Polymers are macromolecules composed of repeating subunits called monomers. These monomers are linked together by covalent bonds, where atoms share electrons, forming a strong union. The process of creating a polymer is known as polymerization.

Thermoplastic polymers play a crucial role in Additive Manufacturing. These polymers soften when heated and harden as they cool. They are commonly used in plastic 3D printing, especially in Selective Laser Sintering (SLS). Several notable thermoplastics can be utilized in this process, each offering varying results based on their inherent properties.