The University of New South Wales researchers have developed a new low-energy technique to recycle plastic, which promises the chance of greater recycling.
The process can transform many forms of waste plastic into their respective polymer nanoparticles dispersed in water.
UNSW state this can then either be extracted for re-use in preparing new consumer products, or utilised still in the aqueous dispersion in applications such as asphalting and waterproof coatings.
The innovative technique also removes dyes from the original plastic waste, which currently requires separate treatment, thus reducing the time and cost of recycling and expanding the waste source.
Team leads professor Per Zetterlund and Dr Vipul Agarwal, from the school of chemical engineering, are working in collaboration with FP Paradigm to further develop and commercialise the technology specifically pertaining to PET (polyethylene terephthalate) recycling.
“Plastics recycling is a massive challenge globally and there are many hurdles to overcome. For example, CSIRO statistics show that 84 per cent of plastic currently used in Australia is sent to landfill and only 13 per cent is recycled,” said Dr Agarwal.
The relevant aspects of the UNSW patent (PET in food and beverage applications) have been licenced to FP Paradigm.
“One of the main issues with the current way of recycling plastics is that it typically requires very high temperatures and therefore considerable amounts of energy and, in many cases, high shear forces during melt extrusion,” said Zetterlund.
Paco Industries, the research and development subcontractor for FP Paradigm, have recently announced a deal with the Arnott’s Group, to explore the use of this new technology as a more sustainable PET alternative across their range of products.
The UNSW researchers say their new method , which can be used on a wide range of common materials such as bags, bottles made from polyethylene, polypropylene, polystyrene, and PET, has the potential to significantly reduce the degradation of the plastic (polymers) during recycling.
“Our method has the potential of causing no mechanical or chemical degradation of the polymer, so we believe it may be possible to recycle the plastic a higher number of times than using existing recycling processes,” said Zetterlund.
This research is set to make the recycling process faster and more efficient, Zetterlund said, “There is no need for extensive cleaning of the waste plastic before it is recycled. This process also has the potential to separate the polymer from various additives such as dyes, eliminating one of the stages currently required in current recycling processes.”
UNSW explained Arnott’s are particularly keen on the fact that the process can isolate PET from other types of waste plastics and has the potential to turn contaminated PET waste back into food-grade PET for the food and beverage industry.
Arnott’s Group chief transformation officer Simon Lowden said, “This agreement reflects our commitment as a business to go beyond our sustainable commitments and find new technologies.”
PET is one of the world’s most commonly used plastics with approximately 10 per cent of all plastics being made from PET, with around a third of that used in global food and beverage packaging.
The primary challenge is the level of contamination in such plastic, making it harder to recycle without being thoroughly cleaned.