Properties of insulating materials

An insulator must provide resistance to the electric current that’s why it is an insulator. Similarly, there are numerous properties in a good insulating material required.

Some other properties of insulating materials are discussed in this article.

What are insulating materials?

An insulating material is a substance that prevents the leakage of electric current. Not only for protection against the electric current but the material is also used for support, mechanical protection, and thermal isolation.

The valence band of the insulating materials is full. The energy gap between the conduction band and valence band is high. Therefore, the electrons present in the valence band are not able to move to the conduction band.

Read More: Energy band in insulators

Properties of insulating materials

properties of insulating materials

Below is the list of properties of insulating materials which are required in an insulating material.

  • Electrical properties
  • Mechanical properties
  • Thermal properties
  • Chemical properties

Now you have the complete list of properties of insulating materials, so we are going to further elaborate on these properties.

So, fellas let’s get started.

Electrical properties

Resistance: For an insulating material resistance is the crucial factor.

Imagine, how the material is an insulating material if it doesn’t provide resistance.

So, the insulating materials must provide resistance to resist the flow of electric current.

Therefore, a good insulating material has a large resistance.

Dielectric strength: It indicates the maximum electric field a material can withstand without experiencing failure of its insulating properties.

Low dielectric strength materials can easily break down under the influence of high electrical potential, allowing the leakage of charge. So, the dielectric strength of the material should be high.

The dielectric strength of a material is adversely affected by temperature, heat for a long period, weather, etc.

Power factor: The power factor measures how effectively the electric current is consumed or the loss of power in insulation. The value of the power factor should be low.

Mechanical properties

Strength: A key aspect of the solid insulator is strength.

Strength to bear heavy impact, strength to bear bends, etc.

Therefore the solid insulators must have tensile strength, bear strength, impact strength, bend strength.

Density: Electrical insulation is used based on volume and net weight.

Viscosity: It has significance in liquid dielectrics/insulators. Liquid dielectrics are commonly applied in transformers, motors, etc.

Uniform viscosity provides uniform electrical and thermal properties to liquid dielectrics. Therefore, uniformity in viscosity is important.

Moisture absorption: Moisture refers to liquid present in tiny traces. The moisture affects the electrical resistance, dielectric strength of the material.

So the material must not absorb moisture.

Uniformity: The insulating material must be uniform because it helps in providing uniform electric stress under high voltage differences.

It also keeps the electrical losses as low as possible.

Thermal properties

Thermal expansion: The material tends to change in shape, volume with the temperature change. In the case of insulating materials, it should be small.  

Ignitability: Insulating materials should be non-ignitable. Insulators used as electrical wires coating are exposed to very high voltages. A slight arc can cause an extremely dangerous situation if the insulator is ignitable.

Therefore, the insulating material must be non-ignitable, or it should be self-extinguishable.

Thermal conductivity: Thermal conductivity refers to the ability of a material to transfer heat. It is also known as the k-value.

Chemical properties

Resistance to the chemical in soils: Soil itself has numerous elements present in it eg. moisture, nutrients, etc. The soil can affect the underground cables used for many purposes.

Therefore, the insulating material should provide resistance from the soil. And the suitable material for these conditions can be decided by a long experience.

Resistance to other chemical effects: Insulating materials are used in various forms (solid, liquid, gaseous) and applied under many different conditions.

The insulating material must not react with the other chemicals present in different places. Therefore, the insulating materials should be resistant to the other chemicals (acids, alkalis, etc.).

Quick summary

  • The insulating material is the substance that provides resistance to the current.
  • The insulating material has a full valence band and an empty conduction band.
  • The properties of insulating material are required for the proper function of the insulating material.  

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