Polymer Dielectric Constant Table

The ratio of the charge that can be stored when an insulating material is placed between two metallic plates compared to the charge that can be stored when the insulating material is replaced by vacuum or air is known as the dielectric constant (Dk) of a plastic, dielectric, or insulating material. It is also known as electric permittivity or just permittivity.

Polymer Dielectric Constant Calculation

To measure the polymer dielectric constant, the sample must be flat and larger than the 50mm (2 inch) circular electrodes used for the measurement.
As the dielectric constant is calculated relative to the permittivity of free space (ε0), it is also occasionally referred to as relative permittivity. Its value is calculated as follows:

Where:

C = capacitance with the material as the dielectric

C₀ = capacitance with vacuum as the dielectric

ε₀ = free space permittivity (8.85 x 10-12 F/m, i.e. Farad per metre)

A = it is the area of cross section of the plate or sample

T = sample thickness

The three most often used standard tests to determine a plastic’s dielectric constant are ASTM D2520, ASTM D150, or IEC 60250.

Factors Influencing Dielectric Constant

·        Dielectric constant falls sharply with increasing frequency.

·        Temperature and Moisture

·        Voltage morphology and structure

·        Additional elements present in the plastic

·        Weathering and Decreasing Quality

Polymer Dielectric Constant Table