If you could somehow wave a magic wand and instantly remove every plastic-based
product from the world most people at least in the industrialized nations had probably be dead within
about a month or so. Plastics have become an essential component in just about every aspect of
modern life and they'll continue to be essential for the foreseeable future. Now you could argue
that the ubiquity of plastics is purely a product of brilliantly aggressive marketing
by the industry's PR people, but let's face it they were pushing an open door weren't they?
Plastic bottles are lighter and safer than glass and therefore cheaper and less environmentally
impactful to transport. Plastic bags are light and durable and easy to store. Household plumbing and
electrical systems are infinitely safer and more reliable as a direct result of plastic materials.
The manufacture of computers tablets and smartphones which have enabled the information
technology age we now live in would probably never have happened without the various types of plastic
that make up the majority of their structural elements. Plastics have also led to huge advances
in medical research and equipment saving countless lives over the last few decades, and they've
enabled the transport industry to reduce weight in road vehicles and aviation so that each journey
consumes far less fuel and therefore emits far fewer greenhouse gas emissions. I could go on but
you get the idea. In fact plastics are almost too good which, as we've all now come to realize, is
why we've got such a massive problem with plastic waste not only in our landfills but increasingly
in our waterways and oceans. The infamous pacific garbage patch is now the size of France
and contains about 80,000 tons of waste plastic, mostly in the form of discarded fishing gear.
That waste is gradually breaking down into microplastics that get into the food chain and
eventually into human beings, as this Queensland study is currently attempting to quantify
and clarify. According to Plastics Europe, in 2020 the world produced 367 million tons of
brand new virgin plastic and it's reckoned that since it first burst into our lives in the 1950s
just over 8 billion tons have been churned out, about half of which is still kicking around in
one form or another. That's a greater weight of plastic than all living biomass on the planet.
And plastic manufacturing releases greenhouse gas emissions that contribute to global warming. A
2021 report published by the Beyond Plastics team at Bennington College in Vermont found that the
U.S plastics industry alone produces 232 million tons of carbon dioxide equivalent emissions.
That's about the same as 116 coal-fired power plants. Most plastic recycling methods
are expensive and frankly inadequate, generally degrading the material more and more on each cycle
so that it eventually ends up as something unrecyclable like a cheap carpet after which
it's inevitably destined for the dreaded landfill, which means more and more harmful waste at one end
while ever more brand new plastics are being churned out at the other. But now a new process
has been developed that can rapidly deconstruct one of the most prevalent types of plastic at room
temperature keeping energy requirements and costs to a minimum. The resulting constituent materials
can then be up-cycled into value added products rather than down cycled into lower grade items,
and the process can be repeated indefinitely without any degradation. So have we finally
found a way to keep plastics revolving around a circular economy and out of the waste stream?
Hello and welcome to Just Have a Think. There's no doubt that plastics have brought unparalleled
prosperity in virtually every facet of society from health care and transport to agriculture
and communications. But on top of all the issues I mentioned a moment ago it's worth remembering
that . of current production comes from an unsustainable and rapidly depleting
fossil reserves. And we've only recently started to realize how our short-sighted
product design approaches have inadvertently caused such a wide scale environmental problem.
Now of course there's lots of work going on to develop more sustainable alternatives
that are biodegradable or compostable. I've looked at products like PLA and PEF in a previous video
and they do look like they could reduce the leakage of harmful chemicals into our soils and
water systems. I also looked at nature's solution to the plastic bombardment which is to evolve
bacteria that can break down the polymer chains and use the carbon content as their fuel source.
We'll come back to that one in a moment. But while these developments are an important step forward
they don't address the linear nature of material production and disposal particularly in things
like single-use plastics and packaging. In other words we'll still be churning out
millions of tons of the stuff and relying on the fact that we can more easily dispose of it
at the end of its life. What we really need are processes that allow us to keep the product in
circulation almost indefinitely. That'll cut down on the energy and resources we need to produce
new material from scratch and it'll reduce the pressure on the world's waste disposal system,
which is another very energy hungry industry. Unlike most existing mechanical recycling methods
which lead to all those cheap landfill carpets I mentioned earlier, chemical recycling can
theoretically preserve the quality and integrity of a plastic over an infinite number of cycles
and the number of different monomers and derived chemicals that can be gleaned from the polymer
structure of a plastic means lots of lucrative revenue streams for industry, which you'd think
would make chemical recycling an attractive option for market-driven corporations wouldn't you? The
trouble is though, the capital expenditure to set these systems up and the ongoing cost of
operating them has proven to be a bit of a deal breaker for many companies, who let's face it
still remain slaves to ever increasing quarterly revenues and profits for their rapacious
shareholders. So anyone who can come up with a way of chemically liberating the constituent
elements of existing plastics in a less expensive less energy-hungry and more sustainable way
is probably onto a winner. And this new research from the Centre for Sustainable and Circular
Technologies at the University of Bath here in the UK looks like it might just fit the bill.
The process uses a zinc based catalyst and methanol to completely break down beads of
a commercial polycarbonate known as Polybisphenol A Carbonate, or PBAC.
And it does it within 20 minutes, and crucially it achieves a transformation at room temperature.
Several different formations of zinc were created using ligands, which are molecules
or ions that combine to a central metal atom to form what's known as a coordination complex.
The much much more specific scientific explanation of the entire process is contained in this paper
published in February 2022 in the Chem Sus Chem journal at the Chemistry Europe website.
The intricate details are well outside the scope of this video but for those of you intrepid enough
to wade through the typically impenetrable scientific vocabulary I'll leave a link to
the paper in the description section below. The result of all that jolly clever sciency stuff
though is that the Polybisphenol A Carbonate is converted into its chemical constituents Bisphenol
A and Dimethyl Carbonate. Essentially they're the building blocks of the polymer which means there's
no material degradation during the process and it can be performed an unlimited number of times.
Bisphenol A is known to be a potentially damaging environmental pollutant
so using this process to create new products and keeping it out of our landfills and watercourses
will be greatly beneficial to the earth's ecosystems. Dimethyl Carbonate is also a useful
product that can be kept in this circular chain, it's a valuable green solvent and a building block
for other industrial chemicals. Not content with breaking down this polycarbonate though, the team
tried their new concoction on other polymers like polyethylene terephthalate or PET, which is what
drinks bottles are made of, and polylactic acid or PLA, which is a renewable plastic made from things
like sugar cane, starch and corn. And they found that with the addition of a little bit of heat
the zinc catalyst did a good job of breaking down those polymers as well. The monomers derived from
the PET breakdown were reconstructed to produce renewable polyester amides or PEAs
which have excellent thermal properties making them great candidates for biomedical applications
like drug delivery and tissue engineering. Those are just a couple of examples of what the team
has already achieved but there are likely to be many more materials and applications that
can be derived from this process as it gets ramped up to commercial industrial scale.
In this article by Vicky Just from Bath University the paper's lead author Jack Payne explains
"whilst plastics will play a key role in achieving a low carbon future,
current practices are unsustainable moving forward". He says "it's imperative we
source plastics from renewable feedstocks, embed biodegradability and recyclability at the design
phase and diversify existing waste management strategies. Such future innovation should not
be limited to emerging materials but should encompass the established products too."
They're not the only ones trying to crack the plastic up-cycling challenge though.
You may remember back in March 2020 I made a video looking at the amazing way
bacteria in landfills have evolved so they can break down the complex polymer chains of modern
plastics and use the carbon content as their fuel source. It's a very fortunate bit of support
that nature has kindly provided for us rather profligate humans and laboratory researchers
have been trying to enhance and turbocharge the process into something that can be applied
on a large enough scale to make a positive difference to our plastic pollution problem.
At the forefront of that research is a multinational consortium called Mix Up
which is an abbreviation of the rather cumbersome title Mixed Plastics Biodegradation and Upcycling
using Microbial Communities. I don't know about you but i particularly like the idea
of a community of microbes. Anyway they're all about creating a truly circular economy
for all types of plastic. Their objective is very clearly stated as "plastic waste to plastic value
by a sustainable biotechnological conversion of unsorted mixed plastics into valuable bioplastic
using heavily engineered enzyme mixtures and mixed microbial communities".
The project has 14 international partners from Europe and China
all working towards commercially viable production of upcycled bioplastics by the end of this decade.
Whether it's a newly created catalyst like the zinc ligand coordination complex at
Bath University or the amazing engineered superbugs currently being reprogrammed to
chomp through all types of polymer structures, the key to mitigating environmental catastrophes
from waste plastic pollution and dramatically reducing greenhouse gas emissions from the
production of virgin plastics is to ensure existing plastics are genuinely up-cycled
into value-added products using processes that can be repeated more or less indefinitely.
It's still relatively early days, and no doubt there'll be lots of pitfalls and barriers along
the way to full commercialization of these upcycling processes, but we do at least appear
now to have an industry that understands the size of the environmental emergency
and which is rapidly developing several potentially effective solutions to the problem.
Now if you're working in this field and you've got some insights you can share or if you just have
a view on how we should be dealing with plastics in general then why not dive down to the comment
section below and leave your thoughts there. That's it for this week though. Thanks as always
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