finished plexiglass lid
What are plastics?
Plastics as we broadly understand it today are synthetic or semi synthetic products or raw materials, formed by polymerisation, and are largely derived from oil. Polymerisation is the formation of polymers i.e. repeated numbers of smaller structures (monomers) joined together.
It wasn’t until the 1860s that the first semi synthetic materials or plastics were first brought to the attention of the world, and since the development of thermoplastics throughout the 1900s it’s hard to imagine how difficult life would be without plastic. The main reasons why plastics replaced more traditional materials are quite straightforward when you think about them.
What’s so good about plastics?
Plastics are relatively light and very durable. The hundreds of different plastic varieties are ultimately recyclable, although it’s only in recent years that our UK society has begun to take advantage of plastic recycling, often in tandem with our weekly waste collections. Plastics have great thermal and insulating properties (clothes, carpets, bedding etc). Plastics are resistant to many chemicals and water, as well as being very strong.
Most notably though, plastics have proven relatively inexpensive to produce, and are so versatile that they can take on almost any form and colour.
What are the popular types of plastics and what’s the difference between them?
These were developed in the 1930s. Acrylics are particularly resistant to the weather and the sun. Acrylic is particularly effective as ‘clear’ plastics, and transmits light brilliantly. Applications include leaflet holders, signs, display cases, boat windows and point of sale to name but a few.
Often wrongly spelled as Plexiglass, Plexiglas is actually a brand name for a kind of clear thermoplastic resin that’s basically a cross between acrylic and polycarbonate.
First developed in the 1950s, these thermoplastics most popularly have engineering applications. This is due to polycarbonate’s strength coupled with versatility, and its electrical insulating properties. Applications include machine guards, capacitors, gaskets etc.
This is a variety of polycarbonate. It is popularly developed in sheet form and is widely recognised as a kind of ‘clear’ plastic.
Another plastic developed in the 1950s with industrial applications, this is particularly suitable for hot fill packaging because it has low density but is very rigid. Other applications include carpeting and packaging.
Poly Vinyl Chloride (PVC) can be shaped and moulded into an exceptionally wide variety of products. Chemical Plant Industry applications of PVC include water tight tanks, and ducting for Clean Air Systems.
Polyethylene Terephalate Glycol (PETG) is another industrial thermoplastic. Applications include frames, sign holders and point of purchase displays.
How it takes shape
Modern advances in plastic fabrication, moulding, casting, extrusion, thermoforming, cutting, bending, machining, gluing, welding, stamping of sheets, plastic engraving, fibres and solid blocks mean that our imagination provides the only real limitations to what form plastics can take.
If you asked most people, they would be unlikely to know what plastics actually are, and even more unlikely to be able to tell you the difference between the many types. Despite this, plastics are a central and essential part of modern daily life.