Thermoset vs. Thermoplastic

Thermoset and thermoplastic materials are found in the insulation and jacketing of many cables on the market today. Though their names sound similar, they are two distinct materials with very different mechanical properties.

Thermoplastic materials consist of chains of molecules which separate when heat is applied. This molecular construction gives thermoplastics the ability to melt and remold time and time again.

On the other hand, thermoset materials consist of polymer structures which are cured or vulcanized to become natural or synthetic rubber materials. Irradiation, heat, or chemical reactions can be used to cure the material. During the curing process, polymer chains are cross-linked with other molecules which is why thermoset materials are also known as cross-linked materials. On product spec sheets, this is represented with the letters XL.

Example: XLPE
Cross-Linked Polyethylene

Once cured, thermoset materials are irreversibly molded. Unlike thermoplastics, they will burn when excessive heat is applied because their melting point is simply too high to reach. The materials degrade and decompose before they can reach temperatures high enough to melt.

As a result, thermosets are great solutions for high temperature applications or for circuits at risk for overload. High temperature ratings make them more likely to function if an application overheats suddenly.

Thermoplastics are commonly utilized in automated equipment and high volume applications. Thermoplastics are easier to work with than thermoset materials. They can also be easily stripped if an application requires.

Although thermoset and thermoplastic materials are very different, each has their place in wire and cable construction. Choice of material simply depends on the requirements of a particular application.

Learn about more about the different materials used as cable insulation and jacketing.


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