1、Designation:D529611Standard Test Method forMolecular Weight Averages and Molecular WeightDistribution of Polystyrene by High Performance Size-Exclusion Chromatography1This standard is issued under the fixed designation D5296;the number immediately following the designation indicates the year oforigi
2、nal 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.Scope*1.1 This test method covers the determination of molecularweight(MW)averag
3、es and the distribution of molecularweights for linear,soluble polystyrene by high-performancesize-exclusion chromatography(HPSEC).This test method isnot absolute and requires the use of commercially availablenarrow molecular weight distribution(MWD)polystyrenestandards for calibration.This test met
4、hod is applicable forsamples containing molecular weight components that haveelution volumes falling within the elution volume rangedefined by polystyrene standards(that is,molecular weightsgenerally from 2000 to 2 000 000 gmol1).1.2 The HPSEC is differentiated from traditional size-exclusion chroma
5、tography SEC(also referred to as gel perme-ation chromatography(GPC)in that the number of theoreticalplates per metre with an HPSEC system is at least ten timesgreater than that for traditional SEC(see Terminology D883and Practice D3016).2The HPSEC systems employ low-volume liquid chromatography com
6、ponents and columnspacked with relatively small(generally 3 to 20 m)micropo-rous particles.High-performance liquid chromatography in-strumentation and automated data handling systems for dataacquisition and processing are required.1.3 The values stated in SI units are to be regarded as thestandard.1
7、.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 regulatory limitations prior to use.Specific precau-tio
8、nary statements are given in Section 9.NOTE1There is no known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:3D883 Terminology Relating to PlasticsD2857 Practice for Dilute Solution Viscosity of PolymersD3016 Practice for Use of Liquid Exclusion Chromatogra-phy Terms and Re
9、lationshipsE685 Practice for Testing Fixed-Wavelength PhotometricDetectors Used in Liquid ChromatographyE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 DefinitionsFor definitions of technical terms pertain-ing to plastics used in this
10、test method see Terminology D883.4.Summary of Test Method4.1 In this test method a dilute solution of a polystyrenesample is injected into a liquid mobile phase containing thesame solvent used to prepare the polymer solution.The mobilephase transports the polymer into and through a chromato-graphic
11、column(or set of columns connected in series)packedwith a solid or semirigid,porous substrate which separates thepolymer molecules according to their size in solution.Startingfrom injection,a detector continuously monitors the eluate as afunction of elution volume(or time).Upon emerging from thecolu
12、mn(s),the size-separated molecules are detected andrecorded according to their concentration.Through calibration,the elution volumes(or times)are converted to molecularweights,and various molecular weight parameters for thesample are calculated from the molecular weight/concentrationdata.5.Significa
13、nce and Use5.1 General UtilityThe molecular weight(MW)and mo-lecular weight distribution(MWD)are fundamental character-istics of a polymer sample.They are used for a wide variety of1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcom
14、mittee D20.70 on Analytical Methods.Current edition approved Sept.1,2011.Published September 2011.Originallyapproved in 1992.Last previous edition approved in 2005 as D5296-05.DOI:10.1520/D5296-11.2See also AMD Bibliography and Bibliography Supplements AMD 40-S1,40-S2,and 40-S3 on Size Exclusion Chr
15、omatography,available fromASTM Headquarters.3For 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.*A Summary of Changes
16、section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 correlations for fundamental studies,processing,or productapplications.For example,the observed MWD is compared toone predicted from assumed kinetics or mechanisms for apolymerization reaction.Differences between the values willallow alteration of theory or experimental design.Similarly,thestrength,melt flow,and other properties of a polymer sam
