1、Designation:D740915(Reapproved 2020)Standard Test Method forCarboxyl End Group Content of Polyethylene Terephthalate(PET)Yarns1This standard is issued under the fixed designation D7409;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,
2、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 procedure is based significantly on the GRIGG7 test procedure,Carboxyl End Group Content of Polyeth-y
3、lene Terephthalate(PET)Yarns.1.2 This test method is used to determine the concentration,in mmol/kg,of carboxyl end groups(CEG)found in poly(eth-ylene terephthalate)(PET)yarns by titration.1.3 This test is applicable to geogrid yarns that are madefrom PET resin.NOTE1This test is also applicable to h
4、igh-strength geotextile yarnsthat are made from PET and are used in reinforcement applications.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns,if any,ass
5、ociated 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 applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally reco
6、gnized principles on standard-ization established in the Decision 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:2D123 Terminology Relatin
7、g to Textiles3.Terminology3.1 Definitions:3.1.1 automatic titration,na titration method in which amachine is used that automatically dispenses small volumes ofthe titrant and monitors the pH or the electrochemical potentialof the solution.3.1.2carboxyl end groups(CEG),nnon-reacted carbox-ylic acid g
8、roups of terephthalic acid located at either end of apolymer chain.3.1.3 colorimetric titration,na titration method that moni-tors the change in color of the solution as the titration proceeds.A chemical indicator sensitive to pH is added to create thecolor change.3.1.4 fibers,na generic term for an
9、y one of the varioustypes of material that form the basic structure of a geogrid(orgeotextile),which are characterized by having a length at least100 times its diameter.3.1.5 filaments,na continuous fiber of extremely longlength.3.1.6 potentiometric titration,na titration method thatmonitors the cha
10、nge in electrochemical potential,expressed asmV,of the solution as the titration proceeds.3.1.7 titration,ntitration is a standard laboratory methodof quantitative chemical analysis which can be used to deter-mine the concentration of a known reactant.Typically,thereaction is a neutralization reacti
11、on between an acid and a base.3.1.8 yarns,na generic term for a continuous strand offibers,filaments,or material in a form suitable for knitting,weaving,or otherwise intertwining to form a textile relatedgeogrid(or geotextile).4.Summary of Test Method4.1 This method defines a specific procedure for
12、the deter-mination of carboxyl end groups(CEG)of PET by a titrimetricmethod.4.2 PET yarns are dissolved in o-cresol at 80 C.Thesolution is diluted with dichloro methane,and titrated againstKOH dissolved in methanol,by either a potentiometric orcolorimetric method.The amount of potassium hydroxidereq
13、uired to complete the titration with the PET solution ismeasured and used to calculate to the concentration of CEGs.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.02 on Endur-ance Properties.Current edition appro
14、ved Dec.1,2020.Published December 2020.Originallyapproved in 2007.Last previous edition approved in 2015 as D7409 15.DOI:10.1520/D7409-15R20.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume i
15、nformation,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization
16、 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.5.Significance and Use5.1 This test method can be used for manufacturing qualitycontrol or manufacturing quality assurance purposes to deter-mine the CEG concentration of PET yarns used in eithergeogrids or geotextiles.5.2 The CEG content of the PET yarns may have aninfluence on the properties of the g
