Thermosetting polymer
A polymer that forms a persistent crosslinked network during curing. Once cured, it cannot be melted and reshaped without degrading its structure.
Polymer cross-linking: The formation of chemical bonds between polymer chains, creating a connected network. Cross-links turn separate chains into the persistent network characteristic of cured thermosets.
Epoxy resin: A reactive resin containing epoxide groups that can be cured into a crosslinked material. Epoxy is a widely used thermosetting resin, often cured by adding a hardener.
Fiberglass: A material made from fine glass fibers, used alone or embedded in a polymer matrix. Thermosetting polyester and epoxy resins bind glass fibers in many fiberglass products.
Thermoplastic: A plastic that softens when heated and can be reshaped without chemical curing. Thermoplastics can flow again with heat; cured thermosets cannot be remelted.
Polymer waste: Discarded polymer materials and products that require management, reuse, or disposal. Thermoset products contribute to polymer waste because ordinary remelting cannot restore them as feedstock.
Curing (chemistry): A chemical or physical process that hardens a material by forming or strengthening its structure. Curing creates the thermoset network and fixes the material's final shape.
Phenol-formaldehyde resin: A thermosetting resin made by reacting phenol with formaldehyde. This early synthetic resin exemplifies thermoset formation through chemical reaction and curing.
Carbon-fiber-reinforced polymer: A composite in which carbon fibers reinforce a polymer matrix. Epoxy thermosets commonly bind carbon fibers into stiff, lightweight structural composites.
Elastomer: A polymer that can undergo large reversible deformation and return near its original shape. Elastomers emphasize recoverable stretch, while thermosets are defined by permanent network formation.
Mechanical recycling: Reprocessing waste materials through physical operations such as sorting, grinding, and remolding. Grinding can recover thermoset filler or fragments, but the original network cannot simply be melted and remolded.