What is insulation made out of?

Question

Specifically, what materials are used to insulate? And what properties do they have that makes them good insulators?

Answer 1

Thermal insulators are poor conductors of heat.
Electrical insulators are poor conductors of electricity.

Thermal insulators are made of plastic foam (polyethelyne, polystyrene, etc,), spun fiberglass, or natural materials that can trap lots of air. Most thermal insulators are materials that have lots of little air pockets. Heat is slow to move through all of the air pockets and the plastic fibers that wrap around all the little air pockets.

Electrical insulation is made out of rubber or plastic material, or some natural materials like spun cotton. Electrical insulators do not have any valance band electrons, and it takes a LOT of energy to move the electrons (tightly bound) to a conduction band, compared with a conductor.

Some thermal insulators can make good electrical insulators, and vice-versa.

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Answer 2

Everything conducts heat, but some materials are very good conductors and some are poor conductors. Insulation is made of materials that are poor conductors. The best insulation is air, because it is a gas and gases are much poorer conductors than solids and liquids. Also they are lighter, and light weight is always desirable for insulation.

The problem with air is it moves around too much. It has to be trapped and held in small pockets to be a good insulator. Therefore, the best insulators are made of something light that traps air. Glass and plastics are poor conductors that can be used to trap air.

The insulation in your house is probably fiberglass or styrofoam or some other kind of foam. Fiberglass is made of very fine hairlike glass filaments, loosely packed together. Foams are made of plastic materials that have microscopic bubbles of air permanently trapped in them.

Insulation for your clothes is made of fine synthetic fibers that also trap and hold a lot of air. Natural insulation comes in the form of fur on mammals and down on birds. Fur is composed of very fine hairs that grow very closely packed on the skin. Down is made of very fine hairlike fibers of keratin, which also grow from the skin like feathers. Feathers and fingernails are made of the same thing in a different form.

Answer 3

I suppose you talk about electrical insulation, not heat, or noise, or....
Any material which does not have free electrons can be used as insulator.
In practice, for price and manufacturability reasons, certain materials are preferred.
For example, in the "old days" porcelain and rubber was widely used, but then phased out.
One of the "best" materials are Silicon Dioxide and Teflon, but for less demanding applications polymers that resemble rubber in some way, and different plastics can be used.
Finally, good insulation material should not be porous and absorb moisture. So wood, for example, is no good....

Answer 4

Insulation is made out of material that have a low conductance rate for heat (Low C). Most often the inverse of C is used and called resistance. This is where R-values for insulation come from.

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Answer 5

Lots of materials are used for insulators. Plastics, teflon, ceramic, air, it all depends on the voltages and the application. The only real 'property' that an insulator requires (to be an insulator) is that it be a very poor conductor of electrical current.

Doug

Answer 6

I was in a wet formed cavern in Missouri carved out of limestone. That limestone resonated at a constant humidity and low 60 degree temperature.

I property maybe mass.