Pulp - IV - ASTM D1795

Pulp & Cellulose, Intrinsic Viscosity - ASTM D1795

The PSL Rheotek RPV-3 Pulp Viscometer determines the Intrinsic Viscosity (IV) of purified celluloses in dilute solution using glass capillary viscometers in accordance with ASTM D1795. The test method requires a concentration (C) of each sample according to the rule IV x C = 3.09+/-0.5. For a regular dissolving pulp (IV range 3 to 10 dL/g) this concentration will be in the range 0.3 (high viscosity) to 1% (low viscosity). A native celluluse with an IV range between 15 to 30 dL/g, the approximate concentration will be in the range 0.1 to 0.2%. For a regenerated cellulose such as rayons, the concentration will be 1% with a corresponding expected IV in the range 2 to 3 dL/g. The cellulose is dissolved in Cupriethylenediamine (CED), an alkaline solution. This solution will be senstive to oxidation.

Step by step

Solvent and solution flow times are measured at 25 deg. C typically using a size 1B size of suspended-level Ubbelohde type viscometer for both measurements (allowing for a kinetic energy correction). The method requires that two repeat flow times are obtained within 0.3% precision. The RPV-2 software automatically calculates the Intrinsic Viscosity from each single determination using the table set out in ASTM D1795. In addition, the Degree of Polymerization (DP) can also be reported. The dual position RPV-3 (2) Pulp Viscometer (with nitrogen purge) is an ideal configuration for this method, as well as the RPV-3 (4) Pulp Viscometer. The iSP-2 Pulp Sample Preparation system can be used in conjunction with the RPV-2 to prepare samples on a precise weight to weight basis, taking into account the moisture content of the sample. Dissolution is carried out using a wrist action shaker (WAS) or reaction block with magnetic stirring.

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