What are the challenges in recycling polymers?

Recycling polymers is challenging due to their diverse types, the presence of additives, and the energy-intensive recycling process.

Polymers come in a wide variety of types, each with different properties and structures. This diversity makes it difficult to sort and separate them for recycling. For instance, polyethylene terephthalate (PET) and high-density polyethylene (HDPE) are both types of plastic, but they cannot be recycled together due to their different chemical structures. Therefore, they must be separated, which can be a time-consuming and costly process.

Another challenge is the presence of additives in polymers. These can include colourants, plasticisers, and flame retardants, which are added to give the polymer specific properties. However, these additives can complicate the recycling process. For example, they can interfere with the melting and reshaping of the polymer, or they can produce harmful substances when heated. Removing these additives before recycling can be difficult and expensive.

The recycling process itself can also be energy-intensive. Polymers need to be collected, sorted, cleaned, and then heated to high temperatures to be reshaped. This requires a significant amount of energy, which can contribute to environmental problems such as climate change if it comes from non-renewable sources. Furthermore, the quality of recycled polymers can be lower than that of virgin polymers, which can limit their applications and make recycling less economically viable.

Lastly, there is the issue of consumer behaviour. Many people do not recycle their plastic waste properly, either because they are not aware of how to do it or because they do not have access to recycling facilities. This results in a large amount of plastic waste that ends up in landfill or in the environment, where it can cause harm to wildlife and ecosystems. Therefore, education and infrastructure are important factors in overcoming the challenges of polymer recycling.