ECO-FRIENDLY PLASTIC
By Anton Antonio
September 8, 2015
Have you ever
heard of the “Great Pacific Garbage Patch”?
“The Great Pacific Garbage Patch”, also described as the Pacific Trash
Vortex, is a gyre of Marine debris particles in the central North Pacific
Ocean. The patch extends over an
indeterminate area, with estimates ranging very widely depending on the degree
of plastic concentration used to define the affected area. The patch is characterized by exceptionally
high concentrations of pelagic plastics, chemical sludge and other debris that
have been trapped by the currents of the North Pacific Gyre.” (Antonio, 2014)
The biggest
volume of materials in the Great Pacific Garbage Patch is plastics. It seems quite impossible to ban the
manufacture of plastics but there has to be a way to produce biodegradable and
environment-friendly plastic. Here is a
researched material on this possibility…
“The fate of the
world’s oceans may rest inside a stainless steel tank not quite the size of a
small beer keg. Inside, genetically
modified bacteria turn corn syrup into a churning mass of polymers that can be
used to produce a wide variety of common plastics. “It’s a bit like making yogurt,” says Oliver
Peoples, chief scientific officer of Metabolix, Inc.
The Cambridge, Massachusetts-based company where bioplastics
take shape in laboratory-scale fermentation chambers is one of a growing number
of businesses and institutions working to develop cost-competitive, more
environmentally friendly replacements for conventional plastics, which are made
from fossil fuels, fail to decompose and are turning our oceans into seas of
floating plastic. “We’ve seen this huge
increase in production in plastic that results in an increase in the waste
stream as well,” says Jenna Jambeck, an environmental engineering faculty
member at the University of Georgia.
“Unlike material that biodegrades, plastic has all of these issues. It easily travels into waterways, it
physically fragments into smaller pieces which are extremely hard or impossible
to collect, and (it tends to) absorb chemical contaminants that are already in
the environment.”
Some 4.8 million to 12.7 million metric tons (5.3 million to
14 million tons) of plastic, or up to 4% of the roughly 300 million metric tons
(330 million tons) of plastic produced each year, entered the ocean as trash in
2010. The figure is expected to increase
10-fold in the next decade as more plastic is produced and subsequently evades
waste management and recycling efforts, according to a study Jambeck and
colleagues published earlier this year in the journal Science.
What effect all this plastic has on living things, including
humans, remains unclear. A number of
recent studies show that chemicals in small bits of plastic, and even the
plastic bits themselves, can accumulate in birds, fish and other marine
life. Laboratory testing has shown the
chemicals that comprise them can cause adverse health effects, including liver
damage and endocrine disruption through altered gene expression. Whether similar effects occur outside the
laboratory or whether they extend up the food chain to people who eat marine
organisms remains unknown, yet both seem entirely plausible. And that’s not
all. Plastics are notorious in the
greenhouse gas department as well.
Roughly 8% of the petroleum used worldwide each year goes to make
plastic directly or to power the plastic manufacturing processes, according to
a recent report by the Worldwatch Institute.
Why not just reduce
our use? For one thing, plastics are
incredibly versatile, meeting a spectrum of needs for flexibility, cost and
other parameters that substitute materials present their own adverse
environmental, social and health impacts.
“Even though people feel like they would like to use less plastic rather
than more, the fact of the matter is that plastics are modern materials that
make cars lighter, purify water and add tremendous benefit to health and
security applications,” say Marc Hillmyer, director of the Center for
Sustainable Polymers at the University of Minnesota in Minneapolis.
On other words, there are solid reasons for pursuing more
sustainable alternatives to conventional plastics – namely, plant-based
plastics. Such so-called bioplastics are
able to degrade, dramatically reducing the risk that they’ll end up polluting
land and sea. They also lower our
dependence on fossil fuels, reducing plastic’s carbon footprint. Greenhouse gas emissions associated with
bioplastics are 26% lower than those associated with conventional plastic,
according to a recent life cycle analysis of corn-based and petroleum-based
plastic by researchers at Michigan State University.
Finding non-petroleum-based, decomposable alternatives to
today’s plastics, however, isn’t easy.
Plastic made from corn, sugarcane or other plant-based material isn’t
necessarily degradable, and getting degradation to occur when you want it to
can be difficult. “You don’t want your
plastic bag to degrade while you are using it,” Hillmyer says. “On the other hand you want it to degrade
rapidly when out into another environment.”
While chemists have had difficulty reformulating petroleum-based
plastics so that they can degrade, a number of bio-based, degradable
alternatives are emerging.
Natureworks, a company based in Minnetonka, Minnesota, is
one of the world’s leading manufacturers of bioplastics. The company makes polyactic acid, or PLA, a
biodegradable plastic it sources from cornstarch and makes into a wide range of
consumer products – including single-use flatware, cups and packaging – that
decompose at the end of their useful life.
The company’s initial production facility in Blair, Nebraska, came
online in 2002 and can produce 140,000 metric tons (150,000 tons) of PLA per
year. The company recently announced
plans to open a second plant in Southeast Asia that would use sugarcane as its
feedstock.
Another leading manufacturer of bioplastics in the Coca-Cola
Company, which in 2009 launched PlantBottle, a drink bottle made from
polyethylene – PET – that contains up to 30% bio-based plastics, can be
recycled along with conventional PET, a commonly recycled plastic. Since 2009 the company has produced 35
billion of its original PlantBottles. In
June 2005 the company unveiled a new version that is 100 percent biobased.
Despite these and other recent successes, bioplastics remain
a tiny fraction of the industry as a whole.
The materials are well suited for single use products such as spoons and
bottles where consumers are willing to pay a premium for more sustainable products. High durability, less-visible applications –
for example, water pipes made of PVC that are commonly used in residential and
commercial plumbing – are still made entirely of conventional plastic. In total, less than 0.5% of all plastic comes
from non-petroleum sources, according to the Society of the Plastics Industry,
an industry trade group based in Washington, D.C.
Government regulation, however, is leading to the increased
use of bioplastics. In 2014 Illinois
banned microbeads, tiny plastic abrasives commonly used in facial scrubs,
shampoo and toothpaste, due to concerns about environmental degradation in the
Great Lakes. At less than one millimetre
in diameter, microbeads are too small to filtered by sewage treatment systems
and have been found in both freshwater and marine environments.
With a federal ban on microbeads expected, Metabolix
partnered with Honeywell in March to produce a biodegradable alternative to
microbeads. The microbeads the two
companies are developing are made from Polyhydroxyalkanoates, or PHA, a
bio-based plastic that is more expensive but also more versatile than PLA. The microbeads the two companies are
developing are made by fermenting cornstarch, though they could also be made
from non-food crops such as switchgrass.
PHA microbeads will degrade into carbon dioxide and water in a matter of
months at the same rate as cellulose or paper, Peoples says.
As we increase our reliance on plastics sourced from crops
such as corn and sugarcane, we could inadvertently introduce new environmental
concerns. A recent study in the journal
Cleaner Production noted bioplastics grown from agricultural feedstocks use
significant amounts of water, pesticides and fertilizers that can cause air and
water pollution and compete for land with crops grown for food. One possible way to get around the down sides
of plant-based plastics while still reducing dependence on petroleum is to use
CO2 as feedstock instead. Novomer, a
company spun out from research at Cornell University in Ithaca, New York, is
turning waste CO2 from ethanol production plants into plastic. The company makes polyols – polymers used to
make flexible foam found in mattresses, seat cushions and insulation, as well
as a range of specialty coatings and sealants.
“If your mattress was made with our material, it would be roughly 22% by
weight carbon dioxide,” says Peter Shepard, Novomer’s executive vice president
of polymers. “It takes a greenhouse gas that
is a waste material and turns it into valuable product.” Typically CO2 is too inert to react with
other compounds, making its use in plastics or other applications
difficult. Geoffrey Coates, a chemistry
professor at Cornell University in Ithaca and a co-founder of Novomer,
developed a catalyst that increased the reactivity of CO2 while simultaneously
slowing down the reactivity of another key polyol ingredient – making it easier
to incorporate CO2 into the resulting polymer.
“It’s like if you have kids and you give them pizza and broccoli and you
tell them every time you take a bite of pizza you have to take a bite of
broccoli,” says Coates, who is also a member of the Center of Sustainable
Polymers. The polyols made by Novomer
are degradable but lose their degradability when combines with petroleum-based
chemicals to make foam. Though the
company is currently focused on making foams and sealants, Shepard says
Novomer’s CO2-based polymers cold be used to make degradable plastics with CO2
content as high as 50%.
Despite strong growth in recent years, some say bioplastics
haven’t lived up to their potential.
“The bioplastics industry has not been able to create polymers that are
attractive enough in terms of pricing and in terms of properties that will make
the world willing to change,” says Frederick Scheer, the former CEO of
Cereplast, a once-leading bioplastics company that declared bankruptcy in
2014. The biggest challenge for
bioplastics is that they are competing against conventional plastics,
incredibly inexpensive materials that have been honed for the past 60 years,
Scheer says. “People are somewhat
conscious of the environmental impact of oil-based materials that will not
biodegrade, but they are not willing to spend the extra dollars to push (new)
types of materials,” he says.
Competition with petroleum-based plastic has only intensified over the
past year as the price of oil has dropped in half. “In order to be competitive with traditional
oil-based material we needed the price of oil to be somewhere around $130, $140
a barrel,” Scheer says. “Clearly, at $50
a barrel we are far away from being able to compete.” Scheer says the capacity to make all of the
world’s plastic from non-petroleum sources exists, but to do so would require
significant government support. “It will
have to be driven by regulation that will force the cost of plastic and cost of
oil to be substantially higher than it is right now,” he says.
If sustainable plastics that reduce our dependence on fossil
fuels and degrade at the end of their useful life are going to go mainstream,
they will have to be able to sub in not only for microbeads, foam and other
specialty applications but also for thermoplastics – low-cost, shapeable
polymers that comprise more than 80% of the hundreds of millions of tons of
plastic produced each year. Coates is
now working on a new biopolymer with properties comparable to or perhaps better
than polyethylene, the most widely produced thermoplastic used to make
everything from trash bags to water bottles to plastic toys. Even a thin layer of polyethylene is incredibly
strong, making, for example, mailing envelopes that are nearly impossible to
open without scissors or milk jugs that don’t break when dropped on the
floor. “Most of that is because it’s a
semicrystalline material,” Coates says.
“the (polymer) chains pack next to each other in a very tight and
specific fashion that overall, gives pretty impressive properties.” In a 2014 study published in the Journal of
the American Chemical Society, Coates and colleagues at Cornell described a new
material with a semicrystalline structure that is made from a sugar feedstock
and has properties similar to polyethylene, yet is better able to decompose at
the end of its useful life. “It doesn’t
happen overnight, but I think there are certain positive (indications that it)
could be a real competitor for a plastic like polyethylene,” Hillmyer
says. The new material, known as poly
(polypropylene succinate), hasn’t been tested to see how quickly it would
decompose in a landfill or marine environment.
But based on its composition, Coates says, it should begin to degrade in
water after several months, a time period that would exceed the useful life of
most single use products. Poly
(polypropylene succinate) breaks down into propylene glycol and succinic acid,
nontoxic materials that are further reduced to CO2 and water when ingested by
microbes. “If you had to eat polymer
degradation products, these would be the ones you want,” Coates says. It’s unlikely that poly (polypropylene
succinate) will ever coast less on a pound-for-pound basis than conventional
polyethylene, but its unique crystalline structure suggests it could perform
better than its petroleum counterpart.
If so, bioplastics manufacturers may someday be able to compete with
today’s plastics industry by making things like milk jugs with significantly
less material than petroleum-based plastics.
Short of sweeping government regulations that place a price
on carbon or require all plastics to biodegrade, bioplastics will have to find
ways to outcompete conventional plastics if they are ever going to fill more
than niche applications. It’s an uphill
battle – but one that another once-niche product, the solar panel, is
increasingly winning. In 2007 solar
power made up less than 0.1% of U.S. electricity generation. Thanks to ingenuity and innovation, the price
of photovoltaic modules has dropped from $4 per watt to $0.50 per watt, making
solar the fastest growing source of electricity in the country. Might those working on bioplastics see
similar sea change? Ultimately, a lot
will likely ride not only on how well their products break down, but on how
much they can break down conventional plastic’s competitive edge.” --- qc.com
The effort s being put into creating or producing
biodegradable plastics from plant-based inputs is truly commendable. We should, however, also be aware of the
pressure that this initiative will put on land use and food security. Hopefully, we need not make a choice between
food on the table and materials for eco-friendly plastic.
Thoughts to
promote positive action…
(Please
visit, like and share Pro EARTH Crusaders on Facebook or follow me at http://antonantonio.blogspot.com/
and http://twitter.com/EarthCrusader.)
REFERENCES:
Antonio, A. C., (2014). “The Great Pacific Garbage
Patch”. Retrieved on September 8, 2015
from http://antonantonio.blogspot.com/2014/08/the-great-pacific-garbage-patch.html
Qz.com, (2015). “Scientists have Found a Way to Make
Eco-Friendly Plastic Out of Corn Syrup and Bacteria”. Retrieved on September 8,
2015 from http://qz.com/469642/scientists-have-found-a-way-to-make-eco-friendly-plastic-out-of-corn-syrup-and-bacteria/
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