Why polymers are used so much
When food was taken out of the house in the past, it was wrapped in something natural, such as a banana leaf or a sheath of a plant. Today it is usually carried in a kind of polythene, a synthetic polymer. In the same way, synthetic polymers are now widely used as substitutes for natural materials.
Products made from polymers are used widely because of qualities like these:
Made to order
They can be manufactured with the properties needed.
Easy to use
They are convenient to use.
Any shape
They can be made in many shapes.
Any colour, low cost
They can be coloured in any colour, and they are cheap.
Assignment 14.4
List the things made from polymers that are used in your home.
For example: buckets and basins, water pipes and tanks, electrical wire insulation and switches, polythene bags and food boxes, non-stick pans, toothbrushes, rubber slippers, clothes of nylon or polyester, and the tyres of a bicycle.
Why they replaced natural materials
A banana leaf does its job well, but it tears, wilts in a day and cannot be made in any size we want. A polymer can be designed: choose the monomer and the chain structure, and you choose whether it is soft or hard, clear or coloured, flexible like a bag or rigid like a crate. Polymers are light, they do not rust like iron or rot like wood, they are waterproof and they insulate electricity. Once the factory is running, they are also very cheap to make in huge numbers. Every one of these advantages, as the next page shows, comes with a matching problem.
Why polymers are everywhere
Synthetic polymers can be made with the properties needed, in any shape and colour, cheaply and conveniently — so they have replaced many natural materials.