Insulators are considered those materials that offer resistance to the conduction of energy (thermal or electrical) , unlike conductive materials , which are those that conduct energy easily.
Insulating materials are usually classified into two large groups:
- Electrical insulators : are those materials that have a very low conduction capacity of electrical energy, because they generate a potential barrier that hinders the existence of free electrons capable of conducting electric currents. Electrical insulators are widely used when you want to avoid discharges in an electrical system, when you want to prevent people using electrical appliances from coming into contact with the current and to avoid short circuits.
- Thermal insulators : are those materials that, subjected to a source of heat, offer significant resistance before an increase in its temperature occurs. This does not mean that the thermal insulators do not conduct the caloric energy, since all the substances conduct the heat at least in small proportions, but they do it in a small enough extent to make them useful in case of wanting to isolate a certain source of energy caloric Thermal insulators are widely used in the metallurgical industry, in the aeronautical industry, in the energy industry and in construction.
Examples of thermal insulators
- Expanded cork
- Expanded polystyrene
- Glass foam
- Glass wool
- Wood chips
- Mineral wool or rock wool
- Phenolic resin foam
- Expanded perlite plates
- Elastomeric foam
- Extruded polystyrene
- Alveolar polyethylene film
- Polyurethane foam
- Cellulose foam
- Slabs of wood wool
- Cereal pellets
- Polyethylene foam
What makes a material insulating or conductor ?
The high or low conductivity of a material is determined by how strongly the electrons (which are subatomic particles with negative electrical charge) are firmly attached to the molecular structure, which leads electrons to require low amounts of energy in conducting materials. mobilize through the material , while in the insulators these amounts of energy must be much greater.
- Insulating materials : There are certain materials that are good insulators in general, such as glass and plastic , while others are only under certain specific conditions of temperature, pressure, or under a certain state of aggregation (such as the water, air or quartz).
- Semiconductor materials : There are even certain materials that have the property of being good insulators when they are in a pure crystalline state, as well as good conductors when the crystal atoms are combined with other materials, which is why they are called semiconductors (such as silicon and germanium).
- Superconducting materials : Superconductors are those materials that, when cooled, cease to exert resistance to the transmission of electric current, which implies that they have the capacity to acquire electric current even without resistance.