to ashes, dust to dust
Plastic littering the countryside
could soon be a thing of the past.
Researchers have come up with an additive that enables plastic
bags to be quickly decomposed by sun and rain.
DEGRADATION: An additive based on natural
ingredients helps to break down plastics faster than a
Materials and Chemistry.
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|Photo: Raymond Nilsson
Nor-X Industry AS, a company located in
Sunnmøre, has launched the additive that makes plastic decompose
in a short time when exposed to light and humidity. The additive also
makes the plastic considerably stronger, and it is cheap to produce.
This is all the result of a collaboration between the company and
SINTEF,which began in 1999.
The relationship started when Nor-X Industry’s parent company,
Nor- Mors AS, wanted to make chin-collars to enable dead people
to look nicer in their coffins. They wanted the collars to start
the decomposing process after the burial so they contacted SINTEF
to solve the problem. The research scientists were successful in
finding an additive on the market that had the desired effect. But
there was one problem: the collars became dark and extremely visible,
but the aim was for them to be as neutral as possible. This was
difficult to achieve with the additives available on the market.
The solution turned up together with a newly
appointed research scientist from France. He suggested an idea to
alter the additive so the end product would be lighter. This provided
the desired result and the colour of the end product was virtually
perfect. However, at that stage the manufacturing was so expensive
that it would not have been economically viable in a manufacturing
The research collaboration developed further through ‘SkatteFunn’
tax incentive scheme project. The objective now was an additive
for plastic that could be handled industrially and used in plastic
foil, plastic bags and food packaging. The product is a ferric organic
compound. If it is added during manufacturing, it will provide both
a rapid decomposition and a light colour. The results were so promising
that NorMors started the new company, Nor-X Industry, to handle
production and marketing.
THE TECHNOLOGY BEHIND IT
“Polyethylene and polypropylene,which we are talking about
here, are sensitive to ultraviolet light, so we are just talking
about assisting nature a bit,” says SINTEF senior research
scientist Ferdinand Männle.
In addition to light, a little humidity,
heat and oxygen are required, all of which are abundantly available
in nature. Nevertheless, an ordinary polyethylene bag would take
more than a year before it began to decompose, but the new plastic
bags will break down quicker than an apple on the ground. After
two weeks in sunlight, the bags will still have 90 percent of their
strength, but after five weeks only traces will remain. The decomposition
process occurs in several stages. Firstly, the light cuts the molecules
in the plastic down to such small pieces that they are ideal food
for micro organisms.
The satisfied micro organisms are in turn
eaten by others and play a part in the food chain. The end products,
which are common materials in nature, can be found in plants, moss
and perhaps in earthworms. The amount of rust that remains will
be so minute that it will be virtually impossible to measure. The
concentration of iron in the plastic is so low that in numerical
terms it would be some parts per million.
In addition to conventional shopping bags, plastic for silo bales
in agriculture is another actual use. As this plastic contains formic
acid, no one is willing to recycle it. The bales need to last at
least a year to satisfy users, and the alternative is to add a less
aggressive form of the additive in the plastic so that it only begins
to decompose after 18 months. Nor-X Industry has also reached an
agreement with the German Farmers’ Co-operative to produce
an agricultural film foil for the fields around Berlin.
The film will keep the soil warm in Spring
and protect against the fear of frosty nights when farmers have
planted potatoes. It will start to decompose after four to six weeks.
Research is currently underway on additives in several other contexts,
including for use in oil protection preparedness. The product has
shown that it has the capacity to materialise and break down oil.
Åse Dragland/Jan Helstad