IEC 60450-ed.2.0

Detail information

Designation: IEC 60450-ed.2.0

Publication date: 19/04/2004

Pages: 45

Country: International technical standard

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Anotation

Describes a standardized method for the determination of the average viscometric degree of polymerization (DPv) of new and aged cellulosic electrically insulating materials. It may be applied to all cellulosic insulating materials such as those used in transformer, cable or capacitor manufacturing. The methods described can also be used for the determination of the intrinsic viscosity of solutions of chemically modified kraft papers, provided that these dissolve completely in the selected solvent. Caution should be taken if the method is applied to loaded kraft papers. Note: Within a sample of material, all the cellulose molecules do not have the same degree of polymerization so that the mean value measured by viscometric methods is not necessarily the same as that which may be obtained by, for instance, osmotic or ultra centrifuging methods. Experience has indicated the need for improved description of the experimental method. It describes a revised procedure that overcomes the limitations of the first edition. Decrit une methode normalisee pour determiner le degre de polymerisation moyen viscosimetrique (DPv) des materiaux isolants cellulosiques neufs et vieillis, a usage electrique. Elle peut sappliquer a tous les materiaux isolants cellulosiques comme ceux utilises dans la fabrication des transformateurs, des cables et des condensateurs. Les methodes decrites peuvent egalement etre utilisees pour determiner la viscosite intrinseque des solutions de papiers kraft modifies chimiquement, pourvu que ceux-ci se dissolvent totalement dans le solvant choisi. Il convient de prendre des precautions si la methode sapplique a des papiers kraft charges. Note: Dans un echantillon de materiau, toutes les molecules de cellulose nont pas le meme degre de polymerisation de sorte que la valeur moyenne mesuree par les methodes viscosimetriques nest pas necessairement la meme que celle obtenue, par exemple, par les methodes par osmose ou par ultra-centrifugation. Lexperience a mis en evidence le besoin dameliorer la description de la methode experimentale. La procedure ainsi revue permet de surmonter les limitations de la premiere edition.