Plastics are synthetic resins which are rapidly becoming important in everyday life. These are classified into two types: 
Thermosetting plastics 


 These are the plastics which can easily be softened when heated and become hard when cooled with a little change in their properties. When heated they melt and form a fluid which can be moulded into any desired shape and then cooled to get the desired product. Common examples are polythene, polypropylene, polyvinyl chloride etc. 

Thermosetting Plastics

 These are the plastics which undergo permanent change on heating. When heated they get highly cross linked to form hard, infusible products. Common examples are bakelite, melamine etc.

 Methods of preparation and uses of plastics 


 It is prepared by the polymerization of ethjfrie under high pressure and in the presence of traces of oxygen (0.01 %) 
 nCH2 = CH2 ► —{-H2C— CH2)t- 
It is used in the manufacture of pipes, laboratory apparatus, bottles, buckets, toys and electrical insulators. 

  Polyvinyl chloride (PVC) 

It is prepared by the polymerization of vinyl chloride (CH2=CHCI) in an autoclave PVC is used: in the manufacture of rain coats and hand bags. for artificial flooring. as a good insulating material for wires and other electrical goods. 


 It is prepared by the polymerization of styrene in the presence of benzoyl neroxide. It is resistant to shock and chemical action. It is used for: making hot drink cups, toys, combs, etc. making radio and television bodies. Making tiles to be used in covering ceilings and floors. Teflon (Polytetrafluoroethylene) It is prepared by the polyemerization oftetrafluoroethylene. Pressure It is used in the manufacture of non-stick utensils. 


 It is prepared by the polymerization of phenol and formaldehyde. It is used for making combs, fountain pens, formica, tabletops and electrical goods.

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