Slides in this set
Polymers are plastics made up of many monomer units.
They are usually strong, durable and can be of great use.
However, they require crude oil to be made; and crude
oil is running out. Polymers, once made, also cause a
problem of disposal. 85% of plastics are disposed of in
landfills which are getting too full.
Mechelle Bennett…read more
· Polystyrene [Poly(phenylethene)]
It is used for insulation, foam packaging , making models etc. This
polymer has relatively cheap costs, but it is in the process of being
replaced by biodegradable materials to promote sustainable
· Polythene [Poly(ethene)]
This polymer is commonly used in shopping bags, drinks bottles etc.
· Polypropylene [Poly(propene)]
It's uses are for dish-washer safe food packaging, equipment in the
laboratory as it has high resistance to chemicals, fibres in carpets etc.
The physical properties of addition polymers make them extremely
useful; they are durable and fairly un-reactive, however, they are not
biodegradable so their disposal causes a great dilemma.…read more
· Landfill sites
Space in landfill sites is running out, and 85% of plastics
are ending up here. Most of our waste ends up in other
countries and some of the plastics have poisonous
substances added to them like colorants and stabilisers.
http://bit.ly/gWVFXx http://bit.ly/fHpfyM http://bit.ly/fvG0au…read more
We can re-use plastics to save the earths resources.
This is the first stage of recycling. The plastics are separated into groups of
the same type of polymer identification codes. This used to be done by hand,
but technologies have been developed which use scanning sytems to
determine different types of plastics during the sorting process.
In this last stage, the polymers are first cut into small fakes and then washed
to remove impurities. These pellets are sent to manufacturing companies,
melted and re-moulded into new products.
These plastics are normally converted into:
PET= new bottles, carpets and clothing, food containers.
HDPE= plastic boxes, bins
LDPE= Plastic refuse sacks…read more
Feedstock recycling converts plastics into more useful products, rather than them
being thrown into landfills.
· Polymers can be converted into synthesis gas(this is a mixture of hydrogen and
carbon monoxide). These gasses are used as chemical feedstock. This chemical
feedstock is used for the conversion of plastics into more useful products or fuels.
· Scientists are developing this process in order to increase the percentage yield and
efficiency of it.
PVC [Poly(vinyl chloride)] - e.g. Wiring coatings
This process was developed as an alternative to disposing PVC in land fill sites.
PVC contains a high amount of Chlorine and combustion of it, during the recycling
process, releases toxic fumes which can cause corrosion in the plant and harm the
environment. This recycling is not economical as the resulting product is much less
cost effective than ones made from crude oil.
But PVC recycling plants, which use a different method, are now being created. They
separate PVC from other plastics by using solvents to dissolve them. Precipitation
then recovers Good quality PVC from this solvent. (Te solvent can also be recovered
and reused)…read more