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|REVISION CARDS - POLYURETHANE AND FOAM RUBBER|
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DISCOVERY OF POLYURETHANE
In1937, Otto Bayer mixed two chemicals, polyol (an alcohol) and isocyanate (sometimes called isonitrile or carbylamine).
The two chemicals formed a solid plastic. The resulting plastic was polyurethane (PUR), a new plastic.
PROPERTIES OF POLYURETHANE: Can be either thermoplastics or thermosetting. Can be cast and injection moulded. Long lasting. Performs well in high temperatures, but can be damaged / attacked by most solvents. Has low heat transfer / conductivity, consequently a good insulator. Has high resistance to abrasion. It can be manufactured in a range of colours.
When mixing two chemicals, polyol (an alcohol) and isocyanate (sometimes called isonitrile or carbylamine) with the addition of a small amount of water, the solution ‘fizzes’, forming foam rubber.
PROPERTIES OF FOAM RUBBER: Lightweight and flexible. Ideal of cushions or as a dense rigid material ideal for the trays. Resists impacts and is often used as protective packaging inserts. An excellent acoustic insulator, as it absorbs sound. Resists high temperatures (200oC) and consequently can be used to reduce sound from car engines. Performs well in high temperatures. Can be damaged / attacked by most solvents. It has low heat transfer / conductivity, consequently a good insulator.
FOAM RUBBER PRODUCTS
|1. Name the two materials discovered / invented in 1937 by Otto Bayer? 2 marks|
|2.List three products manufactured from Polyurethane and three manufactured from Foam Rubber. 6 marks|
|3. Describe three physical properties possessed by Foam Rubber. 3 marks|
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