1、Designation:D505490(Reapproved 2014)Standard Test Method forRubber ChemicalsDiphenyl Guanidine(DPG)and Di-o-tolyl-guanidine(DOTG)Assay1This standard is issued under the fixed designation D5054;the number immediately following the designation indicates the year oforiginal adoption or,in the case of r
2、evision,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 covers the determination of assay ofdiphenyl guanidine(DPG)and di-o-tolyl-guanidine(DO
3、TG).It is based on a visual titration of DPG or DOTG withhydrochloric acid(HCl).1.2 The assay is determined as mass percent.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of
4、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.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reage
5、nt WaterD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3.Summary of Test Method3.1 DPG or DOTG is dissolved in methanol and titratedwith HCl solution using bromophenol blue indicator.4.Significance and Use4.1 DPG and DOTG are us
6、ed for rubber and latex vulcani-zation acceleration.The amount of DPG or DOTG may be ofimportance in predicting performance in rubber compoundsand for raw material purchase and control.4.2 This test method may be used as a quality control tooland for research and development work.5.Interferences5.1
7、Alkaline contaminants that are titratable with HCl inter-fere with the results.6.Apparatus6.1 Erlenmeyer Flask,200-cm3.6.2 Graduated Cylinder,25-cm3.6.3 Magnetic Stirrer.6.4 Analytical Balance,having a sensitivity of 60.1 mg.6.5 Buret,50-cm3capacity.7.Reagents and Materials7.1 Purity of ReagentsReag
8、ent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall 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
9、 ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water as definedby Types I,II,or III of Specification D1193.7.3 Methan
10、ol,analytical reagent.7.4 Hydrochloric Acid(HCl)(0.1 N).7.5 Bromophenol Blue Indicator Solution(0.4 g/cm3)Dissolve 0.4 g bromophenol blue in 1000 cm3methanol.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.11 on Chemical
11、 Analysis.Current edition approved Aug.1,2014.Published November 2014.Originallyapproved in 1990.Last previous edition approved in 2009 as D5054 90(2009).DOI:10.1520/D5054-90R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For
12、Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For Suggestions on the testing of reagents notlisted by the American Chemical Society,see
13、 Annual Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 8.Sampling8
14、.1 Depending upon the purpose of the testing,samplingshall be at the discretion of the analyst to obtain as represen-tative a sample as possible of the lot to be tested.9.Procedure9.1 Accurately weigh about 1.0 g of the test specimen to thenearest 0.1 mg and carefully transfer it to a 200-cm3Erlen-m
15、eyer flask.9.2 Using a graduated cylinder,dissolve the specimen byadding 25 cm3of methanol.9.3 With stirring,add 5 drops of bromophenol blue indicatorsolution.9.4 Titrate with 0.1 N HCl solution.The color change at theend point is from blue-violet to green.10.Calculation10.1 Calculate the percent DP
16、G,A,as follows:A 5V 3N 30.2112W3100(1)where:V=volume of 0.1 N HCl used,for titration of thesample,cm3,N=normality of the HCl solution,W=sample used,g,and0.2112=millimole mass of DPG.10.2 Calculate the percent DOTG,B,as follows:B 5V 3N 30.2393W3100(2)where:0.2393=millimole mass of DOTG.11.Report11.1 Report the following information:11.1.1 Proper identification of the sample,and11.1.2 Results obtained from the two individual determina-tions and their average,reported to the nearest 0.1%.12.Precisi
