Thermoplastics are polymers that can be reprocessed since they lack chemical bonds between macromolecules.
They are divided into two based on the arrangement of macromolecules. If the molecules are arranged randomly, the material becomes amorphous. The crystalline structure is formed if the molecules are arranged regularly.
Most commercial polymers are amorphous. Amorphous materials are transparent unless additives are added. In some thermoplastics, the arrangement of macromolecules contains an order. Such thermoplastics are referred to as “semi-crystalline”. In plastics, macromolecules have a complex and entangled structure.
This hinders plastic materials from having a 100% crystalline structure. For this reason, they exist in amorphous parts among crystalline parts of plastic materials. In general, parts can be made by a range of polymer processing techniques, such as injection molding and extrusion.
The raw material of thermoplastics is more costly than that of thermosets. Thermoplastics that soften easily under heat and pressure can be reused through recycling. Polyethylene (PE), Polypropylene (PP), Polystyrene (PS), Polyethylene Ether Phthalate (PET), Polycarbonate (PC), Polyamide (PA), Acrylonitrile Butadiene Styrene (ABS), Styrene Acrylonitrile (SAN), Ethylene Vinyl Acetate (EVA), Polylactic Acid (PLA), Polymethylmethacrylate (PMMA), Polyvinylchloride (PVC), Thermoplastic Polyurethane (TPU), Acrylonitrile Styrene Acrylate (ASA), Polyoxymethylene (POM), etc. are a part of this group.