Plastics can be:
- Natural:
They are obtained directly from vegetable raw materials (e.g. cellulose, cellophane and latex) or animal raw materials (e.g. casein, one of the main proteins in cow's milk).
- Synthetic or artificial:
They are made from compounds derived from petroleum, natural gas or coal. Most plastics belong to this group.
The industrial transformation of these raw materials and compounds into plastics is called polymerization.
- During the manufacture of plastics, so-called fillers are added.
These are materials such as glass fiber, textile fibers, paper, silica, mineral powder or sawdust, which, in addition to reducing production costs, enhance certain properties of the raw material or initial compounds.
- Some additives (chemicals) are also incorporated, such as plasticizers to increase the flexibility and strength of the polymer, or pigments to give the plastics a certain color.