ASTM_D_548_-_97_2002.pdf

Designation:D 548 97(Reapproved 2002)An American National StandardStandard Test Method forWater-Soluble Acidity or Alkalinity of Paper1This standard is issued under the fixed designation D 548;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.Scope1.1 This test method covers the determination of the water-soluble acidity or alkalinity of paper.21.2 It may be applied to writing,printing,and sized indus-trial paper but is not intended for testing electrical insulatingpapers nor those containing alkaline fillers or coatings such ascasein or calcium carbonate.1.3 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.2.Referenced Documents2.1 ASTM Standards:D 585 Practice for Sampling and Accepting a Single Lot ofPaper,Paperboard,Fiberboard,or Related Product3D 644 Test Method for Moisture Content of Paper andPaperboard by Oven Drying3D 1193 Specification for Reagent Water4D 1293 Test Methods for pH of Water4D 1968 Terminology Relating to Paper and Paper Products3E 70 Test Method of pH of Aqueous Solutions with theGlass Electrode52.2TAPPI Standard:T 1206 Precision statement for test methods63.Terminology3.1 DefinitionsDefinitions shall be in accordance withTerminology D 1968 and the Dictionary of Paper.64.Summary of Test Method4.1 This test method consists of a boiling-water extractionof the specimen followed by an alkalinity-acidity titration ofthe extract solution.4.2 This test method,based on the work of Kohler andHall,2measures the titratable acidity or alkalinity(end point at7.0 pH)of an aqueous extract of paper(filtered and extractedby boiling water for 1 h).It specifies one extraction and so doesnot measure the total acidity or alkalinity of paper,for whichexhaustive extraction is required.5.Significance and Use5.1 The pH determination measures the extent to which thepaper alters the hydrogen-hydroxyl ion equilibrium of purewater,and the acidity-alkalinity determination measures thequantity of extracted ionic material that contributes to thatequilibrium change.These tests are useful for routine accep-tance testing,research work,or the evaluation and classifica-tion of different papers.6.Apparatus6.1 pH meter,a commercial pH meter including a glasselectrode,reference electrode,and electronic circuitry that willmeasure electromotive force and indicate pH directly with aprecision of 0.01 pH unit(see Fig.1).A pH meter of Type II,III,or IV as described in Test Methods D 1293 is satisfactory,and shall be calibrated and used in accordance with Specifica-tion E 70.6.2 Balance,an analytical balance sensitive to 0.1 mg.6.3 Hot Plate,with temperature regulator.NOTE1A steam or oil bath that can be maintained at 100C may besubstituted,if available.6.4 Glassware,Acid-and Alkali-Resistant:1This test method is under the jurisdiction of ASTM Committee D06 on Paperand Paper Products and is the direct responsibility of Subcommittee D06.92 on TestMethods.Current edition approved Dec.10,1997.Published November 1998.Originallyapproved in 1939.Last previous edition approved in 1995 as D 548 91(1995)e1.2This test method is based on the method for acidity described by S.Kohler,andG.Hall,in“Acidity in Paper,”(The Paper Industry,Vol 7,No.7,Edward B.Fritz,pub.,October 1925,pp.1056-1063)with some modifications developed at theNational Bureau of Standards.In this revised method,one extraction is specifiedinstead of the three extractions originally specified,because Kohler subsequentlyfound that one extraction is sufficient for classification of paper.See“Investigationinto the Determination of Acidity and Copper Number in Paper,”Meddelande 56Statens Provingsanstalt,Stockholm,1932.In this article,it is stated that the acidnumber thus obtained is about three fourths of that obtained by three extractions.Studies of this test method and other acidity methods are reported by B.L.Wehmhoff,in Technical Association Papers,Technical Association of the Pulp andPaper Industry,May 1930 and May 1931.3Annual Book of ASTM Standards,Vol 15.09.4Annual Book of ASTM Standards,Vol 11.01.5Annual Book of ASTM Standards,Vol 15.05.6Available from the Technical Association of the Pulp and Paper Industry,Technology Park,P.O.Box 105113,Atlanta,GA 30348.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.6.4.1 Erlenmeyer Flask,500-mL with 24/40 standard taperjoint.6.4.2 Condenser,West or Allihn type,with 300-mm jacket;or an air condenser about 12 mm outside diameter and 750 mmlong;each with a 24/40 standard taper drip-tip joint.6.4.3 Burets,two