Polymers

Polymers

1. Uses

   • Manufacture of plastic buckets, cups and saucers, children’s toys, packaging bags, etc

2. Definition

   • A very large molecules having high molecular mass (103-107u)

3. Types of Classification

   • Natural
     • Found in animals and Plant.
       • Proteins, cellulose, starch, some resins and rubber
   • Semi-synthetic
     • Glucose derivatives
       • Cellulose acetate and cellulose nitrate
   • Synthetic
     • Variety of synthetic polymeters
       • Plastic, synthetic fibres and syntheirc rubber

4. Type of structure

   • Linear polymer
     • Linear structure, high density polythene and polyvinyl chloride.
   • Branched chain polymers
     • Are secondary polymer chains attached to a primary backbone.
   • Network polymers
     • Tightly linked to form a complex network of three dimensional bonds.

5. Classified by polymerisation

   • Additional
     • Formed by the repeated addition of monomer molecules possessing double or triple bonds
       • Homopolymers
       • Copolymer
   • Condensation
     • Repeat condensation reaction between two different bi-funtional or tri-funtional monomeric units

6. Classification based on molecular force.

   • Elastomers
     • Polymer with viscoelasticity, include natural rubbers, polyisoprene, etc.
   • Fibers
     • Subset of man made fibers, which are based on synthetic chemicals
   • Thermoplastic polymers
     • Material that at high temperatures becomes flexible, and solidifies when cold
   • Thermosetting
     • Permanent setting polymer as it gets hardened and sets during moulding process and cannot be softened again.