Looking at our ability to unmake all types of plastic

The world’s first ‘infinite’ plastic

Some plastics that could be recycled end up in landfill because of poor facilities, or confusion about what is and isn’t recyclable (Credit: Alamy) Every year, more than 380 million tonnes of plastic is produced worldwide. That’s about the same as 2,700,000 blue whales – more than 100 times the weight of the entire blue whale population.

Every year, more than 380 million tonnes of plastic is produced worldwide. That’s about the same as 2,700,000 blue whales – more than 100 times the weight of the entire blue whale population. Just 16% of plastic waste is recycled to make new plastics, while 40% is sent to landfill, 25% to incineration and 19% is dumped.

Much of the plastic that could be recycled – such as polyethylene terephthalate (PET), which is used for bottles and other packaging – ends up in landfill. This is often due to confusion about kerbside recycling or contamination with food or other types of waste.

Other plastics – such as salad bags and other food containers – find their way to landfill because they are made up of a combination of different plastics that can’t be easily split apart in a recycling plant. Litter dropped in the street and lightweight plastics left in landfill sites or illegally dumped can be carried by the wind or washed into rivers by the rain, ending up in the ocean.

Chemical recycling is an attempt to recycle the unrecyclable. Instead of a system where some plastics are rejected because they are the wrong colour or made of composites, chemical recycling could see all types of plastic fed into an “infinite” recycling system that unmake plastics back into oil, so they can then be used to make plastic again.

The way plastic is currently recycled is more of a downward spiral than an infinite loop. Plastics are usually recycled mechanically: they are sorted, cleaned, shredded, melted and remoulded. Each time plastic is recycled this way, its quality is degraded. When the plastic is melted, the polymer chains are partially broken down, decreasing its tensile strength and viscosity, making it harder to process. The new, lower grade plastic often becomes unsuitable for use in food packaging and most plastic can be recycled a very limited number of times before it is so degraded it becomes unusable.

The emerging industry of chemical recycling aims to avoid this problem by breaking plastic down into its chemical building blocks, which can then be used for fuels or to reincarnate new plastics.

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