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POLYMERS AND PLASTICS

  • The polymer is a substance formed by the combination of two or more monomers.
  • the polymer is a greek word, poly means many, mers means parts.
  • the monomer is a simple molecule.

polymers are two types they are natural and artificial.


  • natural polymers are obtained from nature directly.
example:natural rubber,cellulose,protein,silk etc,.

  • artificial or synthetic polymer, these are formed by the combination of organic compounds.
example:nylon,bakelite,poly vinyl chloride etc,.

the process of synthesizing the polymer is nothing but polymerization.polymerization is three types:-

ADDITIONAL POLYMERISATION:


a polymer is formed by the combination of two or more monomers, without losing of by-products
example: POLYTHENE, POLYSTYRENE, POLYVINYL CHLORIDE.

CONDENSATION POLYMERISATION:


a polymer is formed by the combination of two or more monomers, with losing of by-products.
example: BAKELITE, UREA FORMALDEHYDE RESIN.

CO-POLYMERISATION:


a polymer is formed with a combination of two completely different monomers and form a new product.
example: BUNA-S RUBBER OR STYRENE RUBBER.

NATURAL RUBBER: 

it is an isoprene polymer.
example: latex from the trees.

ELASTOMER:

it is a synthetic rubber, which can be stretched up to twice its length.
example: BUNA-S OR STYRENE, NEOPRENE.

VULCANIZATION is the process of adding sulfur at 110-150 degrees Celcius to improve the quality of rubber.

PLASTICS:


  • plastics are the high molecular weight polymers formed by the applications of heat and pressure.plastics are two types:
  • thermoplastics nothing but their molecules are a linear chain.
  • thermosetting plastics nothing but their molecules have the cross-linked chain.
DIFFERENCE BETWEEN THERMOSETTING AND THERMOPLASTIC;



ALL THE EXAMPLE STRUCTURES:

the structure of isoprene or natural rubber :

the structure of  polythene:

the structure of pvc :

the structure of polystyrene:


the structure of bakelite:

the structure of urea formaldehyde:

the structure of styrene rubber or buna-s:

the structure of Teflon :

the structure of vulcanized rubber:

the processing structure of latex:

note:

  • the urea was invented by the scientist wholer. the for this compound is CH₄N₂O.

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