IN THE LABORATORY
57recyclinginternational.com | January/February | 2023
Activating
America’s urban
mine of PVC
waste
Polyvinyl chloride (PVC) is one of the most pro-
duced plastics in the US and the third highest by
volume in the world. However, producers and
scientists have been struggling to recycle the
material for decades. A new R&D project at the
University of Michigan brings hope.
PVC is pretty much all around us: in
window frames, flooring, pipes and
hospital equipment such as tubing and
blood bags. And yet, in the US the
material has a zero recycling rate. Now
researchers Danielle Fagnani and Anne
McNeil say they’ve found a way to
chemically treat PVC despite its tricky
plasticisers.
Their work at the University of
Michigan aims to break down as many
polymers as possible into their constit-
uent parts to produce non-degraded
materials that industry can incorporate
back into production.
In Europe, the PVC industry has recy-
cled 6.5 million tonnes of used PVC
since 2000. Industry body VinylPlus
reports the sector averages an annual
recycling rate of roughly 27% and has
thus prevented the release of nearly 13
million tonnes of CO2 into the atmo-
sphere.
NO HEAT, FEWER RISKS
Plastic is typically recycled by melting it
down and reforming it. However, when
heat is applied to PVC, toxic plasticis-
ers leach out of the material very easily.
‘This contaminates everything in the
recycling stream,’ the researchers say.
Another problem is that the hydrochlo-
ric acid contained in PVC can corrode
recycling equipment and burn skin and
eyes. On top of this, the phthalates are
highly toxic endocrine disruptors that
could interfere with thyroid and growth
hormones and those involved with
reproduction.
‘So we have to find a way to recycle
PVC that does not require heat,’
Fagnani argues. Her team turned to
electrochemistry, which introduces an
electron into the system causing a neg-
ative charge. This breaks the carbon-
chloride bond and yields a negatively
charged chloride ion.
REPURPOSING PVC WASTE
‘What we found is that this approach
still releases hydrochloric acid but at a
much slower, more controlled rate,’
she explains. The acid can later be
used by industries as a reagent for
other chemical reactions. Chloride ions
can also be used to chlorinate arenes,
small molecules which are frequently
used in pharmaceutical and agricultural
components.
Some material from the polymer
remains, for which McNeil says the
group is still looking for a use. Both
researchers are confident their innova-
tive method could inspire other strate-
gies for repurposing waste PVC and
related polymers using electro-synthet-
ic reactions.
‘Let’s be strategic with the additives
that are in plastics formulations,
‘Fagnani adds. ‘Let’s think about the
during-use and end-of-use from the
perspective of the additives.’ She
may be able to apply her work at her
new employer Ashland, a company
focused on making biodegradable
additives to consumer goods such as
laundry detergents and shampoos.
‘Current group members are trying to
improve the efficiency of this process
even more.’
For more information, contact Anne
McNeil via: [email protected]
Share your innovative projects with
us via:
[email protected]
A U T H O R Kirstin Linnenkoper
RESEARCH
PIONEER __
_________
SUPPORT FR
OM
Plastics recyc
ling
Danie
lle
Fagnani & An
ne McNeil
University of
Michigan
57_inthelab.indd 57 03-02-2023 14:11
