A thermoset is a type of polymer that, once cured or hardened through a chemical process, cannot be remolded or reshaped. This property is due to the cross-linking of polymer chains during the curing process, which creates a rigid structure. Common examples of thermosets include epoxy, phenolic, and polyester resins, often used in applications requiring durability and heat resistance. Thermosets are widely used in various industries, including automotive, aerospace, and electronics, due to their excellent mechanical properties and thermal stability. Unlike thermoplastics, which can be melted and reshaped, thermosets maintain their form and strength even under high temperatures, making them ideal for demanding applications.