Энциклопедия
Pure polystyrene is a colourless, hard and breakable thermoplastic, which is a material formed by melting. Isi s characterized by limited elasticity and high rigidity.
When mixed with admixtures, it constitutes a basis to many plastics. Products manufactured from this material are marked with PS letters.
Polystyrene, as a plastic, may have a colourless, slightly transparent or dyed to bright colours form. In comparison to polyethylene and polypropylene, it has lower temperature of softening and lower viscosity. This qualities guarantee easier production of small object with complex shapes with the use of this material.
This material is used for the production of: toothbrushes, artificial jewellery, CD boxes, elements of toys, mugs, various packaging (with exception of food packaging – PS has too low chemical resistance).
However, the most popular use of polystyrene is the production of its foamed form, popularly called styrofoam. It is broadly used for the production of building insulating boards, as well as various types of packaging.
PETG – a kind of thermoplastic polyester resin from PET family. Because of the admixture of glycol, it is perfect for the production of transparent packaging and other products by embossment method.
PETG is characterized by very good reflective qualities, high transparency and gloss. This is why it is used for the production of various types of foils (rigid, flexible), shapes, pipes and bottles (with exception of pressure bottles).
There are many possibilities of decoration of this material. It can be dyed to any colour with the use of colouring concentrates, metallized (e.g. Christmas tree decorations) or overprinted.
Thanks to its features, PETG is used in pharmaceutics, cosmetics, publicity and branch of packaging.
Polyvinyl chloride is a plastic that has thermoplastic features. It is characterized by high mechanical performance and resistance to many dissolvents.
PVC is used in many branches of industry, in medicine (syringes, catheters), in electrotechnics (wire insulation) or in the branch of packaging. Gramophone records, elements of appliances, floor finishes, decorative banding, foils, electro-insulations and other products are made of it.
PCW is divided according to the method of production into hard and plastified one, and with regard to technology – to suspensive and emulsion PCW.
Hard PCW is highly chemically resistant, it is easy to glue or weld and it is almost entirely incombustible (it burns only superficially and it quickly dies down, as it contains a large amount of chloride). It does not react to acids, bases, mineral alcohols and fuel, and in connection with benzene or aether, it swells.
All types of PCW are susceptible to foaming.
In Poland, the PCV abbreviation is commonly used, which is incorrect. Instead of it, in Poland the PCW abbreviation should be used, and in the world – PVC.
Polyethylene terephthalate – a popular plastic characterized with high endurance, ductility and perfect machinability. PET is light and resistant to cracking, so the objects made of it are very practical.
Thanks to these qualities, PET is used very broadly. It is used for the production of packaging, dishes and elements of electrical appliances. It also serves for the production of fibres from which the popular polartec - fleece is made. This material is very often used for the production of bottles, e.g. for water, carbonated drinks, juices, eatable oils, but also for various types of cleaning agents.
The most important advantage of PET material is the discretion in its forming, which enables the production of every shape of packaging (e.g. original bottle or jar). Polyethylene terephthalate gives one also a free choice when it comes to dyeing and it is highly transparent.
PET is characterized also by: big hardness and rigidity, high chemical resistance, low water absorptiveness, high mechanical and heat durability, resistance to atmospheric factors and corrosion. Another important thing is the fact that PET has high impact resistance and stability of shapes, good sliding features and that is has a foodstuff quality.
Polyethylene terephthalate was used for the first time in 1941 by British Calico Printers (for the production of synthetic fibres). In the middle of 1960s, it started to be used for the production of foils (photography, video tapes, plates, X-ray pictures, packaging), and in 1970s the production of bottles was started.
PET material can be identified by the fact that it burns with sooty flame, but it does not have a characteristic smell of hyacinth. It does not dissolve in typical dissolvents.
Polypropylene is one of the most often used plastics. The objects made from this material are marked with PP symbol.
Polypropylene belongs to the group of hydrocarbon thermoplastic polymers. It changes its aggregate state (from liquid to solid and the other way round)not changing its chemical properties.
In industry, the isotactic form of PP which is more rigid, better to process and more resistant to bending and tearing in comparison to the polyethylene is used the most often. Unfortunately, it is also more expensive and has lower chemical resistance than polyethylene.
The first production of isotactic PP was launched in 1957 in Italy.
Polypropylene is characterized by high chemical resistance, it is almost entirely resistant to acids, bases, sals and organic solvents. It is permeable to air, it is physiologically neutral and easy to process (up to 270°C). PP is a burnable, colourless, odourless and resistant to water material.
The disadvantages of polypropylene and its composites are e.g. too low temperature of usage (−5 to +100 °C) and low resistance to oxygen and UV radiation (it results in the necessity to use anti-oxidants and stabilizers).
PP is broadly used in the following industries: chemical, pharmaceutical, textile, electrotechnical, motor, building, furniture and food. Toys, household appliances and different types of packaging are also made of it.
Polyethylene is a relatively soft, flexible, transparent material. It is easily dyed on a given colour.
For the first time it was produced by a British company Imperial Chemical Industries in 1933.
It looks like a hard paraffin, it bends when touched by finger. It melts and burns. When it is extinguished, one can smell a characteristic odour of paraffin. It may be processed by the use of all known methods.
Products made of PE are characterized by low permeability for water vapour, they are permeable for steams of organic substances, they are not resistant to hydrocarbons and their chloride derivatives. However, they are resistant to solutions of acids, bases and sals and low temperature. Polyethylene is used for the production of: foils, pipes, containers, skis and sails.
It exists in two forms: high-pressure (LDPE) and low-pressure (HDPE).
