Polyenes and copolymerisation.

Polyenes

• Polyenes are polyunsaturated organic compounds that contain atleast three alternating double and single carbon-carbon bond. For example polyacetylene, β - carotene.

  

  Example of polyene; polyacetylene.
• These carbon - carbon double bond undergoes an interaction known as conjugation which lead to unusual optical properties of polyenes.
• Some polyenes are bright in colour which is unusual in hydrocarbons.
• β-carotene is responsible for the orange colour of carrots.
• Polyenes are more reactive than simple alkenes and they also have high electrical conductivity.
• Dienes are related to polyenes in which there is two alternating double and single carbon-carbon bonds.

Copolymerisation

Check out kinetics of copolymerisation also.

The polymers containing two or more different monomers are called  Copolymers  and  the process of formation of Copolymers is called copolymerisation. Nylon 6,6 is a copolymer.

Let A and B be two monomers. The different types of Copolymers are

1) Random (or Statistical) Copolymers:

In these polymers, the monomers are attached randomly as

Random copolymer.

2) Alternating Copolymer:

Here the two monomers are arranged in an alternating manner as

Alternating Copolymer.

3)Block Copolymer:

Here a long sequence or block of one monomer is attached to the block of second monomer as

Block copolymer.

4)Graft Copolymer:

Here a chain of one monomer is attached to the backbone (main chain) of another monomer as

Graft Copolymer.