Polymers

Polymers

1. Alkenes can be used to make polymers. Polymers are very large molecules made when many smaller molecules join together, end-to-end. The smaller molecules are called monomers

2. kenes can act as monomers because they have a double bond: Ethene can polymerise to form poly(ethene), which is also called polythene. Propene can polymerise to form poly(propene), which is also called polypropylene.

3. lots of monomer molecules → a polymer molecule The animation shows how several chloroethene monomers can join end-to-end to make poly(chloroethene), which is also called PVC.

4. One of the useful properties of polymers is that they are unreactive, so they are suitable for storing food and chemicals safely. Unfortunately, this property makes it difficult to dispose of polymers. They can cause litter and are usually sent to landfill sites.

5. Most polymers, including poly(ethene) and poly(propene) are not biodegradable, so they may last for many years in rubbish dumps. However, it's possible to include substances such as cornstarch that cause the polymer to break down more quickly. Carrier bags and refuse bags made from such degradable polymers are available now.

6. Many polymers can be recycled. This reduces the disposal problems and the amount of crude oil used. But the different polymers must be separated from each other first, and this can be difficult and expensive to do.