Duroplastic, also known as thermosetting plastic, refers to a type of polymer that, once set into a given shape through heat and/or pressure, cannot be remolded or reshaped. This property is due to the chemical cross-linking that occurs during the curing process, which makes the material rigid and heat-resistant. Common examples of duroplastic materials include epoxy resins, phenolic resins, and melamine formaldehyde. These materials are often used in applications requiring durability, such as electrical insulators and automotive components.