A Brief Introduction to Plastic and Types of Plastic
Plastic as a term refers to a range of synthetic (or sometimes semi-synthetic) materials, almost invariably solid, mostly with industrial applications. Usually polymers (that is large chains of molecules) with a high molecular mass; sometimes other substances are introduced to reduce the cost of production.
The usefulness of plastic is told in its name: plastic comes from the Greek “plastikos”, which means “capable of being moulded.” This capability means that plastic can be cast into an almost infinite variety of different shapes, with no regard for size, and yet it will harden and become firm and durable. Some useful shapes include fibres and films, plates, tubes, bottles and boxes, and many more.
Due to the relatively low cost of production involved, and the ease of which they can be manufactured, plastics are used in a wide variety of products. They are versatile and durable, and therefore have already replaced many traditional construction materials, such as leather, wood, stone, bone, metal, ceramics and glass.
There are two main types of plastics: thermoplastics and thermosetting plastics. Thermoplastics don’t go through a change when they are heated, and so they can be moulded over and over again once they reach temperature (hence the name’s thermo prefix). Thermosetting plastics stay solid permanently once they have set (hence the setting); they can obviously be melted again, but cannot be reformed.
Alexander Parkes, a British engineer, invented the first artificial plastic in the mid nineteenth century. Naming the material Parkesine, Parkes demonstrated that his creation could be heated, moulded, and cooled, retaining its shape once it had set. Parkesine was a long way from the plastics we know today; it was extremely flammable, expensive, and prone to cracking. Plastics developed over the remainder of the century, although it was not particularly a widely used material until the middle of the next century.
Plastics are durable, but they do degrade very slowly. The molecular bonds that make plastics so durable are the reason for their durability. Billions of tonnes of plastic have been dumped since the middle of the twentieth century, a large portion of which will still be around in many thousands of years. Producing plastics can create pollutant chemicals, and burning plastics often produce noxious fumes that are usually poisonous. However, plastics are widely recyclable, especially in the more developed countries where they are produced en masse, meaning that plastics can be used more widely and more ethically than ever before.
One of the more widely used methods of moulding plastic is injection moulding. plastic manufacturers are in massive demand, as plastic is an efficient and durable industrial material.
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