2. Contents
Some Basic Definitions
Classification Of Polymers
1. By Origin
2. By Monomer
3. By Thermal Response
4. By Mode Of Formation
5. By Structure
6. By Application & Physical Properties
7. By Tacticity
Reference
3. Definition
The word ‘polymer’ comes from the Greek
words poly (meaning ‘many’) and meros
(meaning ‘parts’).
Example: POLYETHYLENE =
(ETHYLENE+ ETHYLENE+......)n
Where n = 4,000
Polymers are very large molecules made when hundreds of
monomers join together to form long chains.
4. Monomer
The small individual repeating units/molecules
are known as monomers(means single part).
Imagine that a monomer can be represented by
the letter A. Then a polymer made of that
monomer would have the structure:
-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-
5. Polymerization
• The process by which the monomer molecules
are linked to form a big polymer molecule is
called ‘polymerization’.
• Polymerization is a process of bonding monomer,
or “single units” together through a variety of
reaction mechanisms to form longer chains
named Polymer
• As important as polymers are, they exist with
monomers, which are small, single molecules
such as hydrocarbons and amino acids.
6. Classification Of Polymers
1. By Origin
2. By Monomer
3. By Thermal Response
4. By Mode Of Formation
5. By Structure
6. By Application & Physical Properties
7. By Tacticity
7. By Origin
Natural Polymers
Polymers which are isolated from natural
materials are called as natural polymers.
E.g. Silk, Wool, Natural rubber, Cellulose,
Starch, Proteins etc.
9. Semisynthetic Polymers
The polymers obtained by simple chemical
treatment of natural polymers to improve
their physical properties like lustrous nature,
tensile strength are called semisynthetic
polymers
E.g. Cellulose acetate, Cellulose nitrate
10. Synthetic Polymers
Polymers synthesized in laboratory from low
molecular weight compounds, are called as,
synthetic polymers.
E.g. Nylon, Terylene, Polyethylene, Polystyrene,
Synthetic rubber, Nylon, PVC, Bakelite, Teflon etc.
11. By Monomer
Homo Polymers
A polymer consist of identical monomers is
called homo polymer.
E.g. Polyethylene, PVC, Polypropylene, Nylon 6
Co Polymers
A polymer consist of monomers of different
chemical structure are called copolymers.
E.g. Nylon 6,6
12. By Thermal Response
Thermoplastic Polymers
They are easily moulded in desired shapes by heating
and subsequent cooling at room temperature.
They are soft in hot and hard on coding.
They my be linear or branched chain polymers.
E.g. PE, PVC, PS, PP
13. Thermosetting Polymers
This polymer is hard and infusible on heating.
These are not soft on heating under pressure and
they are not remolded.
These are cross linked polymers and are not
reused.
E.g. Bakelite
14. By Mode Of Formation
Addition Polymers
The polymers formed by the addition of
monomers repeatedly without removal of by
products are called addition polymers.
These polymers contains all the atoms of
monomers hence their molecular weight are
integral multiple of monomer unit.
E.g. Teflon, Polyethylene, Polypropylene, PVC.
15. Condensation Polymers
They are formed by the combination of two
monomers by removal of small molecules like
H2O, Alcohol or NH3. Their molecular mass is not
the integral multiple of monomer units.
They have ester and amide linkage in their
molecules.
E.g. Polyamides(Nylons), Polyesters(PET)
16. By Structure
Linear Polymers
In these polymers monomers are linked with
each other and form a long straight chain.
These chains has no any side chains.
Their molecules are closely packed and have high
density, tensile strength, and melting point.
E.g. HDPE, Nylons
17. Branched Polymers
They have a straight long chain with different
side chains.
Their molecules are irregularly packed hence
they have low density, Tensile strength and
melting point.
E.g. LDPE, LLDPE
18. Cross-linked Polymer
In these monomeric units are linked together to
constitute a 3D network.
The links involved are called cross links.
They are hard, rigid .and brittle due to their
network structure.
E.g. Bakelite, Melamine, Formaldehyde resins,
Vulcanized rubber
19.
20. By Applications & Physical Properties
Fibers
If polymer is drawn into long filament like
materiel whose length is at least 100 times it’s
diameter, are said to be converted into fiber.
They have high tensile strength because of high
intermolecular attractive force like Hydrogen
bonding.
Highly crystalline.
E.g. Nylon, Terylene.
21. Plastics
Polymer is shaped into hard and tough utility
articles by application of heat and pressure, is
known as plastics.
Here the intermolecular force between
polymeric chains are intermediate between
elastomers and fibers.
They are partially crystalline.
E.g. Polystyrene, PVC, PMMA
22. Elastomers
They are solids with rubber like elastic
properties.
Here the polymeric chains are held together by
the weakest intermolecular forces so they are
highly amorphous in nature.
These weak binding forces permit them to be
stretched.
E.g. Natural rubber, BUNA-S, BUNA-N,
Vulcanised rubber
23.
24. Resins
Low molecular weight.
Polymers which are used as adhesives, sealants
etc., in a liquid form are described as liquid
resins.
E.g. Epoxy adhesives and polysulphides sealants.
25. ByTacticity
Tacticity simply means deposition of
side groups in space.
The head to tail configuration in which the functional groups are
all deposited on the same side of the chain, is called isotactic
polymers.
If the deposition of side groups is in alternating fashion, it is called
synditactic polymers.
If the deposition of side groups are at random around the main, it
is called atactic polymers.
26. Other Parameters Of Classification
By Crystallinity
1. Crystalline – Monomers arranged in ordered way.
2. Amorphous – Monomers arranged in random way.
By Backbone Atom
1. Organic – Polymer Backbone is made-up of carbon atom.
2. Inorganic – Polymer Backbone is made-up of other atoms
27. References
Polymer Science - Gowariker V. R., New age
International Publishers
Textbook of Polymer Science - Billmeyer F. W,
Wiley India Publishers
Advanced Polymer Chemistry – Manas Chanda
Marcel Dekker INC.