Polymers in simple

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Polymers in simple

  1. 1. POLYMER
  2. 2. WHAT IS POLYMER?  POLYMER IS A MARCOMOLECULE WHICH ARE JOINED TOGTHER BY SMALL MOLECULE.  EXAMPLE: POLYETHYLENE HEAT n CH2=CH2  ETHYLENE CATALYST POLYETYLENE (CH-CH2)
  3. 3. CHARACTERISTICS OF POLYMER  LOW DENSITY  GOOD MOULDABILITY  GOOD CORROSION RESISTANCE  POOR TENSILE STRENGTH  LOW MECHANICAL PROPERTIES  POOR TEMPERATURE RESISTANCE
  4. 4. CLASSIFICATION OF POLYMER  POLYMERS ARE MAINLY CLASSIFIED INTO TWO TYPES NATURAL POLYMER SYNTHETIC POLYMER
  5. 5. NATURAL POLYMER  NATURAL POLYMER ARE THE POLYMER EXIST AS NATURAL RESOURCE  SUCH AS CELLOUSE WHICH IS THE MAIN CONSITUTENT OF WOOD AND PAPER.  EXAMPLES:CELLOUSE AMINO ACIDS etc..,
  6. 6. SYNTHETIC POLYMER POLYMER MADE BY ARTIFICIALLY USING CHEMICAL ARE CALLED AS SYNTHETIC POLYMERS.  EXAMPLE:BAKELITE NEOPRENE NYLON POLYVINYL CHOLRIDE POLYSTYRENE 
  7. 7. NYLON 6-6  IT IS OTBTAINED BY POLYMERIZATION OF HEXAMETHYLENE DIAMINE AND ADIPIC ACID.
  8. 8. PROPERTIES NYLON 6:6 IS LESS SOFT AND STIFF MATERIAL.  THEY BEHAVE AS PLASTIC AS WELL AS FIBER.  THAY HAVE GOOD MECHANICAL STRENGTH.  HIGH ABRASION RESISTANCE. 
  9. 9. USES USED IN FIBERS IN MAKING SCOKS,DRESSES etc.,  USED IN MOULDING PURPOSE FOR MAKING GEAR.  USED FOR MAKING FILAMENTS IN TOOTH BRUSHES. 
  10. 10. EPOXY RESIN  IT IS PREPARED BY CONDENSING EPICHLOROHYDRIN WITH BISPHENOL.
  11. 11. PROPERTIES HIGHLY CHEMICAL RESISTANCE TO WATER,ACIDICS,ALKALIS AND OTHER CHEMICALS.  THEY ARE FLEXIBLE AND TOUGH.  POSSES VERY GOOD HEAT RESISTANCE.  POSSES EXCELLENT ADHESION QUALITY. 
  12. 12. USES EPOXY RESIN ARE USED AS SURFACE COATINGS AND ADHESIVE.  USED AS LAMINATING MATERIAL IN ELECTRICAL EQUIPMENTS.  USED FOR THE PRODUCTION OF COMPONENTS FOR AIRCRAFTS AND AUOTMOBLIES. 
  13. 13. MECHANISM OF ADDITION POLYMERIZATION  IT CAN BE EXPLAINED BY THE TWO FOLLOWING METHODS FREE RADICAL MECHANISM IONIC RADICAL MECHANISM
  14. 14. FREE RADICAL  IT OCCURS IN THREE STEPS INITIATION PROPAGATION TERMINATION
  15. 15. INTIATION  PRODUCTION OF FREE RADICAL BY HOMOLYTIC DISSOCIATION. I  2R0 INTIATOR FREE RADICAL  ADDITION OF FREE RADICAL TO THE FIRST MONOMER. 
  16. 16. PROPAGATION  GROWTH OF CHAIN INTIATING SPECIES 
  17. 17. TERMINATION  COUPLING  INVOLVES COUPLING OF FREE RADICAL ONE CHAIN END TO ANOTHER. 
  18. 18. DISPROPORTIONATION  INVOLVES TRANSFER OF HYDROGEN ATOM OF ONE RADICAL CENTRE TO ANOTHER,FORMING SATURATED AND UNSATURATED MOLECULE. 
  19. 19. IONIC MECHANISN  IT IS INITIATED BY A POSITIVE ION AND NEGATIVE ION. CATIONIC POLYMERIZATION ANIONIC POLYMERIZATION
  20. 20. CATIONIC POLYMERISATION  IT TAKES PLACE WHEN ELECTRON DONATING GROUPS LIKE PRESENT IN MONOMER. THESE GROUPS STABILISE THE CABONIUM ION FORMATION. STYRENE INTIATOR USED TO INTIATE THE REACTION ARE 
  21. 21.  INTIATOR
  22. 22. PROPAGATION  IT INOLVES THE GROWTH OF CHAIN INITIATING SPECIES. 
  23. 23. TERMINATION  IT INVOLVES THE REMOVAL OF CATALYST BY THE ADDITION OF PROTON 
  24. 24. ANIONIC POLYMERIZATION IT TAKE PLACE WHEN ELECTRON WITHDRAWING GROUP LIKE ()PRESENT IN MONOMER.  THESE GROUP STABILISE CARBANION FORMATION. ACRYLONITRILE INITIATOR USED TO INITIATE THE REACTION ARE LEWIS BASES LIKE() 
  25. 25. INTIATION IT INVOLVES THE FORMATION OF CHAIN INITIATING SPECIES.
  26. 26. PROPAGATION  IT INVOLVES THE GROWTH OF CHAIN INTIATING SPECIES. 
  27. 27. TERMINATION IT OCCURS BY ADDING AMMONIA. 
  28. 28. Presented by dhayanidhi.e gokul.s amarnath.a MUTHAYAMMAL ENGINEERING COLLEGE RASIPURAM NAMAKKAL

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