Write an essay on i) Addition polymerization and ii) Condensation polynerization.

Explanation

i) Addition Polymerization : Addition polymerization involves the self addition of unsatu-rated monomers without loss of any small molecules to form polymer.
The polymer so formed is called addition polymer .
This polymerisation , is also called chain growth polymerisation. .
In addition polymerisation ,monomers should contain donds .
This type of polymerisation can be broadly subdivided into 2 groups .
a) ionic polymerisation (cationic & anionic )
b)free radical polymerization
Addition polymerization mechanism involves three steps . They are : i) chain initiation
step ii) chain propagation step and
iii) Chain termination step.
E.g : Vinyl chloride molecules polymerises to PVC. `{:(n"("CH_(2) =overset(Cl)overset(|)CH")"to -"("CH_(2)-overset(Cl)overset(|)CH-")"_(n)),("Vinyl Chloride "PVC):}`
ii) Condensation polymerization : In this polymerisation monomers combine together with the loss of simple molecules like `H_(2)O,NH_(3)`etc. The formed polymer is called condensation polymer.
Condensation polymers are generally derived from di (or) polyfunctional monomers. This polymerization is also called step polymerization.
E.g : i) Nylon -6 ,6 is from hexamethylene diamine and adipic acid by condensation.
`{:(n{H_(2)N-(CH_(2))_(6)-NH_(2)}+n{HOOC-(CH_(2))_(4)-COOH}to),("hexamethylene diamine adipic acid" ):}`
`underset(""Nylon"-6,6)({-HN-(CH_(2))_(6)-NH-CO-(CH_(2))_(4)-CO}_(n)+2nH_(2)O)`
ii)Polyethylene terephthalate (PET) from ethtlene glycol and terephtholic acid by condensation reaction.