Processes

How is polystyrene made ... and processed?

The building block - monomer - of polystyrene is styrene. The raw materials to make styrene are obtained from crude oil. A range of processes such as distillation, steam-cracking and dehydration are required to transform the crude oil into styrene. At the end polystyrene is produced by polymerising styrene. The final product is available in the form of pellets. In order to get the final articles polystyrene pellets are extruded, thermoformed or injection moulded. Extrusion is a process in which the pelletised polymer is melted and then forced continuously through a die to form an endless profile of polymer. Most of the time polystyrene is extruded into sheet. In a second step this sheet can be thermoformed into the final article. Applications of thermoformed articles include disposables such as cups and plates, meat and poultry trays, multiple and single-serving food containers in dairy, vending machine cups, trays for hospital and restaurant use. Injection moulding is a process by which polymer is melted and injected in a mould cavity, which after cooling down solidifies into the shape of the mould. Typical injection moulding applications are housing of televisions, jewel boxes for compact discs, toys and innumerable other uses.

Did you know ?
  • South African researchers developed a barrier made from plastic which protects bathers without harming the sharks.
  •  
  •  
  •