9701 · 35.3
Degradable polymers
Most everyday plastics are like super-strong chains that never break, causing massive pollution. Degradable polymers have special weak links built in, allowing them to be broken down by water or light into harmless smaller molecules.
Need to know
What you need to know
- Polyalkenes have non-polar C-C and C-H bonds.
- These bonds are strong and not susceptible to nucleophilic attack or hydrolysis.
- Microorganisms cannot break them down, so they persist in landfill and natural habitats for centuries.
Explanation
Breaking Down Plastics
- Non-biodegradable polyalkenes, with their strong, non-polar C-C backbones, are chemically inert and persist for centuries in landfill or oceans.
- Biodegradable polymers contain hydrolysable links, such as ester or amide groups. These polar groups are susceptible to attack by water, often catalysed by acids, bases, or enzymes.
- Photodegradable polymers incorporate carbonyl (C=O) groups into their backbone. These groups absorb UV radiation, providing the energy to break adjacent C-C bonds and fragment the polymer chain.
- There is a trade-off between a polymer's durability for its intended use and its ability to degrade afterwards. The choice between recycling, composting, or using degradable materials depends on the specific application and environmental impact.