1、Designation: D 4937 96 (Reapproved 2006)e1Standard Test Method forp-Phenylenediamine Antidegradants Purity by GasChromatography1This standard is issued under the fixed designation D 4937; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTESource footnotes were removed editorially in April 2006.1. Scope1.1 This test method covers the determinat
3、ion of the purityof Class I, II, and III p-phenylenediamine (PPD) antidegradantsas described in Classification D 4676 by gas chromatography(GC) detection and area normalization for data reduction.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are
4、 for informationonly.1.3 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-priate safety and health practices and determine the applica-bility of regulatory limitations prior t
5、o use.2. Referenced Documents2.1 ASTM Standards:2D 3853 Terminology Relating to Rubber and RubberLaticesAbbreviations for Chemicals Used in Com-poundingD 4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustriesD 4676 Classification for Ru
6、bber CompoundingMaterialsAntidegradentsE 260 Practice for Packed Column Gas Chromatography2.2 ISO Standard:3ISO 6472 Rubber Compounding IngredientsAbbreviations3. Terminology3.1 Definitions:3.1.1 area normalization, na method of calculating thepercent composition by measuring the area of each observ
7、edpeak and dividing each peak area by the total area. Thisassumes that all peaks are eluted and that each component hasthe same detector response.3.1.2 lot sample, na production sample representative of astandard production unit, normally referred to as the sample.3.1.3 specimen, nthe actual materia
8、l used in the analysis.It must be representative of the lot sample.3.2 AbbreviationsThe following abbreviations are in ac-cordance with Terminology D 3853 and ISO 6472:3.2.1 77PDN,N8bis-(1,4-dimethylpentyl)-p-phenylenediamine.3.2.2 DTPDN,N8-ditolyl-p-phenylenediamine.3.2.3 IPPDN-isopropyl-N8-phenyl-
9、p-phenylenediamine.3.2.4 PPDp-phenylenediamine.3.2.5 6PPDN-(1,3 dimethylbutyl)-N8-phenyl-p-phenylenediamine.4. Summary of Test Method4.1 The analysis is performed by temperature programmedGC utilizing either a packed column (Procedure A) or acapillary column (Procedure B). Quantification is achieved
10、 byarea normalization using a peak integrator or laboratory datasystem.5. Significance and Use5.1 This test method is designed to assess the relative purityof production PPDs. These additives are primarily used asantiozonants for tires and other rubber or polymeric products.5.2 Since the results of
11、this test method are based on areanormalization, it assumes that all components are eluted fromthe column and each component has the same detector re-sponse. Although this is not strictly true, the errors introducedare relatively small and much the same for all samples; thus,they can be ignored sinc
12、e the intent of the test method is toestablish relative purity.5.3 Although trace amounts of “low boilers” are present inproduction samples, they are disguised by the solvent peakwhen using packed columns (Procedure A).1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is
13、 the direct responsibility of Subcommittee D11.11 on Chemical Analysis.Current edition approved March 1, 2006. Published April 2006. Originallyapproved in 1989. Last previous edition approved in 2001 as D 4937 96 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact
14、ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from the American National Standards Institute, 25 W. 43rd St., 4thFloor, New York, NY 10036.1Copyright ASTM International, 100 Ba
15、rr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Interferences6.1 Utilizing the chromatographic conditions prescribedthere are no significant co-eluting peaks; however, degradationof column performance could result in interference problems.Thus, when using the packed
16、column it is essential that thetotal system be capable of 5000 theoretical plates before beingused for this analysis. The evaluation of system efficiency isdescribed in 7.4.7. Apparatus7.1 Gas Chromatograph:7.1.1 Procedure A: Packed ColumnAny high-quality tem-perature programmed gas chromatograph eq
17、uipped with athermal conductivity detector (see Note 1) is sufficient for thisanalysis. Refer to Practice E 260 for general gas chromatogra-phy practices.NOTE 1Although a thermal conductivity detector is recommended, aflame ionization detector can be used if appropriate adjustment is made forflow ra
18、te and specimen size. Since this probably would involve using asmaller diameter column, the adjustment in flow and injection volumeshould be proportional to the cross-sectional area of the column. Aprocedure for this calculation is included at the end of Section 9.7.1.2 Procedure B: Capillary Column
19、A temperature pro-grammable unit with flame ionization detector (FID) equippedfor capillary columns. When utilizing the full capillary col-umns (0.25 mm), a split injection system is required; howevera “cold on-column” injector is preferred for the wide bore(0.53 mm) capillaries. The FID should have
20、 sufficient sensitiv-ity to give a minimum peak height response of 30 V for 0.1mass % of 6PPD when operated at the stated conditions.Background noise at these conditions is not to exceed 3 V.7.2 Gas Chromatographic Columns:7.2.1 Packed Column for Procedure A1.828 m 3 6.35mm (6 ft 314 in.) outside di
21、ameter 3 4 mm (0.16 in.) insidediameter glass columns packed with 10 % methyl silicone fluid(100 %) on 80/100 mesh acid washed and silanized diatomitesupport. The column should be conditioned with a helium flowof approximately 20 cm3/min by programming from ambienttemperature to 350C at the rate of
22、2 to 3C/min and holdingat 350C overnight with the detector disconnected.7.2.2 Capillary Column for Procedure B(1)30m3 0.25mm ID fused silica capillary, internally coated to a filmthickness of 0.25 m (bonded) with methyl silicone; (2)15m 3 0.53 mm fused silica (megabore) capillary with 3.0 mbonded fi
23、lm of 5 % phenyl silicone, HP-5 or equivalent.7.3 Integrator/Data System, capable of determining therelative amount of each component by means of integration ofthe detector output versus time. When using capillary columns(Procedure B) the device must integrate at a sufficiently fastrate so that narr
24、ow peaks (one second peak width) can beaccurately measured.7.4 When using a packed column, a minimum of 5000theoretical plates, as measured from the 6PPD peak, with thechromatographic conditions stated in 9.1 is required for analy-sis. Theoretical plates (TP) are determined by the followingformula:T
25、P 5 5.5 XR!/Y0/5!#2(1)where:X(R) = retention time measured from the injection pointto the apex of the 6PPD peak (adjust theattenuation to keep peak on scale), mm, andY (0.5) = 6PPD band width at half-height, mm.8. Calibration and Standardization8.1 When using the conditions described for Procedure A
26、(packed column), the detector response of 6PPD for injectionsof 500 to 5000 g was found to be somewhat nonlinear (seeX1.3). However, over the more limited range, 750 to 2500 g,the response was nearly linear (see X1.4). As a result, it issuggested that the samples be prepared so that 1250 to 1500 gin
27、jections are made.8.2 Chromatograms from typical specimens run on thepacked columns according to the prescribed procedure aregiven in Appendix X1.9. Procedure9.1 Procedure AChromatographic Conditions:Helium flow rate 50 cm3/minInjection port temperature 300CInitial column temperature 100CHeating rat
28、e 8C/minFinal Temperature 350CDetector temperature 350CDetector: TC attenuation 89.1.1 Integrator/data system parameters are presented inX1.2.9.1.2 Specimen PreparationTo ensure specimen homoge-neity, lot samples of 6PPD should be ground with a mortar andpestle prior to weighing the test unit. In th
29、e case of liquid 6PPDwhere partial crystallization may have occurred resulting infractionation, the lot sample should be melted in a 50 to 60Coven with occasional stirring, prior to weighing the test unit.9.2 Procedure AAnalysis:9.2.1 Weigh 2.5 to 3.0 g specimen (to the nearest milligram)intoa10cm3v
30、olumetric flask, dilute to volume with methyl-ene chloride, and shake well to dissolve.9.2.2 When the instrument has equilibrated at the initialconditions described in 9.1, inject 5.0 mm3(L) of samplesolution and initiate the temperature program and data collec-tion.9.2.3 When the run is complete, i
31、nspect the chromatogramand output data for proper appearance and peak identification(see X1.1).9.2.4 Repeat the run described in 9.2.2 on the same speci-men.NOTE 2Specimen size and carrier gas flow rates should be adjusted inaccordance with the cross-sectional area of the column utilized. Forexample
32、, if a nominal18 in. outside diameter column (1.87 mm insidediameter) is used rather than a14 in. outside column (3.54 mm insidediameter), the adjustment would be as follows: The ratio of cross-sectionalareas is 3.54/1.87 squared, which equals 3.6. Thus, the sample size andhelium carrier flow rate s
33、hould be decreased by this factor; that is, the flowrate of 50/3.6 or 14 cm3/min and sample size to 5/3.6 or 1.4 mm3(L).9.3 Procedure B: Chromatographic ConditionsThe sug-gested operating conditions for the analysis using a capillarycolumn are given in Table 1. Column (1) is for a standardcapillary
34、and Column (2) is for a megabore capillary.D 4937 96 (2006)e129.4 Procedure BSample Analysis:9.4.1 Prepare the sample as in 9.1.2 and the test specimenaccording to Table 1.9.4.2 When the instrument has equilibrated at the initialconditions described in Table 1, inject the indicated amount ofdiluted
35、test specimen and immediately start the recorder,integrator, and column temperature programming sequence.9.4.3 When the run is complete, inspect the chromatogramand output data for proper appearance and peak identification.Typical chromatograms on the 0.53 mm megabore capillary isshown in Figs. X2.1
36、-X2.4 (6PPD) respectively.9.4.4 Repeat the run described in 9.4.2 on the same speci-men.10. Calculation10.1 Calculate the relative area percent of 6PPD and theother identified components as follows:A 5 AC/AT! 3 100 % (2)where:A = area of 6PPD, %,AC= area of component, andAT= total area.11. Report11.
37、1 Report the following information:11.1.1 The combined area of all unidentified peaks aspercent other,11.1.2 All results to the nearest 0.1 %, and11.2 The final report should include proper identification ofthe specimen and the data from the two individual injectionsplus their average.12. Precision
38、and BiasProcedure A12.1 This precision and bias section has been prepared inaccordance with Practice D 4483. Refer to Practice D 4483 forterminology and other statistical details.12.1.1 The precision results in this precision and biassection give an estimate of the precision of this test methodwith
39、the materials (antidegradants) used in the particularinterlaboratory programs as described below. The precisionparameters should not be used for acceptance/rejection testingof any group of materials without documentation that they areapplicable to those particular materials and the specific testingp
40、rotocols that include this test method.12.2 A Type 1 (interlaboratory) precision was evaluated in1987. Both repeatability and reproducibility are short term. Aperiod of a few days separates replicate test results.Atest resultis the mean value, as specified by this test method, obtained ontwo determi
41、nations or measurements of the property or param-eter in question.12.3 Four different materials were used in the interlabora-tory program. These were tested in four laboratories on twodifferent days.12.4 The results of the precision calculations for repeatabil-ity and reproducibility are given in Ta
42、ble 2, in ascending orderof material average or level, for each of the materials evalu-ated.12.5 The precision of this test method may be expressed inthe format of the following statements which use an “appro-priate value” or r, R,(r), or (R), that is, that value to be used indecisions about test re
43、sults (obtained with the test method).TABLE 1 Procedure BChromatographic ConditionsColumn (1) 30 m 3 0.25 mm (2) 15 m 3 0.53 mmStationary Phase bonded methyl silicone bonded 5 % phenylsiliconeFilm thickness 0.25 m 3.0 mCarrier gas (helium) (helium)Linear velocity at 100C 0.34 m/sec NAFlow rate 1.0 c
44、m3/min 30.0 cm3/minHead pressure 60 kPa, gauge (9 psig) NADetector FID FIDDetector Temperature 300C 300CInjection Port Temperature 300C oven trackingHydrogen Flow RateA30 cm3/min 30 cm3/minAir Flow RateA300 cm3/min 300 cm3/minMakeup Gas Nitrogen or Helium Nitrogen or HeliumMakeup Flow RateA29 cm3/mi
45、n 10 cm3/minSplit Ratio 180:1 (no split)Column TemperatureProgramRamp A Ramp BInitial temperature 42C 35C 240CProgram rate 9C/min 15C/min 8C/minFinal temperature 300C 240C 290CTime at finaltemperature22 min 3 min 17 minSample Size 0.4 mm3(L) 1 mm3(L)Solvent methylene chloride methylene chlorideSampl
46、e Concentration 10 mg/cm33 mg/cm3AConsult the manufacturers manual for optimum selection of flow rates ondifferent instruments.TABLE 2 GC Purity of PPDS, Percent (Procedure A)Material AverageWithin LaboratoryABetween LaboratoryASrr (r) SRR (R)M1-6PPD 97.09 0.1651 0.4673 0.481 1.926 5.45 5.61M2-IPPD
47、96.05 0.2792 0.7900 0.822 1.239 3.50 3.65M3-77PD 96.05 0.1121 0.3172 0.330 1.382 3.91 4.07M4-DTPD 94.85 0.2894 0.8191 0.864 2.080 5.88 6.20Pooled valuesB96.01 0.2301 0.6512 0.678 1.6588 4.6943 4.889ASr= repeatability standard deviation.r = repeatability = 2.83 times the square root of the repeatabil
48、ity variance.(r) = repeatability (as a percent of material average).SR= reproducibility standard deviation.R = reproducibility = 2.83 times the square root of the reproducibility variance.(R) = reproducibility (as a percent of material average).BNo values omitted.D 4937 96 (2006)e13The appropriate v
49、alue is that value of r or R associated with amean level in Table 2 closest to the mean level underconsideration at any given time, for any given material, inroutine testing operations.12.6 RepeatabilityThe repeatability, r, of this test methodhas been established as the appropriate value tabulated in Table1. Two single test results, obtained under normal test methodprocedures, that differ by more than this tabulated r (for anygiven level) must be considered as derived from different ornonidentical sample pop
