Degree of Polymerisation

The degree of polymerisation is a measure of the insulating performance of paper and board materials used in the construction of electrical transformers.

The degree of polymerization is measured using viscometer techniques after a sample of material has been dissolved in a solvent. The average number of glucose units in the cellulose polymer that constitutes the paper or board material is determined. The length of the polymer has a direct relationship with the insulating properties of the material.

As the paper or board ages, the cellulose polymer chains within the material degrade into smaller units. Faults such as overheating and arcing will also cause degradation of the polymer chains.

Pira testing is performed to the ASTM standard D 4243.

Expert Profile

  • Doug joined Pira in 1989 and has 20 years experience in the physical testing of packaging and packaging materials. He heads a team specialising in packaging and print related technical investigations. In 2004 Doug gained his postgraduate degree with distinction in Packaging Technology from Brunel University.

    Doug Leatherdale
    Doug Leatherdale

    Head of Physical Testing

    Pira International

    +44 1372 80 2108

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