The Polystyrene (PS) is a ermoplástico polymer obtained from the polymerization of the styrene .
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- 1 History
- 2 Description
- 3 Obtaining
- 4 Properties
- 5 Types of Polystyrene
- 6 Applications
- 7 Sources
Polystyrene was first obtained in Germany by the IG Farbenindustrie in 1930. The most widely used process today for its manufacture is “mass polymerization”, the emulsion and solution processes having become obsolete.
The polymerization of pure styrene results in a pure polystyrene that is a colorless, rigid, brittle solid with limited flexibility. This pure polystyrene is called ” Crystal Polystyrene ” or “General Purpose Polystyrene” (General Purpose Polystyrene, GPPS). Below 95 ºC (glass transition temperature of polystyrene), the crystal polystyrene is Vitreous , above that temperature aC softer and can be molded. Recently, a new class of polystyrene has been developed, which is called Syndiotactic.. It is different because the phenyl groups in the polymer chain are alternatively attached to both sides of it. The “new” polystyrene is crystalline and melts at 270 ºC, but it is much more expensive. It is only used in special applications with high added value.
Polystyrene is a polymer that is obtained by a process called polymerization, which consists of the union of many small molecules to achieve very large molecules. The obtained substance is a polymer and the simple compounds from which they are obtained are called Monomers .
Keep in mind that, in addition to the covalent bonds that hold together the molecules of the monomers , other intermolecular interactions and intramolecular that strongly influence the physical properties of the polymer, which are different from those of the starting molecules typically occur . Polystyrene, in general, has elasticity, some resistance to chemical attack, good mechanical, thermal and electrical resistance and low density.
Types of Polystyrene
There are four main types: PS glass , which is transparent, rigid, and brittle; the high impact polystyrene , resistant and opaque, the expanded polystyrene , very light, and the extruded polystyrene , similar to the expanded but more dense and waterproof.
The main advantages of polystyrene are its ease of use and its relatively low cost. Its main disadvantages are its low resistance to high temperature (it deforms to less than 100 ° C, except in the case of syndiotactic polystyrene) and its modest mechanical resistance. These advantages and disadvantages determine the applications of the different types of polystyrene.