Monday, 12 May 2014

12 Class Chapter 15- Polymers

Polymer & Polymerization

Condensation Polymer: Nylon-6-6, Terylene.
Addition Polymer: Polythene, Neoprene.

Polymer Classification

Polymer Classification on the basis of Source:

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

Polymer Classification on the basis of Structure:

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

Polymer Classification on the basis of Molecular Forces:

1.    Elastomers: Weak intermolecular forces. eg.- Natural Rubber, Synthetic Rubber.
2.    Fibers: Strong intermolecular forces. eg.- Polyamides (Nylon6-6), Polyesters (Terylene).
3.    Thermoplastic: Polythene, Polystyrene.
4.    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
Tetrafluroethene
CF2=CF2
Oil seals, Gasket
2.    Polyacrylonitrile
Acrylonitrile

Commercial Fibers
3.    Terylene or Decron
Ethylene Glycol
Teryphthalic 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

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