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Low density polyethylene:-it is manufactured by heating ethylene to 350-570k under pressure of 1000-2000 atmosphere and in presence of a trace of oxygen and peroxide.
- Low density polyethene is a transparent polymer of moderate tensile strength and high toughness.
- It is a poor conductor of electricity
- It is used as packaging material
- In production of wires and cables, squeeze bottles.
Production of high density polyethene:-in the process of preparation ethane is heated to 333-343 k under a pressure of 6-7 atmospheres in presence of a catalyst consisting of triethyl aluminium and titanium tricholoride and tetrachloride
Polyterafluoroethane:-it is manufactured by heating tetrafluroetene in presence of peroxide or ammonium per sulphate catalyst at high pressures.
Uses:-it is Flexible and inert to solvents and to boiling acids. Because of its great chemivalintertness and high thermal stability it is used for making non stickutensils.
Polyacrylonitrile:- starting material acrylonitrile (CH2=CH–CN)
Reaction:-Addition polymerisation of acrylonitrile in presence of peroxide catalyst gives poly acrylonitrile
It is a hardhorny and melting material.
- It is used as a substitute for wool in the manufacture of Orion and Acrilan fibres.
- It is also used in the preparation of other polymers.
Condensation Polymerisation or step growth polymerisation:- If the two bifunctionalmonomer molecules undergo condensation with loss of a simple molecule of water, alcohol etc.
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