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TAPPI T 230 Pulp viscosity






Viscosity of pulp (capillary viscometer method)


TAPPI T 230 Pulp Viscosity describes a procedure for determining the viscosity of 0.5% cellulose solutions, using 0.5M cupriethylenediamine (CED) as a solvent and a capillary viscometer. Measurements may be made on bleached cotton and wood pulps. Conventional kraft pulps with up to 4% lignin, as defined by TAPPI T 222 “Acid-Insoluble Lignin in Wood and Pulp” can also be analyzed. The applicability of this procedure to extended delignification pulps has not been determined.


The solution viscosity of a pulp gives an indication of the average degree of polymerization of the cellulose. Such a test therefore gives a relative indication of the degradation (decrease in cellulose molecular weight) resulting from the pulping and/or bleaching process. Caution should be exercised in drawing conclusions about pulp strength properties strictly from viscosity results unless previous investigation has identified the relationship.


To perform adequate testing the equivalent of seven (7) oven dried grams is desired. This ensures that handsheets may be made from the samples, moisture can be tested and duplicate testing can be run. If sample availability is limited, testing can be performedusing less sample. Sample may be received as handsheets, slush, or lap sample. The test is performed on 0.25 oven dried grams.


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