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### Addition polymerization Explain polymerization by addition with an example. It is the process in which monomers undergo addition, repeatedly resulting in the formation of long chain polymers without elimination of simple molecules like H₂O, HCl, and NH₃. **Examples** **(a)** Formation of pol...

### Addition polymerization Explain polymerization by addition with an example. It is the process in which monomers undergo addition, repeatedly resulting in the formation of long chain polymers without elimination of simple molecules like H₂O, HCl, and NH₃. **Examples** **(a)** Formation of polyethylene from ethylene - Ethylene - Free radical (unstable monomer) - Monomer - Monomer - Dimer - Trimer - Polyethylene (Polymer) **OR** - n(C₂H₄) Ethylene - Heat, light, pressure and catalyst -(C₂H₄) Polyethylene (or polythene) In the addition polymerization, monomers which are taking part in polymerization must contain at least one double bond. - One of the two bonds between two carbon atoms of ethylene molecule (CH₂ = CH₂) is open up (brakes) with the formation of an unstable molecule of ethylene (-CH₂-CH₂-). - As one bond brakes the two valence electrons of a carbon atom become free. - The unstable molecule (free radical) combine with similar molecule (monomer) to form a dimer. ### Formation of Teflon (PTFE) Tetra-fluoro ethylene, (CF-CF₂) undergoes addition polymerization in the presence of oxygen to form polytetra-fluoro ethylene (PTFE) - n(Tetrafluoro ehtylene) -(Polytetrafluoroethylene) or (Teflon) ### Formation of polystyrene (PS) Styrene, (CH₃CH CH₂) undergoes addition polymerization to form polystyrene. Polystyrene is a cheap transparent compound. - Styrene - Polystyrene ### Formation of poly-vinyl chloride (PVC) Poly-vinyl chloride is obtained by the addition polymerization of vinyl chloride (CH₂ = CH -CI) using hydrogen peroxide (H₂O₂) as a catalyst. - Vinyl chloride - Poly-vinyl chloride or PVC ### Condensation polymerization It is a process in which the different types of monomers are joined together by condensation forming a large polymer with the elimination of molecules such as H₂O, HCl, CH₃OH etc. **Examples** ### Formation of Nylon 6:6 Hexamethylene diamine and adipic acid undergo condensation polymerization with the elimination of a water molecule to form Nylon 6:6.