History

The production of semi-synthetic thermo-setting plastic materials arguably began with the production of vulcanised rubber in the USA and England in the 1840s. Independently, Alexander Parkes in England patented a plastic material based on cellulose nitrate in 1861, which indirectly led to the introduction of other semi-synthetic thermosetting plastics which were generally used in conjunction with an inert filler. The first modern thermoplastics were all developed in the late 1920s or 1930s such as PVC, polystyrene, polythene and nylon. The general structure of plastics was proposed by Hermann Staudinger in Germany in 1920 (he called polymers "macromolecules") but he was only awarded the Nobel Prize for Chemistry in 1953. Post-war work led to polycarbonate and polypropylene.

 
   
Physics and chemistry

Basically all plastics are polymers where many identical small molecules are reacted together to produce long chains of molecules, but the chains are not joined together very strongly so the polymer can usually be melted quite easily. The properties of the plastics are mostly affected by the type of molecule, the length of chain, the organisation of chains and the types of additives used to produce the product. For example plastic molecules of the chains aliening close together, can take some of the properties of a crystal. These polymers are much more likely to be transparent.

 
   
Applications

Polymers are used most often where economies of scale can be achieved to take advantages of the excellent moulding abilities. Drinks bottles made from PET are a good example. But also everything else from plastic bags to artificial blood vessels to (if you include resins) entire aeroplane wings when used with carbon fibre.

 
 
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