Polyurethane (AU),(PU),(PUR) Polyurethane is an organic material of high molecular weight whose chemical composition is characterised by a large number of urethane groups. Within certain temperature limits, polyurethane possesses the characteristic elastic properties of rubber. The composition of the material is determined by three components:
polyol
diisocyanate
chain extender
The type and amount of these materials used, and the reaction conditions, are decisive in determining the properties of the resulting polyurethane material.
Polyurethanes possess the following properties:
high mechanical strength
good abrasion resistance
modulus of elasticity which can be varied within wide limits
good flexibility
hardness variable over a wide range whilst retaining good elasticity, (polyurethane fills the gap between soft, elastic rubber types and brittle plastics)
very good resistance to ozone and oxygen
Good resistance to swelling in mineral oils
and greases, water, water-oil mixtures, and aliphatic hydrocarbons
Temperature range for use: -30°C/-22°F to +80°C/175°F, high performance types
(compounds) up to +100°C/212°F in mineral oils. Not resistant to polar solvents, chlorinated hydrocarbons, aromatics, brake fluids, acids and alkalis.
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