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## Polymerization and Condensation Polymerization ### Differentiate between addition polymerization and condensation polymerization | Sr. No. | Polymerization and Condensation Polymerization | Addition Polymerization | Condensation Polymerization | | :------ | :--------------...

## Polymerization and Condensation Polymerization ### Differentiate between addition polymerization and condensation polymerization | Sr. No. | Polymerization and Condensation Polymerization | Addition Polymerization | Condensation Polymerization | | :------ | :-------------------------------------------- | :----------------------------------- | :------------------------------------ | | 1 | | It is the process in which monomers undergo addition repeatedly resulting in formation of long chain polymers without elimination of molecule like H₂O, HCl and HNO₃. | It is the process in which different types of monomers are joined together by condensation forming a large polymer with elimination of molecules such as H₂O, HCl and CH₂OH. | | 2 | | The polymers formed are linked by weak covalent bonds. | The polymers formed are linked by strong covalent bonds. | | 3 | | The polymers are usually soft, weak and less brittle. | The polymers are usually hard, strong and more brittle. | | 4 | | The polymers formed by this process are known as thermoplastics having smaller molecular weight. | The polymers formed by this process are known as thermosetting plastics having higher molecular weight. | | 5 | | Polymers can be reclaimed from wastes. | Polymers cannot be reclaimed from wastes. | | 6 | | Examples: Polyethylene, PVC, polystyrene etc. | Examples: Bakelite, polyesters. | ### Formation of phenol-formaldehyde Resin (Bakelite) Explain the formation of Bakelite plastic by condensation polymerization. Bakelite is produced by condensation polymerization of phenol (C₆H₅OH) and formaldehyde (HCHO) in the presence of acidic / alkaline catalyst. The initial reaction results in the formation of mono, di and trimethyl phenols depending upon the mole ratio of phenol to formaldehyde, catalyst, temperature and the time of reaction. The reaction proceeds by the formation of the following compounds: - Phenol - Mono methylol phenol - Dimethylol phenol - Trimethylol phenol This is followed by condensation reaction between these compounds with elimination of water to form a cross-linked polymer which is known as bakelite. The structure of bakelite is shown in the image.