PETG is the most famous copolymer used in the 3D printing world. Its appearance is due to the combination of PET with glycol, improving the interesting properties of PET with a glycolization process.
PET (Polyethylene terephthalate) was created in 1941 by British scientists Whinfield and Dickson, who patented this polymer for the manufacture of fibers that would replace cotton fibers. In 1946, this material, in the form of a fiber, became established in the industry and its use in the textile sector is still at the forefront today. At the beginning of 1952, PET began to be used in film form for food packaging, but it was in 1976 that this polymer reached its peak with the manufacture of rigid bottles for beverages that are not very sensitive to oxygen, such as carbonated soft drinks, beer and mineral water. It is not surprising that PET is the most widely used plastic in the world.
PETG is the result of the copolymerization of PET. The process is based on adding cyclohexane dimethanol (CHDM) instead of ethylene glycol, achieving a longer block of atoms, where the neighboring chains do not fit together as ethylene glycol does. This slows down crystallization when stress is applied to this material, makes it more translucent and reduces its melting point, ideal characteristics for creating parts that are resistant and easy to thermoform or extrude. Due to the ease of extrusion and thermal stability, PETG and other PET derivatives are being used more and more frequently in the world of FDM/FFF 3D printing.