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C2 Material Choices (Modifications in Polymers (Increased chain length…
C2 Material Choices
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Materials
Synthetic materials are produced by chemical synthesis, and they are made from materials extracted from Earth's crust
Natural materials come from living things e.g. cotton and paper from plants and silk and wool from animals
Crude oil is a raw material found in the Earth's crust (a thick black liquid made from hydrocarbons), and is separated by fractional distillation into useful fractions. The hydrocarbons in a fraction have similar boiling points, and different fractions all have different boiling points
Crude oil is heated to evaporate all of the hydrocarbons. The vapour passes into the fractionating column and cools as it rises. Each fraction condenses to a liquid and runs off when it has cooled below its boiling point. The top of the column is 25 degrees C, and the bottom is 350 degrees C.
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All molecules have intermolecular forces. The longer the hydrocarbons molecules are, the stronger the IM forces, and stronger forces need more energy to overcome them. This is why a higher temperature is needed to boil the longer hydrocarbon fractions.
Nanotechnology
Nanotechnology is the production, study and control of tiny particles on a nanoscale (1 to 100 nanometres) that can be used to modify the properties of other materials, especially polymers.
Silver nanoparticles can give fibres in socks and other clothing antibacterial properties.
Carbon nanotubes in sports equipment e.g. Tennis rackets and golf clubs can make them lighter, stiffer and stronger.
Nanotechnology is a very new science, so some people are worried that the new materials haven't been thoroughly tested and could lead to health problems in the future. For example, if nanoparticles in the bloodstream enter the brain it could be very dangerous.
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Nanoscale materials
A nanometre is one millionth of a metre, the width of a few atoms. Nanoparticles can occur naturally (in sea spray) occur as an accidental result of human activity (particulate carbon) or be made deliberately by scientists (this is called nanotechnology)
Nanoparticles have different properties to larger particles because they have a much larger surface area.
Properties of materials
Different solids have different properties, e.g. different melting/boiling points, can be rigid or flexible, hard or soft, strong of weak (in tension and compression)
Plastic (polythene): lightweight, flexible, easily moulded, used for plastic bags and mounded containers
Plastic (polystyrene): lightweight, stiff, good thermal insulator as foam, water resistant, used for meat trays, coffee cups, protecting appliances and electronics
Vulcanised rubber: high tensile strength, hard and flexible, used for car tyres, conveyor belts and shock absorbers
Synthetic fibres (nylon): lightweight, tough and waterproof, blocks UV light, used for clothing and climbing ropes
Unvulcanised rubber: low tensile strength, sift and flexible, used for erasers and rubber bands
Synthetic fibres (polyester): lightweight, tough and waterproof, username for clothing and bottles
Polymers
In polymerisation, small hydrocarbon molecules (monomers) are joined together to very long molecules (polymers)
By choosing different monomers for polymerisation, you can produce a range of polymers with different properties that can then be use daily for different things