In the simplest terms, a polymer is a substance made up of many repeating units. You can think of it as a chain, where each individual link is a "mer"—a basic chemical unit composed of carbon, hydrogen, oxygen, and/or silicon. When these links are hooked together chemically, the process is called polymerization.
Thermosets (traditionally referred to as Duroplastics) are polymers that undergo a permanent chemical change while they are being formed. They react through processes called polycondensation and cross-linking to create a rigid, three-dimensional lattice structure.
No. The process of forming a thermoset is called curing, which involves an irreversible structural change at the molecular level. Once a thermoset plastic has achieved its final shape, it cannot be melted down, reformed, or recycled into a new shape.
Common examples of thermosets include:
Polyester resins
Epoxies
Polyurethanes
Silicones
Phenolic resins, melamines, and urea resins
