harathi

STRUCTURE AND PROPERTIES OF POLYMER

BY

HARATHI.J

INTRODUCTION

• Polymer and polymerisation.

• Types of monomers.

• Types of polymerisation.

• Types of polymers.

• Uses

Polymer and Polymerisation

A long molecule made up from lots of small molecules called

monomers.

Combinging large no.of monomeric units to form a

polymer is known as poolymerisation

All the same monomer

• Monomers all same type (A)

• A + A + A + A • -A-A-A-A-• eg poly(ethene)

polychloroethene PVC

Different monomers

• Monomers of two different types A + B

• A + B + A + B -A-B-A-B-• eg polyamides • polyesters

TYPES OF POLYMERISATION

1.Addition polymerisation2.Condensation polymerisation

• Free radical,ionic-cationic and anionic,coordination

Elastomers, plastics & fibres

• Examples:

Thermoplastics (80%)

• No cross links between chains.• Weak attractive forces between chains broken by

warming.• Change shape - can be remoulded.• Weak forces reform in new shape when cold.

Thermosets

• Extensive cross-linking formed by covalent bonds.• Bonds prevent chains moving relative to each other. • What will the properties of this type of plastic be like?

Crystalline polymers• Areas in polymer where

chains packed in regular way.

• Both amorphous and crystalline areas in same polymer.

• Crystalline - regular chain structure - no bulky side groups.

• More crystalline polymer - stronger and less flexible.

Cold-drawing

• When a polymer is stretched a ‘neck’ forms.• What happens to the chains in the ‘neck’?• Cold drawing is used to increase a polymers’

strength. Why then do the handles of plastic carrier bags snap if you fill them full of tins of beans?

POLYMERS USED IN1.plastic pipes, industries machines

2.electric insulators,medicines3.in suitcases , purses, school bags e.t.c,………

I AMTHANKFULL TO CORRESPONENT WHO GAVE ME THIS OPPURTUNITY AND ALSO FOR PRASAD SIR AND NALINI MAM WHO ENCOURAGED AND ME TO DO THIS PROJECT.

MY SPECIAL THANKS WHO HELPED ME LOT AND FOR AUDIENCE FOR PATIENCE LISTINING

THANKING YOU