ASTM_D_3536_-_91_scan.pdf

-ASTM D3536 93 W 0759530 0503334 B m Tb Designation:D 3536-91 AMERICAN SOCIETY FOR TESTING AND MATERIALS 1916 RaceSt Philadelphia,Pa 19103 Reprlnted from the Annual Bookof ASTM Standards.Copyright ASTM If not listed in the current combined index,will appear i n the ne*ediion.Standard Test Method for Molecular Weight Averages and Molecular Weight Distribution by Liquid Exclusion Chromatography(GEL Permeation Chromatography-GPC)This standard is issued under the fixed designation D 3536;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(0 indicates an editorial change since the last revision or reapproval.1.Scope 1.1 This test method covers the determination of molec-ular weight(MW)averages and the distribution of molecular weights in linear soluble polystyrene by liquid exclusion chromatography(gel permeation chromatography-GPC).The test method uses commercially available polystyrene(PS)standards and equipment for this purpose and is applicable for samples containing molecular weight compo-nents from 5000 to 3 X lo6 g-mol-.This is discussed in more detail in 12.1.The test method is not absolute and requires calibration.1.2 The values stated in SI units,based on Practice E 380,are to be regarded as the standard.1.3 This standard does not purport to address all o f the safety problems,if any,associated with its use.It is the responsibility of the user o f this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents 2.1 ASTM Standards:D 30 16 Practice for Use of Liquid Exclusion Chromatog-E 380 Practice for Use of the International System of 2.2 Other Document:AMD 40 Bibliography on Liquid Exclusion Chromato-raphy Terms and Relationshipsz Units(SI)3 PPhY4 3.Summary of Test Method 3.1 In this technique a solution of a polymer sample is injected into a chromatographic column(series)packed with a solid,porous substrate which separates the diverse mole-cules according to their size in solution.The size-separated molecules are detected and recorded according to their concentration.Through calibration,sues are converted to molecular weights,and various molecular weight parameters for the sample are calculated from the molecular weight/concentration data.This test method is under the jurisdiction of ASTM Committee D-20 on Plastics and is the direct responsibility of Subcommittee D20.70 on Analytical Methods(Section D20.70.02).Current edition approved Nov.15,1991.Published January 1992.Orginally published as D 3536-76.Annital Book ofASTM Standards,Vol 08.02.Aiinilal Book o f ASTM Standards,Vol 1 4.0 2.Available from ASTM,1916 Race St.,Philadelphia,PA 19103.4.Significance and Use 4.1 General Utility-The molecular weight(MW)and molecular weight distribution(MWD)are fundamental char-acterisfia of a polymer sample.They may be used for a wide variety of correlations for fundamental studies or product applications.For example,the observed molecular weight distribution may be compared to a predicted one from assumed kinetics or mechanisms of reaction,or both.Differences between the values will allow alteration of theory or experimental design.Similarly,strength,melt flow,and other properties may be dependent on molecular weight and molecular weight distribution.4.2 Limitations-Because of the need for specific calibra-tion of the polymer type under study,and because of the specific nature of polymer/solvent/column-packing interac-tions,this test method is valid only for polystyrene.How-ever,many of the principles of the test method may be used to generate methods for other polymer systems.5.Units and Symbols 5.1 Terms and relationships for this test method are defined in Practice D 3016.5.2 Related to Function:SI Unit or Function Common Unit or Symbol Symbol Basic property definition Solvent flowrate Sample volume or capacity Column lengths Sample weight(mass)Pore size Chromatogram heights A Same as common unit.MW(molecular g-mol-weight in ciaitons)mL.min-1 m3.s-I A A A A A PL,mL cm mg Pm mm 5.3 Equivalencies Used in This Test Method:Si Unit or Symbol 1.667 x 10-9m3.s-L I I mL-min-Common Unit or Symbol 6.Apparatus 6.1 Introduction-Liquid exclusion chromatography(GPC)is a specific form of liquid chromatography.The principal distinguishing features of GPC are the column NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.D3536 I I I SAMPLE INJECTION SYSTEM Y-DETECTOR WASTE FIG.1 Schematic of 8 GPC System packing materials which are discussed below.6.2 Essential Components-The essential components of instrumentation are a solvent reservoir,a pump,sample injection system,packed columns,a solute detector,and a flowrate detector.The interreIationships of