Termostetting

Ter­mostetting, also referred to as thermosetting in English, describes polymers that irreversibly cross-link to form a rigid, three-dimensional network. The curing process is driven by heat and/or chemical reactions such as condensation or addition, and once cured the material cannot be melted or reshaped by reheating. This distinguishes ter­mostetting materials from thermoplastics, which soften when heated.

Curing chemistries include addition curing (for example epoxies, polyurethanes, and silicones) and condensation curing (such as phenolics and melamines). Typical ter­mostetting resins include epoxy, phenolic, silicon, polyurethane, and unsaturated polyester resins. Cure can involve mixing a resin with a hardener or catalyst and applying a controlled temperature profile; some systems cure at room temperature while others require elevated temperatures.

Processing and manufacturing often involve molding, casting, or impregnation of fibers in composites. After combining resin and hardener, a cure cycle is applied to achieve full cross-linking. Post-curing can improve heat resistance and mechanical properties but reduces the potential for reshaping.

Properties of cured ter­mostetting materials include high thermal stability, chemical resistance, stiffness, and dimensional stability. They are typically resistant to solvents and heat but can be brittle and challenging to repair or recycle due to the cross-linked network. Reprocessing by melting is not feasible; recycling approaches include chemical depolymerization, energy recovery, or recycling of composite components.

Common applications include electronics encapsulation and potting, structural composites (fiber-reinforced polymers), coatings and adhesives, automotive and aerospace parts, and durable consumer products requiring heat resistance and long-term stability.