Page 35 - Curriculum Visions Dynamic Book

 Rubber is used in a very wide range of products wherever elastic, waterproof properties are required. In this factory rubber is being used for making gloves for laboratory use. The formers, made of a ceramic material, are dipped into a bath of latex, giving them a coating. The coated formers are transported through an oven, where the rubber dries. The gloves are pulled off the formers and a drying powder is puffed into them to make them easier to pull on and off. Air is blown into each glove to test for defects. All the gloves used by the chemists in the demonstrations in this series of books were made on this Malaysian production line.
latex: (the Latin word for “liquid”)
a suspension of small polymer particles in water. The rubber that flows from
a rubber tree is a natural latex. Some synthetic polymers are made as latexes, allowing polymerisation to take place
in water.
polymerisation: a chemical reaction
in which large numbers of similar molecules arrange themselves into large molecules, usually long chains. This process usually happens when there is
a suitable catalyst present. For example, ethene reacts to form polythene in the presence of certain catalysts.
vulcanisation: forming cross-links between polymer chains to increase the strength of the whole polymer. Rubbers are vulcanised using sulphur when making tyres and other strong materials.
Also... The history of rubber
Rubber was first noticed by Europeans when Christopher Columbus arrived in the Americas. Natural rubber is
a suspension of about 30% rubber particles in water. It is a white latex sap that flows naturally from rubber trees if the bark is scored.
The first person to find a use for the material was Charles Macintosh who, in 1823, discovered that it could be used to make fabric waterproof. However, because natural rubber has no cross- links, it is difficult to use, becoming sticky when hot and stiff when cold. In 1839 Charles Goodyear invented the technique of vulcanising rubber by heating it with sulphur.
As early as 1826, Michael Faraday found that rubber was a polymer of the monomer isoprene. The first artificial
rubber was made during World War II, when there was a shortage of natural rubber. Styrene and butadiene are now used as the foundation of the modern synthetic rubber industry because they
are more easily obtained than isoprene. They are all derived from petroleum.
 Styrene, C6H5CHCH2 is a hydrocarbon monomer. It is stored as a liquid, but on exposure to air it polymerises, setting into the shape of the container.
In much polymer chemistry, the polymer is formulated so that it has useful properties when solid.
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