Polymers

Polymers

1. Backbone of 4 major industries

   • Plastics
   • Elastomers
   • Fibres
   • Paints and Varnishes

2. Polymer means...

   • Very large molecules having high molecular mass

3. Macromolecules, formed by:

   • Joining of repeating structural units on a large scale.
     • These are derived from simple & reactive molecules known as monomers.
       • Monomers are linked by covalent bonds.

4. Polymerisation

   • Is the process of formation of polymers from monomers

5. Classification based on source

   • Natural Polymers
     • Found in plants and animals
   • Semi-synthetic Polymers
     • Cellulose derivatives (acetate and nitrate)
   • Synthetic Polymers
     • Plastics ( polythene), fibres (nylon 6,6), and rubber (Buna-S) used in daily life & industry

6. Structures

   • Linear
     • Long and straight chains
   • Branched Chain
   • Cross-Linked or Network
     • Formed from bi-functional and tri-functionsl monomers contain strong covalent bonds

7. Classifica- tion Based on Mode of Polymerisa-tion

   • Addition polymers
     • Chain growth polymerization
   • Condensation Polymers
     • Where where smaller monomers react with each other to form structural units while releasing by products such as water or methanol molecule.

8. Classification Based on Molecular Forces

   • Fibers
     • Thread forming solids with strong intermolecular forces
   • Elastomers
     • Rubber and held by weak intermolecular forces
   • Thermoplastic Polymers
     • Linear, softens whit heating and hardens with cooling. Their intermolecular forces are between fibres and elastomers
   • Thermosetting Polymers
     • Cross linked and cannot be reused

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