Termosetti

Terimosetti, or thermosets, are a class of polymers that irreversibly cure to form a rigid three‑dimensional network. This curing is achieved through crosslinking reactions that can be initiated by heat, catalysts, or radiation, creating a permanently set material. Once cured, thermosets do not melt; they may soften only slightly and will decompose at sufficiently high temperatures.

The curing chemistry of thermosets falls mainly into two categories. Addition curing involves reactions that form covalent bonds without byproducts, as seen in epoxies and some polyurethanes. Condensation curing releases small molecules such as water or alcohol during crosslinking, as with phenolic resins and melamine-formaldehyde resins. The resulting network imparts high thermal stability, chemical resistance, and dimensional rigidity, but once formed, the material cannot be reshaped by heating.

Processing and properties of termosetti are shaped by the network structure and crosslink density. They typically exhibit high modulus, strength, and heat resistance, along with excellent electrical insulation in many formulations. They can be brittle and less impact-tolerant than some thermoplastics, and their processing windows depend on cure kinetics and heat transfer. Recyclability is challenging because the crosslinked structure cannot be remelted and reprocessed.

Common families include epoxies, phenolics, polyurethanes, silicones, and unsaturated polyesters. Applications span coatings, adhesives, electrical and electronic encapsulation, and reinforced composites in automotive, aerospace, and consumer electronics. End-of-life options are limited, often focusing on reuse of parts, grinding for fillers, or energy recovery rather than conventional recycling.