Polymers are very big molecules with long chains and they are made from many small molecules called monomers. Poly- means many, mono- means one. You can get the name of the polymer if you add the prefix poly- before the name of the monomer. For example, poly(propene) is used to make ropes; lots of propene molecules form a long chain.
The reaction during which polymers are made is called polymerisation and high pressure and a catalyst are needed for it to occur. Catalysts are chemicals that speed up a reaction without being used in it.
Monomers have a double bond between their carbon atoms, but the corresponding polymer has only single bonds. Therefore, polymers can only be saturated (compounds with single bonds only). Look at the diagram showing ethene and poly(ethene):
Hydrocarbons are compounds made of hydrogen and carbon only. Monomers are hydrocarbons. There are two types of hydrocarbons: alkanes (single bonds, saturated) and alkenes (double bonds, unsaturated). The simplest alkane is methane, CH4. As you can see, it has one carbon atom and four hydrogen atoms. Bromine solution is used to test whether a hydrocarbon is saturated or not. Bromine solution is orange. Alkanes do not react with it so the solution remains orange. However, alkenes do react with it, so it turns colourless. In other words, bromine solution 'detects' double bonds.
- PVC, poly(vinylchloride), is a waterproof polymer. It is also flexible and used to make raincoats.
- Poly(ethene) is waterproof and flexible and used to make plastic bags.
- Poly(styrene) is an insulator and absorbs shock, so it is used in packaging fragile products.
- Poly(propylene) is strong and flexible and used to make ropes.
- GORE-TEX is another polymer that is suitable for clothing for an active lifestyle and outdoor activities. It is waterproof and flexible, but what makes it unique is that it is also breathable, which means it allows sweat to pass through it, so it does not condense on the inside of clothes.
Biodegradable polymers - which dissolve - are now made to protect the environment.