Electrical Paper - DP - ASTM D4243

Electrical Paper - Degree of Polymerization - ASTM D4243

The PSL Rheotek RPV-3 Pulp Viscometer determines the average viscometric degree of polymerization (DPv) of new and aged electrical papers and boards in dilute solution using glass capillary viscometers in accordance with ASTM D4243. The test method requires three levels of concentration depending upon the DPv range of each sample. The cellulose is dissolved in Cupriethylene-diamine (CED), an alkaline solution. This solution will be sensitive to oxidation and it is essential that the viscometer is flushed thoroughly with nitrogen. Solvent and solution flow times are measured at 20 deg. C typically using a size 1 suspended-level Ubbelohde type viscometer for both measurements.

Step by step

The method requires that three successive flow times are obtained within a difference of less than 0.5s between the maximum and minimum time. If this precision is not obtained the test should be repeated with a fresh solution. All tests should be carried out in duplicate. DPv values should agree within 2.5% of their mean value. The RPV-3 software automatically calculates the Intrinsic Viscosity from the specific viscosity and concentration by Martin's Formula. Using the pre-programmed Mark Houwink constants, the Average Degree of Polymerization (DPv) is also calculated and reported.

Recommended configuration

The dual position RPV-3 (2) Pulp Viscometer (with nitrogen purge) is an ideal configuration for this method, as well as the RPV-2 (4) Pulp Viscometer. The iSP-2 Pulp Sample Preparation system can be used in conjunction with the RPV-3 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. Note depending upon the age of the paper a shaking time from 2 to 18 hours will be required for complete dissolution.