Disposing of Polymers
- Though poly(alkenes)s are extremely important in everyday such as their use as plastics, the disposal of these polymers is problematic
- Poly(alkenes) are very large alkane molecules which are unreactive and therefore do not undergo any chemical reactions; they are resistant to chemical attack
- Due to their unreactivity, polymers are non-biodegradable and take up to hundreds of years to decompose when dumped in landfill sites
- Throwing away poly(alkenes) therefore cause the long-term pollution of the environment
- Burning the polymers results in harmful combustion products which again cause the pollution of the environment
Examiner Tip
The disposal of polymers is a challenge due to their unreactivity, their non-biodegradability, and the formation of harmful combustion products when burnt.
Solutions to Plastic Pollution
- Possibly the easiest method to reduce the amount of plastic, is to reuse it rather than throwing it away
- Since polymers have a long chain full of saturated, non polar C-C bonds
- This makes them very unreactive molecules, which is why they are said to be non-biodegradable
- They cannot be attacked and broken down by biological agents, such as enzymes
- This is what makes throwing plastic away to end up on a landfill such a problem
- Instead of throwing it away or reusing the plastic, you could recycle it
Feedstock Recycling
- This is one possible solution to deal with the excess pollution that is caused by plastic
- This process involves
- Heating the plastic to a high enough temperature that the polymer bonds break, and monomers are formed
- The monomers formed are then used to produce new plastics
Mechanical Recycling
- This is a more straight forward type of recycling
- The different types of plastic are separated and washed thoroughly
- Then, they are ground up into small pellets
- The pellets are heated up until they melt, and then remoulded so that they can be used again
Some Issues
- These types of recycling are not perfect solutions
- Some plastics, like poly(propene), can only be heated and reused a number of times
- Each time the plastic is heated, some of the key chains break
- This means that over time, the properties of the plastic are degraded
