ASTM_D_5318_-_97.pdf

Designation:D 5318 97Standard Test Method forHydrolyzable Chloride in Peroxy Esters and PeroxyDicarbonates1This standard is issued under the fixed designation D 5318;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(e)indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers determination of the hydrolyz-able chloride content of peroxy esters and peroxy dicarbonates.NOTE1There are no ISO standards covering the primary subject ofthis test method.1.2 The values stated in SI units are to be regarded as thestandard.1.3 The text of this standard references notes and footnoteswhich provide explanatory material.These notes and footnotes(excluding those in tables and figures)shall not be consideredas requirements of this standard.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 and health practices and determine the applica-bility of regulatory limitations prior to use.Specific hazardsstatements are given in Section 8.2.Referenced Documents2.1 ASTM Standards:D 883 Terminology Relating to Plastics2D 1193 Specification for Reagent Water3D 1600 Terminology for Abbreviated Terms Relating toPlastics2E 200 Practice for Preparation,Standardization,and Stor-age of Standard and Reagent Solutions for ChemicalAnalysis43.Terminology3.1 GeneralUnless otherwise indicated,definitions are inaccordance with Terminology D 883 and abbreviations are inaccordance with Terminology D 1600.4.Summary of Test Method4.1 The hydrolyzable chloride content of the peroxy ester orperoxy dicarbonate is determined volumetrically using silvernitrate titrant after the alkaline hydrolysis of the material.Theend point of the titration is detected potentiometrically.5.Significance and Use5.1 Peroxy esters and peroxy dicarbonates are used widelyas initiators and chemical intermediates in the production andmodification of polymers,including PVC,polyethylene,andpolypropylene.The level of hydrolyzable chloride in theperoxide species may affect its performance in some applica-tions.This test method provides a procedure for determiningthe hydrolyzable chloride content of peroxy esters and peroxydicarbonates.5.2 As measured by this test method,hydrolyzable chlorideis defined as the sum of the inorganic chloride content plus thechloride content generated upon alkaline hydrolysis of theperoxy ester or peroxy dicarbonate.6.Apparatus6.1 Automatic Potentiometric Titrimeter,consisting of apotentiometer with a 62-mV sensitivity,a buret graduated in0.001-mL divisions,and a mechanical stirrer.6.1.1 A system consisting of a Metrohm AG Model 682Titroprocessor with a Model 664 Control Unit and a Model 665Dosimat5has been used successfully.6.2 Combined Silver ElectrodeBrinkman InstrumentsCatalog No.020-92-460-8(Metrohm AG 6.0404.100)5orequivalent.7.Reagents7.1 Purity of ReagentsReagent-grade chemicals shall beused in all tests.It is intended that all reagents shall conform tothe specifications of the Committee on Analytical Reagents ofthe American Chemical Society,where such specifications are1This test method is under the jurisdiction ofASTM Committee D-20 on Plasticsand is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materi-als.Current edition approved July 10,1997.Published April 1998.Originallypublished as D 5318 92.Last previous edition D 5318 92.2Annual Book of ASTM Standards,Vols 08.01 and 08.04.3Annual Book of ASTM Standards,Vol 11.01.4Annual Book of ASTM Standards,Vol 15.05.5Available from Brinkman Instruments,Inc.,One Cantiague Road,Westbury,NY 11590-0207.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.available.6Other grades may be used,provided it is firstascertained that the reagent is of sufficiently high purity topermit its use without lessening the accuracy of the determi-nation.7.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean Type II or III reagentwater conforming to Specification D 1193.7.3 Isopropyl Alcohol,pesticide residue grade.7.4 Nitric Acid(46 g/L)Dilute 3.0 mL of concentratednitric acid to 100 mL with water.7.5 Silver Nitrate(0.1 mol/L)Prepare and standardize inaccordance with the appropriate sections of Practice E 200.7.6 Silver Nitrate(0.005 mol/L)Dilute 50.00 mL of silvernitrate(0.1 mol/L)to 1 L in a volumetric flask.7.7 Sodium Hydroxide(1:50)Dissolve 2.0 g of sodiumhydroxide pellets in 100 mL of water.8.Hazards8.1 Organic peroxides are strong oxidizing agents andpresent potential fire and explosion hazards.Avoid contact withreducing agents and sources of heat,sparks,or open flames.Reactivity varies wi