ASTM_D_6979_-_13.pdf

Designation:D697913Standard Test Method forPolyurethane Raw Materials:Determination of Basicity inPolyols,Expressed as Percent Nitrogen1This standard is issued under the fixed designation D6979;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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 measures the basic constituents inpolyols that are soluble in glacial acetic acid and reactive withperchloric acid.Samples containing 0.3 10%nitrogen havebeen evaluated by this method.This test method is applicableto polyether polyols and polyether polyol blends that are usedin urethane reactions.(See Note 1.)1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 to use.NOTE1This standard is equivalent to ISO 25761:082.Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals(Withdrawn 2009)3E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod see Terminology D883.3.2 Definitions of Terms Specific to This Standard:3.2.1 percent nitrogenthe quantity of perchloric acid-titratable base,expressed as a weight percentage of nitrogen ina sample.4.Summary of Test Method4.1 The sample is dissolved in glacial acetic acid.Theresulting single-phase solution is titrated at room temperatureto a potentiometric end point with a standardized solution ofperchloric acid in acetic acid.Results are reported as percentnitrogen.5.Significance and Use5.1 This test method is suitable for quality control,as aspecification test,and for research.The results are measures ofbatch-to-batch uniformity and are useful in estimating reactiv-ity.5.1.1 The percent nitrogen can be used to characterize apolyol or indicate amounts of certain components in a polyolblend.5.1.2 It is permissible to also express the results in equiva-lents of base per gram of sample,if desired.6.Apparatus6.1 Potentiometric Automatic Titrator6.2 Autotitrator Buret with Dosing Device,20-mL6.3 pH Glass Electrode and Reference Electrode or aCombination Glass Electrode6.4 Analytical Balances,capable of weighing to the nearest0.01g and 0.0001 g6.5 Magnetic Stirrer/Hotplate7.Reagents and Materials7.1 Purity of ReagentsUse reagent-grade chemicals in alltests.Unless otherwise indicated,it is intended that all reagentsconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society where such1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.22 on Cellular Materials-Plastics and Elastomers.Current edition approved Nov.1,2013.Published November 2013.Originallyapproved in 2003.Last previous edition approved in 2008 as D6979-08.DOI:10.1520/D6979-13.2For 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 ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 specifications are available.4It is permissible to use othergrades provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Acetic Acid,Glacial7.3 Acetic Anhydride7.4 Perchloric Acid,(70%nominal)7.5 Perchloric acid in Acetic Acid(0.10 N)Prepare 0.10 Nperchloric acid in acetic acid.For example,in a 1000-mLvolumetric flask dissolve 8.7 mL of perchloric acid in 500 mLof glacial acetic acid;add 25 mL of acetic anhydride and diluteto volume with glacial acetic acid.NOTE2Perchloric Acidis extremely irritating to the skin,eyes andmucous membrane;highly toxic via oral and inhalation routes;and canform explosive mixtures when mixed with carbonaceous material orallowed to dry.Concentrated material shall only be used in a hoodapproved for perchloric acid use.Skin contactwash with soap and water.Eye contactflush with copious amounts of water for 15 minutes.Inhalation-move victim to an uncontaminated area.Ingestiondo notinduce vomiting.For all exposures seek professional medical advice.8.Procedure8.1 Weigh the appropriate