. Thecondensate can be collected in a small test tube containinganhydrous sodium sulfate to remove moisture. Proceed as in9.1.9 9.1.12.9.2.4 If alternative chlorine detecting methods areemployed, this procedure must be suitably modified.10. Sample Preparation for Films10.1 Dissolution for Vulcanizates:10.1.1 Prepare a test portion in accordance with 9.1.1 and9.1.2.10.1.2 Pyrolyze and test for chlorine in accordance with9.1.4 and 9.1.5 or 9.2.1 9.2.4.10.1.3 Place1goftheprepared rubber
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