July 23, 2021
Polymers are useful in our daily life, but do they do harm to us? Let's look at the biodegradability and disposal of polymers in A-Level Chemistry.
Polyalkenes are chemically inert due to their strong non-polar C-C backbone and C-H bonds. This measn they cannot be attacked by biological agents like enzymes, and are non-biodegradable.
Polyesters and polyamides however, can be broken down by hydrolysis and are therefore, biodegradable.
Plastics can also be recycled in three different ways:
- Mechanical recycling: plastic waste is sorted, cleaned, shredded and melted down. THe melt is usually formed into pellets which can be remoulded to make new objects. THis works for poly(propene) and HDPE.
- Chemical recylcing: does not require sorting. The waste is heated (possibly with a catalyst) to break down long carbon chains to make smaller products that can be reused. It is similar to cracking.
- Thermal recycling: the plastic waste is incinerated and heat energy produced can be used to make steam or electricity.
There are also different ways to dispose plastics:
Drafted by Eunice (Chemistry)
References
https://www.allthings.bio/dispose-bio-based-plastics/
https://www.cell.com/trends/biotechnology/fulltext/S0167-7799(20)30062-7?rss=yes