1、Designation:D427421Standard Test Methods for TestingPolyurethane Raw Materials:Determination of HydroxylNumbers of Polyols1This standard is issued under the fixed designation D4274;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the
2、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.Scope*1.1 These test methods measure the hydroxyl groups inpolyester and polyether polyols containing primary and sec-ondary
3、 hydroxyl groups.They also apply to many otherhydroxyl-containing substances.1.1.1 Test Method AAcetic Anhydride Pressure Bottle,recommended for polyesters.1.1.2 Test Method BPhthalic Anhydride Pressure Bottle,recommended for polyethers and polyesters.1.1.3 Test Method CPhthalic Anhydride Reflux,rec
4、om-mended for polyethers and polyesters.1.1.4 Test Method DImidazoleCatalyzed Phthalic Anhy-dride Pressure Bottle,recommended for polyethers,polyesters,polymer polyols,and amine-initiated polyols.1.1.5 Test Method EImidazole-Catalyzed Pyromellitic Di-anhydride Esterification,recommended for polyols
5、used forflexible and rigid polyurethane foams and urethane elastomers.It is recommended for polyester polyols,polyether polyols,amine-started polyols,and polymer polyols(polyacrylonitrile/copolystyrene-based).1.2 Another ASTM test method for measuring hydroxylgroups is Test Method E222.1.3 The value
6、s stated in SI units are to be regarded as thestandard.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,health,and environmental practices and deter-mine the ap
7、plicability of regulatory limitations prior to use.NOTE1This standard,ISO 14900 and ISO 6796 address the samesubject matter,but differ in technical content.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the D
8、ecision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD1193 Specification for Reagent WaterE180 Pra
9、ctice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals(Withdrawn 2009)3E200 Practice for Preparation,Standardization,and Storageof Standard and Reagent Solutions for Chemical AnalysisE203 Test Method for Water Using Volumetric Karl FischerT
10、itrationE222 Test Methods for Hydroxyl Groups Using AceticAnhydride AcetylationE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE2935 Practice for Evaluating Equivalence of Two TestingProcesses2.2ISO St
11、andard:4ISO 6796 Polyglycols for Industrial UseDetermination ofHydroxyl NumberPhthalic Anhydride EsterificationMethodISO 14900 PlasticsPolyols for Use in the Production ofPolyurethaneDetermination of Hydroxyl Number3.Terminology3.1 DefinitionsTerms used in this standard are defined inaccordance with
12、 Terminology D883,unless otherwise speci-fied.For terms relating to precision and bias and associatedissues,the terms used in this standard are defined in accordancewith Terminology E456.1These test methods are under the jurisdiction of ASTM Committee D20 onPlastics and is the direct responsibility
13、of Subcommittee D20.22 on CellularMaterials-Plastics and Elastomers.Current edition approved July 1,2021.Published July 2021.Originally approvedin 1988.Last previous edition approved in 2016 as D4274-16.DOI:10.1520/D4274-21.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American National Standards Institute(ANSI
15、),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with int
16、ernationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.13.2 Definitions of Terms Specific to This StandardThereare no terms in these test methods that require new or otherthan dictionary definitions.4.Summary of Test Methods4.1 Test Method AThe sample is acetylated with a solutionof acetic anhydride in p