Duroplaste

Duroplaste are polymers that undergo a chemical curing process to form a three-dimensional, crosslinked network. Once cured, they do not melt or flow with heat. This irreversible setting distinguishes them from thermoplastics. Duroplaste are typically formed by condensation or addition reactions that create strong covalent bonds between chains, using crosslinking agents such as phenolics, epoxies, isocyanates, or anhydrides, and curing conditions including heat, pressure, or catalysts.

Properties: The resulting materials exhibit high dimensional stability, excellent thermal resistance, chemical resistance, and very good electrical insulation. They can maintain mechanical strength at elevated temperatures and are often inherently rigid. However, they are usually more brittle and have lower impact resistance and fracture toughness than many thermoplastics. The crosslinked network also makes recycling and remolding difficult; processing typically ends with a cured part or composite, though some chemical or mechanical reclamation methods exist for certain formulations.

Applications: Duroplaste are widely used in electrical insulation and encapsulation (potting compounds), protective coatings, and as matrices for fiber-reinforced composites (laminates in aerospace, automotive, and construction). Common families include phenolic resins, amino resins, unsaturated polyesters, epoxies, and certain polyurethanes.

Processing methods: Common processing routes include molding (compression, transfer) and casting, as well as prepreg and filament-winding techniques for composites. Cure conditions vary by system, encompassing heat, catalysts, or UV exposure in specialized resins.