ASTM_D_4243_-_99_2009.pdf

Designation:D424399(Reapproved 2009)Standard Test Method forMeasurement of Average Viscometric Degree ofPolymerization of New and Aged Electrical Papers andBoards1This standard is issued under the fixed designation D4243;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 describes a standard procedure fordetermining the average viscometric degree of polymerization(abbreviatedDPv)of new or aged electrical papers.Thedetermination is made by measuring the intrinsic viscosity of asolution of the paper in an appropriate solvent.1.2 The degree of polymerization(or the degree of conden-sation)of a particular cellulose molecule is the number ofanhydro-glucose monomers,C6H10O5,in the cellulose mol-ecule.Within a sample of paper,not all the cellulose moleculeshave the same degree of polymerization so that the mean valuemeasured by viscometric methods is not necessarily the sameas that which may be obtained by other methods.1.3 This standard may involve hazardous materials,operations,and equipment.This standard does not purport toaddress all of the safety concerns,if any,associated with itsuse.It is the responsibility of the user of this standard toestablish appropriate safety and health practices and todetermine the applicability of regulatory limitations prior touse.See Section 92.Referenced Documents2.1 ASTM Standards:2D445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids(and Calculation of Dynamic Viscos-ity)D1711 Terminology Relating to Electrical Insulation2.2 Other Document:IEC 60450 Measurement of theAverage Viscometric Degreeof Polymerization of New and Aged Electrical Papers33.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D1711.4.Summary of Test Method4.1 This test method measures the specific viscosity of asolution of the paper in cupriethylenediamine.From thismeasurement the intrinsic viscosity of the solution is deduced,and from this the degree of polymerization is easily calculated.4.2 This test method follows very closely the proceduresspecified in IEC 60450.5.Significance and Use5.1 This test method may be applied to all papers made fromunmodified cellulose,as used in transformer,cable,or capaci-tor manufacture.It applies to new or aged papers.Forinformation,Appendix X1 shows an example of statisticaldistribution ofDPvvalues for new papers intended for theinsulation of transformers,together with information relative tocable and capacitor papers.Nevertheless,where evaluating thedecomposition stage of aged papers,take care to use,as areference,theDPvvalue of the new paper of the very sameorigin;DPvof new papers being a function,among otherfactors,of their specific gravity and of their manufacturingprocess.5.2 This test method can also be used for the determinationof the intrinsic viscosity of solutions of chemically modifiedpapers,provided that these dissolve completely in the selectionsolvent.This test method should be used with caution when itis applied to papers with mineral fillers.6.Interferences6.1 Lignins,that are present in measurable amounts in mostpapers and boards,may have an effect on the test results,1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.19 on Dielectric Sheet and Roll Products.Current edition approved Oct.1,2009.Published February 2010.Originallyapproved in 1983.Last previous edition approved in 2004 as D4243 99(2004)1.DOI:10.1520/D4243-99R09.2For 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.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 depending upon concentration and composition.For thisreason,it is important in aging studies to use as a referencesamples of the unaged paper as mentioned in 5.1.6.2 Under some conditions of heat and atmosphere,crosslinking of cellulose molecules may occur,resulting in erratictest values.This effect has been observed for capacitor tissue invacuum at temperatures as low as 110C and for other papersaged in air at higher temperatures.7.Apparatus7.1 Apparatus for Solution:7.1.1 Round-Bottomed 50-mL Flask,preferably with a shortnarrow neck,or a narrow-necked 50-mL Erlenmeyer flask.7.1.2 Rubber Stopper,fitting the neck of the flask,throughwhich passes a capillary tube fitted with a small-bore cockglass cock;or a ground stopper,fitted with a s