What are the two major categories of resins used in composites?

The correct answer identifies the two major categories of resins used in composites as thermoset and thermoplastic. Understanding these categories is important in the field of composite materials, as they significantly influence the properties and applications of the composites being created.

Thermoset resins, such as epoxy and polyester, undergo a chemical change when they are cured, which means they cannot be remolded or reheated after they have set. This results in a material that is rigid and dimensionally stable at elevated temperatures, making thermosets ideal for applications requiring durability and strength.

On the other hand, thermoplastic resins are different in that they can be reheated and remolded without undergoing any chemical change. This characteristic allows for greater flexibility in manufacturing and recycling processes, enabling easier fabrication and repair of composite materials. Thermoplastics can also offer enhanced impact resistance and lower processing temperatures.

By categorizing resins in this manner, one can understand the different properties and performance characteristics they lend to composite materials, which is crucial for selecting the appropriate resin for specific applications in industries such as marine, automotive, and aerospace.