POLYMERS

• Giant Molecules - called polymers are made up by the linkage of simpler molecules.
• • Proteins, nucleic acids, glucose -The most well known natural polymers are
• Polymer is a molecule, made from joining together many small molecules called

  monomers.
• Poly means many
• Mer means unit
• Polymers may be naturally found in plants and animals (natural polymers)
• man-

  made (synthetic polymers).
• Polymers are all created by the process of polymerization
• Classification of Polymers based on origin

  • Natural
  • Synthetic
• Natural Polymers - They occur naturally and are found in plants and animals.
• What do you call a biodegradable polymers? - biopolymers
• Plastic - is the most common and

  widely used synthetic polymer.
• Classification of Polymers based on chemical structure

  • homopolymer
  • copolymer
• Homopolymer – polymer which consists of one type of monomer
• Copolymer – a polymer which is derived from more than one type of monomer.
• Classification of Polymers based on polymeric structure

  • linear
  • branched-chain
  • cross-linked
• Linear - The structure of polymers containing long and straight chains fall into this category.
• Branched-chain - When linear chains of a polymer form branches.
• Cross-linked - They are composed of bifunctional and trifunctional

  monomers.
• Classification of Polymers based on arrangement of monomers

  • Block
  • graft
• Block polymer – consists of relatively long sequences of identical monomer units
• Graft polymer – branched polymer whose backbone is formed from one type of monomer and branches are formed from other type of monomer
• Classification of Polymers based on tacticity

  • Isotactic
  • Syndiotactic
  • Atactic
• Isotactic – side groups of the polymer lie on the same side of the chain
• Syndiotactic – side groups of the polymer are arranged in an alternate

  manner
• Atactic – side groups are arranged in an irregular or random manner

  around the main chain
• Classification of Polymers based on thermal behavior

  • thermoplastics
  • thermosets
• Thermoplastics – polymers which are easily softened upon heating
• Thermosets – polymers which change irreversibly into hard and rigid materials on

  heating and cannot be reshaped
• Classification of Polymers based on molecular forces

  • Elastomers
  • fibers
• Elastomers – polymers which can be easily stretched by applying small stress
• Fibers – polymers which have strong intermolecular forces between the polymer

  chains
• Classification of Polymers based on modes of synthesis

  • addition
  • condensation
• Addition polymers – these polymers are formed when same monomers are added –

  these monomers are usually alkenes (hydrocarbons that contain double bonds)
• Condensation polymers – these polymers are formed when two monomers react

  with the elimination of smaller molecule (usually water, ammonia, methanol, or

  hydrogen chloride)
• Cellulose – polymer made up of long strands of glucose, which is also called

  the “polysaccharide”.
• Starch – another polymer made up of glucose monomer units.
• Rubber – is a polymer that is obtained as a milky white fluidknown as latex from a tropical rubber tree. It is made up of Isoprene

  monomer units.
• Polymer made up of monomer units called

  “nucleotides”. DNA is found in nearly all living cells.
• Proteins make up our hair and muscles.