ASTM_D_6980_-_12.pdf

Designation:D698012Standard Test Method forDetermination of Moisture in Plastics by Loss in Weight1This standard is issued under the fixed designation D6980;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()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the quantitative determinationof moisture by means of loss in weight technology down to 50mg/kg as it applies to most plastics.1.2 The values stated in SI units are to be regarded as thestandard.1.3 Specimens tested by this method will be hot,use cautionwhen handling them after testing has been completed.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.NOTE1There is no known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD6869 Test Method for Coulometric and Volumetric Deter-mination of Moisture in Plastics Using the Karl FischerReaction(the Reaction of Iodine with Water)E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 DefinitionsThe definitions used in this test method arein accordance with Terminologies D883 and D1600.3.2 Symbols:3.2.1 liftthe result of convection currents created duringthe heating of the specimen raising the sample pan off of itssupport falsely indicating a moisture loss.3.2.1.1 DiscussionThe effects of lift are compensated forin different ways by different manufacturers.3.2.2 temperinga process that re-defines the molecularstructure of a metal to enhance its performance.4.Summary of Test Method4.1 The specimen is spread onto a sample pan that issupported on a balance in a heating chamber that has beenpreheated and equilibrated to the specified idle temperature.Itis then heated to vaporize the moisture.The analysis iscompleted when the indicated weight loss falls below a ratespecified in the test conditions.The total loss of weight isintegrated and displayed as the percent of moisture.Both theanalyzers balance and heater are calibrated to NIST standardsto achieve precise and accurate results.4.2 Through adjustment of the analyzers parametersettings,a set of conditions is developed to measure moisture.5.Significance and Use5.1 This test method is intended for use as a control,acceptance,and assessment test.5.2 Moisture will affect the processability of some materi-als.For these materials,defects will occur if they are processedwith a moisture content outside of the recommended range.5.3 The physical properties of some plastics are greatlyaffected by the moisture content.6.Interferences6.1 When testing plastic materials for moisture by a loss inweight technique,the possibility exists for volatiles other thanmoisture to be evolved and cause a biased high result if thematerial has not been dried to remove excess moisture and lowboiling volatiles.It is important to have a working knowledgeof the material that is being tested and to remain below anymelting or decomposition temperatures that would unnecessar-ily cause the emission of volatiles which can be harmful.7.Apparatus7.1 Moisture Analyzer,containing:7.1.1 The capability of the oven shall be selected basedupon the specific material being tested.Suggested test tem-peratures for specific plastics are shown in Tables A1.1 andA2.1.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.70 on Analytical Methods.Current edition approved Feb.1,2012.Published March 2012.Originallyapproved in 2004.Last previous edition approved in 2009 as D6980-09.DOI:10.1520/D6980-12.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 NOTE2It will be necessary to contact the analyzer manufacturer forsuggested test temperatures for materials not listed in Tables A1.1 andA2.1.7.1.2 A balance capable of measuring to 0.0001 g.7.1.3 An electronic or mechanical means of compensatingfor lift caused by convection currents created during testing.7.1.4 A processor that is capable of converting the loss ofweight to digital data.7.1.5 Digital display for presenting the digital data aspercent moisture.7.1.6 Sample Pans,made from“0”temper,Aluminum 3003or other nonreactive material.8.Test Specimen and Sample8.1 Due to the small s