PVC is a thermosetting plastic

A guide through the plastic world

Thermoplastics

Whether at the deposit machine, in the stationery store or in the electronics retailer - we encounter plastics that are thermoplastics everywhere. Anyone who has ever filled a PET bottle with hot water or left plastic packaging too close to the grill knows: Thermoplastics become malleable when they are heated; they melt when exposed to extreme heat. They retain their new shape after cooling, but can theoretically be deformed as often as required by reheating. Most of the plastics made and used today fall under this category.

Thermoplastics include materials such as polyethylene (PE), which is the most widely used plastic in the world. While low-density PE (LDPE) is mainly used for foils and other thin-layer products, the somewhat more stable materials of the HDPE group are known, for example, from bottles for household cleaning agents and larger containers such as waste bins.

Polypropylene (PP) is also often used for packaging. Its most important property is its resistance to fatigue fractures, so that, for example, glasses cases with a PP connection between the two shell parts can be bent over and over again without breaking.

Polyamide (PA) is mainly used for textiles, but also for the covering of tennis rackets. The material has a very smooth surface and has high tensile strength.

Polyethylene terephthalate (PET) is mainly known from PET bottles, but it is also used as a textile fiber under the name polyester in many everyday objects - for example films or textile fibers.

Other known thermoplastics are polycarbonate (PC), which is used in eyeglass lenses, solar modules and protective helmets, polystyrene (PS), which is known as a foamed insulation material, or polyvinyl chloride (PVC), which is used in pipes and floor coverings. The main group of thermoplastics therefore includes a large number of properties and areas of application. When you mix two or more thermoplastics together to obtain a material with new properties, the result is called a polyblend.

Thermosets

Duroplasts are chemically hardened once during their production and then retain their shape even when heated. Too much heat, however, decomposes the material and makes it brittle. Duroplasts are mostly used where they can prove their stability even under strongly fluctuating temperatures, for example in electrical installations or outdoors.

They are known in everyday life, for example, from pedal boat cladding or play equipment on the children's playground. Well-known types of thermosets are polyester resins, but also the first industrially manufactured plastic Bakelite - from which antique telephones were made - or polyurethane resins, which are found in paints, for example.

Elastomers

Elastomers survive heating undamaged and can change their shape under pressure or stretching, only to return to their original state afterwards - rubber bands that are used in the home or office are an example of this. The starting material is rubber, a natural product that is made permanently elastic, for example by vulcanization with sulfur. Car or bicycle tires are also made of elastomers.