Thermoplastics Vs. Thermosets

While often confused with plastics, polymers actually consist of a wider range of substances, whether they are naturally occurring or artificially made. Polymers can be divided into one of two categories: thermoplastics or thermosets.

Recyclability

The primary difference between thermoplastics and thermosets is their reaction to heat. While both types of polymers are originally molded using heat, once a thermoset---sometimes referred to as a thermosetting polymer---cools, it cannot be reheated and reshaped. Instead, it will only char. Thermoplastics, on the other hand, can be reheated and reshaped any number of times.

Composition

The bonds between molecules in a thermoplastic do not chemically bond together when they cool. Because of their weak bonds, thermoplastics can be reheated and melted back down. The bonds between molecules in a thermoset do chemically set, and thus cannot be melted back down by reheating. This difference in bonding also makes thermosets harder and more brittle.

Formation

Polymers are used in almost limitless applications. From bottles, cookware and microprocessors to uses in the biomedical field, both thermoplastic and thermoset polymers are constantly used in our everyday lives. Because they cannot be reheated, thermosets are shaped into the final product immediately following their creation. Thermoplastics are often heated and cooled into molds and are later formed into the final product.

References

• Nexcycle Plastics Inc.: Thermoplastics vs Thermosets
• Society of Plastic Engineers Mid-Michigan Section: Thermoplastics and Thermosetting Polymers
• University of Wisconsin Stevens Point: Thermoplastics and Thermosets
• University of Bolton: Differences Between Thermoplastics and Thermosets

Resources

• National Geographic Society: Polymers: They're Everywhere!