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.

Properties:-

  • Low density polyethene is a transparent polymer of moderate tensile strength and high toughness.
  • It is a poor conductor of electricity

Uses:-

  • 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.

Uses:-

  • 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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CBSE Class 12 Chemistry Polymers All Topic Notes CBSE Class 12 Chemistry All Chapters Notes

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