Plastics are chemical compounds produced through unnatural chemical processes. Plastic is a raw material composed of very large molecules, which arise through synthesis from biological materials. The raw materials of ‘plastic chemistry’ are hydrocarbons, made from oil refining. These raw materials form covalent or ionic bonds during the chemical synthesis, resulting in amorphous or crystalline substances.
Applications of Plastics
Plastics have a wide range of applications, including:
Some examples:
- Garden furniture
- Tiles
- Clothing
- Packaging boxes
- Bottles
- Bins
Processing of Plastics
Thermoplastics used in packaging are manufactured through blow molding (such as the translucent containers for milk or juice at the supermarket), injection molding (such as ice cube trays), extrusion (such as tubes and profiles), vacuum forming (flowerpots, coffee cups), and rotational molding (e.g., a slide).
PVC is used, among other things, for the manufacture of plastic window frames. These frames are recycled after use, and the plastic pellets are then used for the production of plastic ground and water barriers, such as bulkheads and dam walls.
Types of Plastics
There are three types of plastics:
- Thermoplastics
- Thermosets
- Elastomers
Thermosets and elastomers are raw materials that are only processed into a product once. Heating again results in decomposition.
Plastics are sometimes reinforced, for example with fiberglass or with synthetic fibers such as Kevlar, Twaron, and Dyneema.
Natural vs. Artificial Polymers
Examples of natural polymers include cellulose, rubber, and polylactic acid. Examples of artificial polymers include aramid, Bakelite, nylon, polyester, polyethylene, polyethylene terephthalate, polyethylene terephthalate glycol, polyisocyanurate, polymethyl methacrylate, polypropylene, polystyrene, polyurethane, polyvinyl chloride, polytetrafluoroethylene, and polycarbonate.
