Thermosetting plastics are a type of polymer that, once cured or hardened, cannot be remolded or reshaped. This process involves a chemical reaction that creates a strong, inflexible structure. Common examples include epoxy, melamine, and phenolic resins, which are often used in applications requiring durability and heat resistance. These materials are widely used in various industries, including automotive, electronics, and construction, due to their excellent mechanical properties and resistance to chemicals and heat. Unlike thermoplastics, which can be melted and reshaped, thermosetting plastics maintain their form and strength even under extreme conditions.