Polymers

Polymer is simply high molecular mass macromolecules which consist of repeating structural units. The repeating structural units are called as monomers. The process of formation of polymers from respective monomers is called polymerization.

Polymers are various types they are

1. Polymer Classification on the basis of Source:

• Natural Polymer: Protein, Cellulose, Rubber.
• Semi-synthetic Polymer: Cellulose Derivatives as cellulose acetate (Rayon), Cellulose Nitrate.
• Synthetic Polymer: Plastic (Polyethene), Synthetic Fibers ( Nylon 6-6), Buna-S.

2. Polymer Classification on the basis of Structure:

• Linear Polymer: High Density Polythene, Polyvinyl Chloride.
• Branched Chain Polymer: Low Density Polythene.
• Cross Linked or Network Polymer: Bakelite, Melamine.

3. Polymer Classification on the basis of Molecular Forces:

• Elastomers: Weak intermolecular forces. eg.- Natural Rubber, Synthetic Rubber.
• Fibers: Strong intermolecular forces. eg.- Polyamides (Nylon6-6), Polyesters (Terylene).
• Thermoplastic: Polythene, Polystyrene.
• Thermosetting: Bakelite, Urea Formaldehyde Resins.

Lower Density Polyethene  (L.D.P.) : prepared at 1000-2000 atm pressure, 350-570 Kelvin Temperature and O2 peroxide inhibitor.

Higher Density Polyethene  (H.D.P.) : prepared at 6-7 atm pressure, 333-343 Kelvin Temperature and Zieglar Natta Catalyst.

Polymers	Monomers	Monomer Formula	Use
1.    Teflon	Tetra fluroethene	CF2=CF2	Oil seals, Gasket
2.   Poly acrylonitrile	Acrylonitrile		Commercial Fibers
3.    Terylene or Decron	Ethylene Glycol Tery phthalic Acid	HOCH2-CH2OH	Commercial Fibers
4.    Nylon 6,6   And   5.    Nylon 6	Hexamethylene-diamine Adipic Acid Caprolactum	NH2(CH2)6NH2   HOOC(CH2)4COOH	Making Sheets, bristles of brushes, textile industry, tyre cords, fabrics, ropes etc.
6.    Phenol Formaldehyde Polymer
i.                  Novolac	Phenol + Formaldehyde	HCHO	Used in paints
ii.                Bakelite	Phenol + Formaldehyde	HCHO	Comb, Electric switches
7.    Malamine Formaldehyde Polymer	Malamine + Formaldehyde	HCHO	Unbreakable crockery
8.    Buna S	1,3-Butadiene + Styrene	CH2=CH-CH=CH2	Auto tyres, cables insulation, floor tiles