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We see many news stories about
developments in the plastics industry to make these items greener.
With disposable plastic shopping bags being banned in some places
and consumer concern acting as the writing on the wall for the
industry, it's certainly in the sector's interest to make more
environmentally friendly plastic bag and wrap products as soon as
possible.
Degradable, compostable and biodegradable plastics may seem like
recent inventions, but some have been around for a very long time.
One such plastic is cellophane - and it's now experiencing
resurgence in popularity.
Cellophane being plant based didn't click with me until I was doing
some research recently for a restaurant employee who was looking for
a biodegradable bag suitable for use with a particular food
application - it was only then that it clicked with me the
"cello" in cellophane stands for cellulose - the
structural component of plants.
Cellophane was invented in 1900, but wasn't commercially available
until 1912. At that point it was mainly used for wrapping candy.
When moisture-proof cellophane hit the market in the late 1920's, it
rapidly increased in popularity until the 60's when alternative
petro-chemical based plastics became popular - and we all know how
that worked out for the planet.
Quite a few modern bioplastics use plants, but often they use corn
as the primary component. Similar to using "food as fuel";
should we be using a grain or a crop grown on land suitable for
producing food for non-food uses when arable land (without further
deforestation) is becoming a diminishing resource?
Cellophane has an edge here as it can be made from farmed trees or
from hemp; which can grow in relatively harsh conditions.
Regarding its composting and biodegradable attributes, I've read
various reports stating uncoated cellulose film degrades within 10
days to 1 month when buried and nitrocellulose-coated cellulose in 2
months to 3 months. Complete biodegradation of cellulose film is
between 1 - 2 months for uncoated products, and from 2.5 to 4 months
for coated cellulose products. In a fresh water environment, the
rate of biodegradation is only 10 days for uncoated film and a month
for coated cellulose film.
As far as I know, corn based bioplastics take far longer to degrade
and there's also some issues with recycling bioplastics made with
corn as they are currently classified as a number 7 plastic resin,
meaning "other".
That's the good news about cellophane; but as with most things,
there are some negative aspects too environmentally speaking.
Cellophane is made by dissolving plant fiber in alkali and carbon
disulfide to create something called viscose. The viscose is then
reconverted to cellulose in cellophane form after a sulfuric acid
and sodium sulfate bath. The cellophane is further treated
with glycerol to make the dry cellophane less brittle. The
cellophane may then be coated with nitrocellulose or wax to make it
impermeable to water vapor. A few nasty chemicals in that process -
for example, high levels of carbon disulfide are toxic; affecting
the nervous system.
However, given the amount of processing and nasties it takes to turn
petro-chemicals; i.e. chemicals derived from crude oil, into
plastics and the damage those plastics do long after having been
discarded, it would seem to me that cellophane is probably still
better environmentally speaking. Stacked up against corn based
plastic bags and wraps, the better/worse distinction is a little
harder to discern.
Cellophane films and bags are readily available - just run a query
on the terms in your favorite search engine to locate a stockist.
Tip: When composting cellophane, scrunch it up instead of laying it
flat on your compost pile. This allows for air pockets and some air
is necessary when composting any material.
Trivia: another plastic product that's been around for at
least a hundred years also based on plant material is linoleum.
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