ASTM_D_778_-_97_2002.pdf

Designation:D 778 97(Reapproved 2002)An American National StandardStandard Test Methods forHydrogen Ion Concentration(pH)of Paper Extracts(Hot-Extraction and Cold-Extraction Procedures)1This standard is issued under the fixed designation D 778;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 These test methods cover two procedures for determi-nation of the hydrogen ion concentration,expressed in terms ofpH,of an aqueous extract of paper.1.2 These test methods may be applied to writing,printing,and sized industrial papers.1.3 These test methods are not intended to be used fordetermination of pH of insulating papers,for that see TestMethods D 202.1.4 The test methods appear as follows:SectionTest Method ApH of Paper(Unfiltered Extract)AfterExtraction for 1 h in Cold(25 6 5C)Water11.1Test Method BpH of Paper(Unfiltered Extract)AfterExtraction for 1 h in Boiling Water11.21.5 Specifications may be based on Test Method A or TestMethod B,or both.1.6 Where a specification or specific instructions or agree-ment to use only one of these test methods is absent,determinepH using both procedures,and interpret results based onSection 12.1.7 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 202 Test Methods for Sampling and Testing UntreatedPaper Used for Electrical Insulation2D 585 Practice for Sampling and Accepting a Single Lot ofPaper,Paperboard,Fiberboard and Related Product3D 1193 Specification for Reagent Water4D 1293 Test Methods for pH of Water4D 1968 Terminology Relating to Paper and Paper Products3E 70 Test Method for pH of Aqueous Solutions With theGlass Electrode5E 122 Practice for Choice of Sample Size to Estimate aMeasure of Quality for a Lot or Process63.Terminology3.1 Definition:Definitions shall be in accordance withTerminology D 1968 and the Dictionary of Paper.74.Summary of Test Methods4.1 Test Method A consists of the extraction of a 1-g testspecimen in 70 mL of cold distilled water(25 6 5C)for 1 h,and determination of pH without filtration using a commercialpH meter.4.2 Test Method B consists of the extraction of a 1-g testspecimen in 70 mL of boiling distilled water for 1 h,followedby cooling of the extract and determination of the pH withoutfiltration using a commercial pH meter.5.Significance and Use5.1 The acidity or alkalinity of a paper sample extract isimportant because of the effect of paper acidity or paperalkalinity on the permanence of the paper.Although acidity oralkalinity may be determined by titration the pH is often moreindicative of the stability of paper than is the total acidity oralkalinity.6.Apparatus6.1 pH MeterUse a pH meter of Type II or Type III asspecified in Test Methods D 1293.In general terms this is a pHmeter accurate to 0.01 pH units with temperature compensationsuitable for making pH measurements over the 0 to 14-pHrange.6.2 Reflux condensers,preferably water cooled,West orAllihn Type,with 300-mm jackets,standard taper inner jointsand drip tips;or air condensers,10-mm diameter and 1000 mmlong with ST inner joints and drip tips,ST joints to fit the flasks(required on hot-extraction procedure,only).1These test methods are under the jurisdiction of ASTM Committee D06 onPaper and Paper Products and are the direct responsibility of Subcommittee D06.92on Test Methods.Current edition approved Dec.10,1997.Published November 1998.Originallyapproved in 1944.Last previous edition approved in 1993 as D 778 93.2Annual Book of ASTM Standards,Vol 10.01.3Annual Book of ASTM Standards,Vol 15.09.4Annual Book of ASTM Standards,Vol 11.01.5Annual Book of ASTM Standards,Vol 15.05.6Annual Book of ASTM Standards,Vol 14.02.7Available from the Technical Association of the Pulp and Paper Industry,P.O.Box 105113,Atlanta,GA 30348.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.7.Reagents7.1 Distilled WaterThe distilled water used in these testmethods must comply with Type II or Type III reagent water asspecified in Specification D 1193.7.2 Standard Buffer Solutions:7.2.1 If buffer solutions are prepared in the laboratory,theirpreparation and corporation must comply with applicablesections of Test Method E 70 or Test Methods D 1293.Someknowledge of the expected pH may be required to indicatewhich buffers(pH values)will be required for use.7.2.2 Commercially available pH buffers may be used ifdesired.Common pH values are 4.0,7.0,and 10.0.Purchasethe ones appropriate for samples being tested.8.Sampling8.1 Acceptance Sampli