Chewing gum solvent helps recycle expanded polystyrene
06 August 2015
Researchers have developed a cost-effective and green method for recycling polystyrene packaging thanks, in part, to a solvent used in chewing gum.
“There has been a great deal of interest from the plastics sector,” says coordinator of the EU-funded Polysolve project, Antonino Furfari, who is also recycling and advocacy manager at European Plastics Recyclers (EUPR), Belgium. “It is now a question of getting industry fully behind this innovation.”
Expanded polystyrene (EPS) is often used in goods packaging and for shipping fish. By developing an efficient and environmentally friendly means of recycling old boxes, Polysolve could save industry money and alleviate pressure on landfill. The recovery and recycling method also works for polycarbonate (PC) plastic, which can be found in everyday products such as CDs and DVDs.
“The recycling streams for these two common polymers have not been as fully developed as for other polymer types such as PET (which is commonly used in plastic bottles),” says Furfari. “This is why we have developed a new recycling process capable of dissolving waste in order to obtain a high purity product.”
In this way, the innovation promises to strengthen the sustainability of various plastics, which already offer a variety of environmental benefits to manufacturers. For example, durable yet lightweight plastic parts can save weight in cars, aircraft and packaging, leading to lower transportation costs and reduced fuel consumption. PET bottle recycling is already a well-established part of everyday life in most parts of Europe.
What Polysolve has done is open the door to more integrated plastic recycling. Users of polymers with more modest track records of sustainable use – such as EPS and PC – can now recycle more of their material thanks to this new solvent process.
Furthermore, extending the solvent-based technology to other polymers could help the plastics industry to deal with high volumes of mixed polymer waste. Individual polymers could be separated and recycled to a far higher degree of purity (and consequently value) than is currently possible.
Facilities that use a great deal of EPS – such as harbours – have been encouraged to establish waste collection points. Old boxes and packaging material can then be dissolved by the Polysolve process, which uses biodegradable solvents to specifically extract polystyrene and polycarbonate from mixed waste streams, resulting in recycled polymers comparable in purity and performance to virgin material.
The process reduces both the level of non-biodegradable waste going to landfill and the pressure on non-sustainable oil-derived feedstocks for polymer manufacturing. Insoluble materials – such as metal foil and ink particles – are also filtered out.
The final purified polymer comes out as a pellet, and the ‘green’ solvent – also used in food applications such as chewing gum – then recycled. “All this makes recycling so much more financially attractive,” says Furfari. “EPS is incredibly light – most of what you are transporting is air – so by reducing the polymer to a small-sized pellet, transport costs back to the plastics factory can be significantly reduced.”
The Polysolve project was officially completed in November 2014.