Plastic Knowledge Base

Plastic is a common name for Polymers: materials made of long strings of carbon and other elements. Each unit in a string is called a monomer, and is a chemical usually derived from oil.

The monomer is made into polymer by chain-linking reactions. This is like making a daisy chain. Instead of flowers, carbon atoms are joined together. The appearance of the daisy chain will be different if you use different coloured flowers, and so will polymers.

There are many different types of plastic, depending on the starting monomer selected, the length of polymer chains, and the type of modifying compounds added. Each plastic has been developed for a special purpose.

Plastic is all around us. It forms much of the packaging for our food and drink. For many of us, it is throughout shops, our home, our workplace, our car and the bus we take to and from work. It can be in our clothing, shoes, building, eyeglasses, teeth, computers, phones, dishes, utensils, toys. The list goes on, no endless.

Plastic is versatile, lightweight, flexible, moisture resistant, durable, strong and relatively inexpensive. It can be chemical resistant, clear or opaque, and practically unbreakable. These are wonderful useful qualities, and plastic plays many important roles in life on Earth, but the widespread use of plastic is also causing unprecedented environmental problems, and harbours serious health risks – especially for children. Plastic should be used wisely, with caution and only when suitable alternatives do not exist or are not available.

There are two main groups of plastics:

1. THERMOPLASTICS soften with heat and harden with cooling.

Some typical thermoplastics are:
Acrylic (Perspex)
Acrylo-nitrile (Nylon)
Polyethylene (Polythene)
Polypropylene
Poly Vinyl Acetate (PVA)
Poly Vinyl Chloride (PVC)
Polystyrene and ABS
PTFE (Teflon)

2. THERMOSETS are cured or hardened by heat.

Some typical thermosets are:
Bakelite
Epoxy
Melamine
Polyester
Polyurethane
Properties

Plastics are used because they are:
Attractive
Hard and slippery
Soft and rubbery
Tough and slippery
Flexible
Good insulators of heat or electricity
Light weight
Hygienic
Non-rusting
Easy to shape and colour
Cheap