Page 57 - Plastics News May 2019

TECHNOLOGY

Novel 'upcycling' process to give plastic second life

cientists have developed upcycling technologies that make single-use waste plastic
Sa recycling process that valuable to reclaim. This, in turn, could help keep waste
transforms single-use plastic SODVWLF RXW RI WKH ZRUOG V RFHDQV DQG RXW RI ODQGÀOOV
bottles, and fabrics made he said. However, there is still work to be done before
from a common polyester this recycling process can be implemented beyond the
material into more valuable laboratory bench. The team plans to further analyse the
products with a longer properties of the composite materials that result when
lifespan. A research published PET is combined with the plant-based monomers and to
in the journal Joule could test the process for scalability to determine how well it
help protect oceans from might fare in a manufacturing setting. They also hope
plastic waste by boosting the WR GHYHORS FRPSRVLWHV WKDW FDQ WKHPVHOYHV EH UHF\FOHG
recycled plastics market. Polyethylene terephthalate the current composites can last years and even decades
(PET) is strong but lightweight, resistant to water, and but are not necessarily recyclable in the end. In addition,
shatterproof -- properties that make it extremely popular the NREL team plans to develop similar technologies for
among manufacturers. Although PET is recyclable, most recycling other types of materials. "The scale of PET
of the 26 million tonnes produced every year ends up in production dwarfs that of composites manufacturing, so
ODQGÀOOV RU HOVHZKHUH LQ WKH HQYLURQPHQW ZKHUH LW WDNHV we need many more upcycling solutions to truly make a
hundreds of years to biodegrade. However, even when it global impact on plastics reclamation through technologies
is recycled, the process is far from perfect. Reclaimed like the one proposed in the current study," said Nicholas
PET has a lower value than the original and can only Rorrer, an engineer at NREL.
be repurposed once or twice. "Standard PET recycling
today is essentially 'downcycling'," said Gregg Beckham, 1HZ SRO\PHU ¿OPV FRQGXFW KHDW
a Senior Research Fellow at US Department of Energy's instead of trapping it
National Renewable Energy Laboratory (NREL). "The
process we came up with is a way to 'upcycle' PET into IT engineers have flipped the picture of the
long-lifetime, high-value composite materials like those Mstandard polymer insulator, by fabricating thin
that would be used in car parts, wind turbine blades, SRO\PHU ÀOPV WKDW FRQGXFW KHDW DQ DELOLW\ QRUPDOO\
surfboards, or snowboards," said Beckham. The team associated with metals. In experiments, they found
combined reclaimed PET with building blocks derived WKH ÀOPV ZKLFK DUH WKLQQHU WKDQ SODVWLF ZUDS FRQGXFW
from renewable sources such as waste plant biomass. This heat better than many metals, including steel and
resulted in a new material that combines reclaimed PET ceramic. The team's results, published in the journal
and sustainably sourced, bio-based molecules to produce Nature Communications, may spur the development
WZR W\SHV RI ÀEUH UHLQIRUFHG SODVWLFV )53V ZKLFK DUH RI SRO\PHU LQVXODWRUV DV OLJKWZHLJKW ÁH[LEOH DQG
2-3 times more valuable than the original PET, meaning corrosion-resistant alternatives to traditional metal
that future plastic bottles could live lucrative second heat conductors, for applications ranging from heat
lives. Through their collaboration with analysts at NREL, dissipating materials in laptops and cellphones,
to cooling elements in cars and refrigerators. The
the team also predicts that the composite product would researchers not only had to come up with a way to
require 57 per cent less energy to produce than reclaimed fabricate heat-conducting sheets of polymer, but
PET using the current recycling process and would emit 40 they also had to custom-build an apparatus to test
per cent fewer greenhouse gases than standard petroleum- the material's heat conduction, as well as develop
EDVHG )53V D VLJQLÀFDQW LPSURYHPHQW RYHU EXVLQHVV DV computer codes to analyze images of the material's
usual. "The idea is to develop technologies that would microscopic structures. the team was able to fabricate
incentivise the economics of PET reclamation," said thin films of conducting polymer, starting with a
Beckham. "That's the real hope -- to develop 'second-life' commercial polyethylene powder.

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