Researchers from the Polymer Processing Research Centre (PPRC) at Queen’s University Belfast have discovered new ways to convert single-use plastic waste into products such as storage tanks and sporting goods.
The PPRC researchers are pioneering a manufacturing process called rotational moulding. This has the potential to recycle large volumes of plastic waste into a wide variety of products such as urban street furniture, storage tanks for water and fuel, and marine buoys.
The project is funded by Innovate UK through its “Plastics Innovation: Towards Zero Waste” Programme.
The researchers are working in collaboration with three industrial partners; Impact Laboratories Ltd in Scotland, Impact Recycling Ltd in England and Harlequin Plastics Ltd in Northern Ireland.
Dr Peter Martin, from the School of Mechanical and Aerospace Engineering at Queen’s, explained: “The process starts with flakes of waste plastics being separated and compounded into pellets using the patented technologies of Impact Laboratories and Impact Recycling.
“At Queen’s we take these pellets and grind them into a fine powder, which is then blended with a proportion of new plastic (polyethylene), heated to over 200ºC and then cooled within a mould to transform it into the shape of a new product. Our research involves testing to find the optimum combination of blending the plastics and processing conditions so that eventually Harlequin Manufacturing will be able to introduce a range of new rotomoulded products made largely from post-consumer waste.
“It is expected that in one product of this kind waste plastic could replace around 30% of the new plastic required and use the equivalent of 1,000 old milk bottles in its manufacture.”
At present, the UK rotational moulding industry alone consumes more than 38,000 tonnes of new plastic, of which more than 11,000 tonnes could be saved.
Mark Kearns, Moulding Research Manager at PPRC at Queen’s, added: “This new process will have significant environmental benefits. The ability to condense and transform large volumes of recycled plastics into products designed to last many years will result in a substantial reduction in the amount of post-consumer waste going to landfill, rivers and the ocean.
“It will also help to reduce the quantity of pure polyethylene used in the process, ushering in a new and more sustainable era in the production of rotationally moulded plastics.”
Rotocycle is a £500,000 project funded by Innovate UK, which began in January 2019 and will last for two years.
Today the world produces over 300 million tonnes of plastics every year, which is almost equivalent to the weight of the entire human population. Much of this is single-use and not designed to be recycled, which creates a mountain of waste that enters the natural environment such as plastic pollution in the oceans.
