PhD in Polymer Engineering Kim
Ragaert, professor on materials science and polymer processing at the
University of Ghent (Belgium), offered in this city on April 25 an interesting TEDx talk entitled ‘Plastics Rehab’, which
we strongly recommend.
Indeed, we must get “rehab plastics” so that it does not continue
to make a “blind war against them for being the most visible abandoned
material.” With this last phrase Ragaert ends his reflections, which began
with this one: “Why does no one
blame metals, that they do not degrade in the environment?”.
2 grams of plastic film wraping a cucumber allows to extend its
conservation from 11 to 26 days with the consequent prevention of food waste
and CO2 derived emissions: if that “plastic skin” is not
used, CO2 emissions would be multiplied by five.
Plastics are extremely light materials. They have half the density of glass and a density similar to paper but
being very resistant they can be manufactured with minimum thickness compared
to other materials. This means that in their manufacture, they consume much
less resources and that they are much more efficient in their transportation.
Thus, to pack the same amount of liquid you need 24 times more glass than
plastic and twice as much fuel is consumed if it is transported. And it is true
that it is possible to reuse a glass bottle up to 8 times, but even just
recycling 50% of plastic bottles, is still using 6 times more material in the
case of glass than plastic. Additionally, the melting temperature of the glass
is about 1,500 ℃ when the plastic temperature is around 300 ℃, so the
energy to make a glass bottle is much higher than that needed to make a plastic
bottle. In conclusion, the plastic manufacturing and recycling system is,
on the whole, infinitely more efficient than glass.
“If we focus on banning plastics the environmental effects will be devastating”
On the other hand, if we compare a plastic bag with a paper bag, in order
to transport the same weight, it is necessary to use 20 grams of virgin plastic
versus 50 grams of recycled paper. Since paper requires much more energy,
water, land and trees for its manufacture and recycling, it would be necessary
to reuse the paper bag 4 times to compensate for the environmental impact
generated in its production, which is practically impossible due to its
fragility and breakage. And in the case that the bag was made of cotton, the
compensation of the environmental impact generated in its manufacture would not
be achieved until it was used 173 times due to the intensive use in water and
soil that is made in the cultivation of cotton. That’s why the best option is the reusable plastic bag that with 20
uses allows to generate positive environmental benefits.
If someone leaves a car in the middle of the street, do we blame the car?
Do we ban cars? The fault lies with whoever leave the car and the fine for
those who leave it. Studies show that
80% of abandoned waste, what we know as “littering”, come from
ourselves, from consumers.
If we focus on banning plastics the environmental effects will be
devastating because to produce products that meet the same functionalities the
amount of material, energy consumed and CO2 emitted will double or
even threefold. That is, we will be substituting
plastic for less sustainable alternatives and there will be a paradox that the
impact on the environment will be much greater. Just the opposite effect
that was looked for.
Consumers have the power to avoid this through the purchase of recyclable products which contain recycled
material and providing these products with an appropriate end of use by
depositing them in the selective collection containers.
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