Electrical Paper - DP - IEC 60450

Electrical Paper - Degree of Polymerisation - IEC 60450

The PSL Rheotek RPV-3 Viscometer determines the average viscometric degree of polymerization (DP) of new and aged cellulosic electrically insulating papers in dilute solution using glass capillary viscometers in accordance with IEC 60450. The test method requires a concentration (C) of each sample in the range 0.5 < IV x C < 1.5. For a new insulating paper (DP range 1000 to 2000) this concentration will be in the range 0.05 to 0.15%. For a heavily aged electrical paper with an expected DP < 350, the approximate concentration will be in the range 0.25 to 0.8%.

Step by step

The cellulose is dissolved in Cupriethylenediamine (Cuen) and water, an alkaline solution. This solution will be sensitive to oxidation and it is essential that the viscometer is purged 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. The method requires that two repeat flow times are obtained within 1% precision. A repeat of the method is required with a fresh specimen of sample. The two results should agree to within 1% of each other The RPV-2 software automatically calculates the Intrinsic Viscosity from Martin's Formula. Using the pre-programmed Mark Houwink constants, the Average Degree of Polymerization (DP) is also calculated and reported.

Instrument set-up

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-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 for most papers a shaking time of 16 hours will be required for complete dissolution.