1、Designation: D 4827 03Standard Test Method forDetermining the Unreacted Monomer Content of LatexesUsing Capillary Column Gas Chromatography1This standard is issued under the fixed designation D 4827; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase of revision, 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.1. Scope1.1 This test method is for the determination of the unre-acted monomer content of acrylic l
3、atexes. Monomers that havebeen successfully determined by this procedure include n-butylmethacrylate, n-butyl acrylate, styrene, and methyl methacry-late. The determination of other monomers has not beenevaluated, but this test method is believed to be applicable. Theestablished working range of thi
4、s test method is from 100 to1000 g/g, but there is no reason to believe it will not workoutside of this range, provided that appropriate dilutions andadjustments in specimen size are made.1.2 The unreacted monomer in acrylic latexes is expected tochange with time and environmental factors. This time
5、 depen-dence of the determination may be seen as an artificially largedeviation of results, making the test method mostly applicablefor in-house quality control, where sampling and analysisconditions can be better controlled.1.3 The values stated in SI units are to be regarded as thestandard. The va
6、lues given in parentheses are for informationonly.1.4 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 r
7、egulatory limitations prior to use. For specific hazardstatements, see Section 7.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent Water3. Summary of Test Method3.1 A suitable aliquot of the latex is internally standardizedwith isobutyl acrylate, diluted with water, and the
8、n injectedonto a capillary gas chromatographic column containing astationary phase that separates the internal standard and mono-mers in question from each other and from other volatilecompounds.4. Significance and Use4.1 Excessive amounts of unreacted monomer may causeconcerns relating to toxicity
9、and odor. This test method isdesigned to measure the unreacted monomer content of latexes.The results may be used to monitor the extent of polymeriza-tion during manufacture, as well as to establish maximumunreacted monomer content for regulatory purposes.5. Apparatus5.1 Gas ChromatographAny gas-liq
10、uid chromatographicinstrument having a flame ionization detector and lineartemperature programming and a capillary column inlet capableof split operation. The split liner should be constructed of glassand be replaced or cleaned as needed. On-column injection intoa wide bore capillary column was not
11、evaluated but is expectedto also be satisfactory for this procedure.5.2 Column30-m by 0.25-mm inside diameter fused silicacoated witha1mthick film of a phenyl methyl siliconepolymer. A bonded phase is preferred. Other columns havingequivalent or superior performance may also be used.5.3 RecorderA re
12、cording potentiometer with a full-scaledeflection of 10 mV, a full-scale response time of2sorless,and a maximum noise level of 60.03 % of full scale. The useof a recording integrator or other data-handling device ispreferred.5.4 Liquid Charging DevicesA microsyringe, 1.0-L ca-pacity, or an automatic
13、 liquid sampling device using a suitablesyringe and appropriate change in split ratio.5.5 Dropper Pipettes, glass, disposable.5.6 Vials, approximately 7 mL capacity, with caps. Open topscrew-cap vials fitted with PTFE/silicone septa are preferred.5.7 Autosampler Vials, 2 mL capacity (optional).1This
14、 test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved Dec. 1, 2003. Published January 2004. Originallyap
15、proved in 1988. Last previous edition approved in 1993 as D 4827 93 (1998).2For 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
16、 ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.8 Analytical Balance, accurate to 0.1 mg.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended t
17、hatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without le
18、ssening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type II of Specification D 1193.6.3 Carrier GasHelium of 99.995 % or higher purity.High purity nitrogen may also be used.6.4 Acetone.6.5 I
19、sobutyl Acrylate (internal standard), 99 + % pure.NOTE 1Isobutyl acrylate was found to be a suitable internal standard,but any other monomer not found in the sample may be substituted. Theinternal standard chosen should yield a clear chromatographic separation,and should be free of interferences.6.6
20、 Monomers of Interest, 99+ % pure.6.7 Methanol.7. Hazards7.1 Acrylic and methacrylic monomers are considered haz-ardous. All sample preparations should be done in a wellventilated area, such as a fume hood.8. Preparation of Apparatus8.1 Column ConditioningAttach one end of the column tothe inlet sid
21、e of the instrument leaving the exit end of thecolumn disconnected. This prevents the contamination of thedetector due to column bleed. Set the helium flow rate at 0.5mL/min (approximately equivalent to a linear velocity of 20cm/s) and purge the column at 220C for 1 h.8.2 After conditioning, connect
22、 the exit end of the column tothe detector and establish the operating conditions required togive the desired separation (see Table 1). Allow sufficient timefor the instrument to reach equilibrium as indicated by a stablebaseline.8.3 Control the detector temperature so that it is constant towithin 1
23、C without thermostat cycling which causes an unevenbaseline. Adjust the carrier gas flow rate to a constant value.9. Calibration9.1 Determine the retention time of each component ex-pected to be present by injecting small amounts either sepa-rately or in known mixtures. Retention times should bedete
24、rmined each day that the test method is used.9.2 StandardizationDetermine in duplicate the relativeresponse of the monomers of interest to the isobutyl acrylateinternal standard as follows:9.2.1 Weigh to within 0.1 mg about 0.05 g of isobutylacrylate and each monomer of interest into a vial (see 5.6
25、).Weigh approximately5gofacetone into the vial and mix well.9.2.2 Weigh approximately 0.05 g of the solution preparedin 9.2.1 into another vial, add approximately5gofacetone,and mix well.9.2.3 Inject a 0.5-L aliquot of the solution from 9.2.2 ontothe column and record the chromatogram. The elution o
26、rder foracetone and each of the monomers using the conditions givenin Table 1 is shown in Fig. 1.9.2.4 Measure the peak areas of the individual componentsand calculate the relative response factor, RF, for the mono-mers of interest as follows:3Reagent Chemicals, American Chemical Society Specificati
27、ons, 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. Pharmacopeial Convention,
28、Inc. (USPC), Rockville,MD.TABLE 1 Instrument ConditionsDetector flame ionizationAirflow, mL/min 240AHydrogen flow, mL/minMakeup gasHelium3030Column:BLength, m 30Inside diameter, mm 0.25Film thickness, m 1Carrier gas heliumFlow rate 0.5 mL/minTemperatures:Injection port, C 220Detector block, C 250Col
29、umn:Initial, C 60Hold time, min 4Program rate, C/min 8Final, C 200 (or higher as needed)Final hold, min 10 (or longer)Injection volume, L 0.5Split ratio 20:1ASet at recommended flow according to the instrument manufacturer.BCross-linked 50 % phenyl 50 % methyl silicone. A column of equivalent orbett
30、er performance may also be used.FIG. 1 Typical ChromatogramD4827032RF 5 W13 As!/Ws3 A1! (1)where:RF = relative response factor for each monomer,A1= peak area produced by the monomer,As= peak area produced by the internal standard,W1= weight of monomer used for calibration (see 9.2.1),g, andWs= weigh
31、t of internal standard (see 9.2.1), g.10. Procedure10.1 If the composition of the latex is not known or if theapproximate level of monomers in the latex is not known, apreliminary analysis must be performed by diluting approxi-mately 0.5 g of latex with approximately5gofwater andinjecting a 0.5 L al
32、iquot into the chromatographic column.Using the same conditions as for standardization, record thepeaks of all components at attentuation settings that providemaximum peak heights. Use the relative retention times toidentify the monomers present. If the specimen has a compo-nent eluting at the same
33、retention time as isobutyl acrylate,choose a different internal standard (see Note 1).10.2 Prepare a dilute solution of the internal standard byweighing to 0.1 mg about 0.05 g of isobutyl acrylate and5gofacetone into a septum vial. Take care to minimize losses due toevaporation. Prepare this solutio
34、n fresh each day that the testmethod is used.10.3 Weigh to within 0.1 mg an appropriate amount ofsample into a septum vial using Table 2 as a guide to specimensize. Also weigh to within 0.1 mg 50 mg of the dilute solutionprepared in 10.2 into the vial. Add about 3 to5gofwater oracetone. Shake the vi
35、als on a wrist action shaker or othersuitable device for 15 min.NOTE 2The viscosity of a number of latexes increases upon theaddition of an organic solvent. If acetone (or another organic solvent) isfound to be compatible with the specimen, it should be used as the diluentinstead of water. It should
36、 be kept in mind that some organic solvents mayinterfere with the chromatographic separation. A 50:50 water/methanolmixture was also found to work well as a diluent for a number ofspecimens.10.4 Inject 0.5 L of the solution prepared in 10.3 andrecord the chromatogram using the conditions given in 10
37、.1.Measure the peak areas (Note 3) of the internal standard andrelevant monomers, multiplying each area by the appropriateattenuation factor to express the peak areas on a common basis.NOTE 3Peak areas may be determined by any method that meets theprecision requirements given in Section 12. Electron
38、ic integration isrecommended for best results.10.5 Repeat 10.3 and 10.4 and calculate the mean values.11. Calculations11.1 Calculate the weight of the internal standard present inthe diluted specimen (see 10.3) as follows:W45 W5/W6!W7(2)where:W4= weight of internal standard in diluted specimenprepar
39、ed in 10.3, g,W5= weight of internal standard used to prepare solutionin 10.2, g,W6= weight of acetone plus weight of internal standardused to prepare solution in 10.2, g, andW7= weight of the dilute internal standard solution in 10.2added to the specimen in 10.3, g.11.2 Calculate the concentration
40、of each monomer presentin the latex specimen from the results obtained in 10.5 asfollows:C 5 A33 W43 RF!/W83 A4!# 3 106(3)where:A3= peak area produced by the monomer,A4= peak area produced by the internal standard,C = concentration of unreacted monomer, g/g,RF = relative response factor for each mon
41、omer calculatedin 9.2.4,W4= weight of internal standard calculated in 11.1, g, andW8= weight of specimen prepared in 10.3, g.12. Precision and Bias412.1 In an interlaboratory study of this test method by fivelaboratories using four specimens, each containing variableconcentrations of four different
42、monomers, the followingduplicates, repeatability, and reproducibility coefficients ofvariation were obtained for each monomer:Precision, %Monomer DuplicatesRepeatability(SingleLaboratory)Reproducibility(BetweenLaboratory)Methyl methacrylate (MMA) 11.7 34.3 86.2n-Butyl acrylate (BA) 13.3 21.7 49.2But
43、yl methacrylate (BMA) 14.5 33.5 96.5Styrene (STY) 11.3 30.5 71.5NOTE 4Variation in results may be due to the changing compositionof the specimens used for the study. This precision statement should onlybe used as a guide since it only represents the magnitude of variation thatis possible, which will
44、 vary with time depending on the latex and theparticular monomers being determined.12.2 Bias cannot be determined because there are no ac-cepted standards for unreacted monomer content of latexes.13. Keywords13.1 gas chromatography; gas chromatography (capillarycolumn); latex paints; latex vehicles;
45、 monomer (unreacted);4Supporting data is available from ASTM International Headquarters. RequestRR:D01-1059.TABLE 2 Suggested DilutionsNOTE 1This table is to be used only as a guide. If the monomerconcentrations are outside the range given, appropriate adjustments mustbe made in terms of specimen si
46、ze, dilution, and amount of internalstandard added.Level of Unreacted Mono-mer Expected, g/gSpecimen Size, g Diluent, g250 2 3500 1 4750 0.7 4.31000 0.5 4.5D4827033unreacted monomer contentASTM International takes no position respecting the validity of any patent rights asserted in connection with a
47、ny item mentionedin 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 technica
48、l committee 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
49、at a meeting 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 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.
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