Earth Materials

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E.g. The polymerisation of Ethane C2H4 :

Monomer

Ethene

Unsaturated hydrocarbon

Polymer

Poly(ethene)

Good for plastic bags & buckets etc

Slide 44

E.g. The polymerisation of Propene C3H6 :

Monomer

Propene

Unsaturated hydrocarbon

Polymer

Poly(propene)

Good for ropes etc

Slide 45

E.g. The polymerisation of Styrene :

Styrene Monomer

Poly(styrene)

Polymer

Packaging, foam cups etc.

Slide 46

E.g. The polymerisation of Vinyl Chloride :

Vinyl Chloride

Monomer

Poly(vinylchloride) PVC

Polymer

Window frames, waterproof clothing etc

Slide 47

E.g. The polymerisation of Tetrafluroethene :

Poly(tetrafluroethene) PTFE

(Non-stick coating - Teflon)

Polymer

Tetrafluroethene

Monomer

Slide 48

Some uses of Plastics

Slide 49

Problems with Plastics

The co-valent bonds holding the long molecules together are very strong. Few bacteria can make them rot down. They tend not to be Biodegradable.(What does this word mean?)

This makes disposing of plastics difficult:

Burning them produces oxides of Carbon, Hydrogen and sometimes Sulphur and other toxic compounds:

Carbon Dioxide, Sulphur Dioxide, Water vapour

They fill up land-fill sites.

(Why should these factors be a problem?)

Slide 50

Why not recycle plastics?

Recycling plastics is complicated by several issues:

·Not all plastics lend themselves to recycling

·Different types of plastic have different properties, and so separation is very important.

·The economics of recycling are not always favourable, as the market is prone to fluctuate. For example, when oil prices fall the production of ‘new’ plastics become cheaper, so providing its recycled counterpart with greater competition.

·Unlike some countries a lack of subsidy in the UK makes a recycling industry more difficult to sustain, so nationally our recycling performance tends to lag behind many of our European neighbours.

However, increasing pressures on landfill sites, and our need to conserve natural resources makes recycling of plastics an important step forwards.

Slide 51

Why not burn them then?