12th Mah State Board Syllabus

1. • Definition and Introduction.
• Types of polymers.
• Examples ; structures, formations, uses
• Degree of polymerization and molecular mass.
- Ms. Anshika Verma,
- M.Sc (Chem), M.Sc (Biotech), B.Ed,

2. INTRODUCTION
• Definition: polymers are complexes, giant macromolecules made from
the repeating units which are derived from small molecules called
“monomers”
• Derived from Greek word “poly” meaning many and ‘mer’ meaning
part or unit.
• The smallest unit of a polymer which is capable of forming at least two
bonds with others is called ‘monomer’
• Examples???

3. Classification of polymers.
1. Based on origin.
2. Based on structure.
3. Based on mode of polymerization.
4. Based on intermolecular forces.
5. Based on no. of monomers.
6. Based on biodegradability.

4.  Classification based on source:-
• On the basis of sources of polymers they are classified in three types.
a)Natural polymers –
•Polymers either obtained from plants or animal are called natural polymers.
They are called plant and animal polymers.
a) Plant polymers: derived from pant sources.
Ex. Cellulose, Jute, Natural rubber
Natural
rubber
b) Animal
polymers: derived
from animal
sources.
Ex. Wool, silk, etc.

5. b) Semisynthetic polymers –
• The polymers obtained by simple chemical
treatment of natural fibers to improve
their physical properties like lustrous nature,
tensile strength are called semisynthetic fibers
• Used in preparation of non-inflamable
photographic films, cinema films, varnishes,
etc.
• Ex. Acetate rayon, cupraammonium silk,
viscous rayon, cellulose acetate (acetate
rayon)

6. c) Synthetic fibers-
•The fibers obtained by polymerization of simple chemical
molecules in laboratory are synthetic fibers.
•Artificially prepared by polymerization of one monomer or co
polymerization of two or more monomers.
•Ex. Nylon, terylene, polyethene, polystyrene, synthetic rubber,
nylon, pvc, bakelite, teflon etc.
•Further classified as fibers, synthetic rubbers and plastics.

7.  Classification based on the structure of polymers :-
• On the basis of structure they are classified in three types –
a) Linear polymers –
• In these polymers monomers are linked with each other and form a
long straight chain.
• Formed by linking of bifunctional monomers or alkenes.
• These chains has no any side chains.
Ex. Polyethene (HDPE) , PVC, etc.
.

8. b) Branched polymers –
• They have a straigh long chain with different side
chains.
•Monomers are having 3 functional groups of already
having side chains
Ex. polypropylene (sidechain —CH3), polyethene
(LDPE).

9. c) Network or cross linked polymers –
• In these monomeric units are linked together to constitute a 3-D
network.
•The links involved are called cross links.
•They are hard, rigid .and brittle due to their network structure.
Ex. Bakelite, melamine, formaldehyde resins, vulcanised rubber etc.
Urea-Formaldehyde resin
Bakelite

10. •Classification based on
polymerization process :-
On this basis they are classified in two types
A) 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 they are integral
multiple of monomer unit.
• The monomeric units are generally
alkenes and its derivatives
• Ex. Orlon, teflon, polyethene,
polypropylene, PVC.
.
ORLON: ARTIFICIAL WOOL

11. B) Condensation polymers –
• They are formed by the combination of two
monomers by removal of small molecules like water,
alcohol or NH3.
• They have ester and amide linkage in their
molecules.
• Their molecular mass is not the integral multiple of
monomer units.
• Chain growth occurs by series of condensation steps.
Hence it is also refered as step growth
polymerization.
• Ex. Polyamides (Nylons), polyesters.

12. C) Ring opening polymers –
• Lactams, cyclic ethers, lactones polymerize by ring opening.
• Similar to addition polymerization. However in addition
polymers, the monomer is repeatedly added, however in ring
opening the cyclic structure is opened.
• Also a step growth polymerization like condensation
polymerization.

13.  Classification based on molecular forces :-
•Mechanical properties of polymers like tensile strength, toughness, elasticity
depends upon intermolecular forces like van-der waals forces and hydrogen
bonding.
A) Elastomers –
• As the stain is applied polymer get stretched and as the force is released
polymer regain its original position
• These are the polymers in which polymer chains are held up by weakest
attractive forces. The cross linking avoids tearing of the polymer.
• These polymers are elastic and called elastomers.
Ex. Neoprene, vulcanised rubber, Buna-S, Buna -N.

14. B) Fibers-
• They have high intermolecular
attractive force like H-bonding and
crystalline in nature.
•They have high tensile strength and
used in textile industries.
• Ex. Nylon-6, Nylon-66, Terylene.
Nylon examples:
Terylene examples:

15. 3) Thermoplastic and
4)Thermosetting plastics
Thermoplastics
1. They become soft on heating
and hard on cooling.
2. Can be recycled, reused.
3. Can be remolded.
4. Generally linear and
branched polymers
5. Undergo addition
polymerization.
6. Ex. PVC, polyethene, PAN,
polystyrene, PP, etc.
Thermosetting plastics
1. They do not become soft on
heating
2. Cannot
3. Cannot
4. Generally cross linking/network
polymers.
5. Undergo condensation
polymerization.
6. Ex. Nylons, Terylene, Bakelite,
etc.

16. •Classification based on NO.
OF MONOMERS involved in
the polymer:-
1)Homopolymer-
• These are composed of ONLY one
type of monomer.
Ex. Polyethene, PVC, PP, Polypropylene,
2) Heteropolymer-
 These are composed of more than one
type of monoomer.
 These are called co-polymers.
 Ex. Nylon, Buna – N, Buna-S, Terylene,
etc.

17.  Classification based on
degradability:
1. Non- Biodegradable
polymers.
• Not affected by micro organisms.
• Accumulate in the environment for long
time and cause pollution hazards.
• Ex. Polythene, polystyrene, etc.
2. Biodegradable polymers.
• Degraded by microbes.
• Environment friendly.
• Ex. PHBV, Nylon 2,6 , Dextran, etc.

19. IMPORTANT POLYMERS:
1. NATURAL RUBBER.
• Monomer: Isoprene ( 2- methyl buta-
1,3-diene)
• Linear polymer of isoprene.
• Undergoes addition polymerization.
• Properties:
 Has Cis configuration.
 Exhibits elasticity.
• Trans isoprene is called “Gutta-
Percha” which is crystalline and non
elastic.

21. VULCANIZATION OF RUBBER:
1. Process to improve the physical
properties of natural rubber (toughness,
elasticity, tensile strength, etc.)
2. Discovered by Charles Goodyear in
1839.
3. The process by which a network of
cross linking is introduced into the
elastomers is called vulcanization.
4. Generally Sulfur is used to form cross
linking resulting in improved properties.
5. More the % of S, harder will be the
rubber.
6. Ex. 1-3% sulfur: Rubber bands.
3-10% Sulfur: Tyres.

22. 2. POLYETHENE.
a) LDPE ( LOW DENSITY POLYETHENE).
• It is a branched polymer obtained by
polymerization of ethene under 1000-2000 atm
pressure and 350-570 K temperature in
presence of trances of O2/peroxide as initiator.
• Involves free radical mechanism.
• The terminal carbon atom of growing chain
abstracts a H atom to for a 2o free radical
resulting in the branching
• Properties:
 Flexible but tough
 Chemically inert
 Low density and melting point ( 110oC)
 Poor conductor of electricity.
• Uses:
 Pipes, insulation in cables,
 Packaging – squeeze bottles, containers,
etc.

23. b) HDPE (HIGH DENSITY
POLYETHENE).
• Linear polymer obtained by
polymerization of ethene under 6-7
atm pressure and 333-343 K
temperature in presence of
“Zieglar –Natta catalyst”
(combination of titanium
tetrachloride and triethyl aluminium)
• Properties:
 High tensile strength.
 High density and melting point
( 144 - 150oC)
 More resistant to chemicals
and stiffer than LDPE.
• Uses:
 Toys, buckets, dustbins,
bottles, pipes, etc.

24. 3. TEFLON (POLYTETRA FLURO
ETHYLENE):
• Monomer: Tetra fluro ethylene/ethene.
• Polymerization takes place using free radical
initiators such as hydrogen peroxide or
ammonium persulphate at high pressure.
• Properties:
 Tough, chemically inert,
 Resistant to heat.
 Resistant to attack by
corrosive agents.
• Uses:
 Making non stick cookware
 Oil seals.
 Gaskets, etc

25. 4. ORLON (POLYACRYLONITRILE/ PAN/ ACRILAN):
• Monomer: Acrylonitrile
• Prepared by polymerization of acrylonitrile using peroxide as initiator.
• Uses:
 Artificial or substitute for wool.
CH2 = CH – CN
Acrylonitrile.

26. 5. POLYAMIDES:
• Obtained by condensation between
dicarboxylic acid and diamine.
a. NYLON 6,6
• Monomers: Adipic acid
hexamethylene diamine.
• Number 6, 6 denote two monomers each
having 6 carbon atoms.
• Properties:
 Linear condensation polymer.
 High tensile strength
 Does not soak in water.
• Uses:
 Making sheets
 Bristles of brushes,
 Surgical sutures,
 Textile fabrics
 Ropes, fishing nets, etc.

27. b. NYLON 6
• Monomer: έ – Caprolactum.
• Shows ring opening polymerization
• Number 6 represents a single monomer
having 6 carbon atoms..
• Properties:
 High tensile strength
 Luster.
• Uses:
 Tyre cords.
 Ropes
 Fabrics

28. 6. POLYSTER ( TERYLENE/ PET/
DACRON
• Monomer: Ethylene glycol
Dimethyl Terepthalate (DMT)
• Obtained by condensation
polymerization between the monomers
at high temperature.
• Properties:
 High M.P (265oC)
 Resistant to chemicals and water.
• Uses:
 Making wrinkle free fabrics
 Blended with cotton: Terycot
 Blended with wool: Terywool
 PET: making bottles, containers,
etc.

29. 7. OTHER FORMALDEHYDE POLYMERS:
A.BAKELITE.
• Monomers: Phenol.
Formaldehyde.
• Monomers react in presence of acid or base catalyst to form thermosetting moulding
polymer “NOVOLAC” in two stages.
• In the third stage, novolac undergoes polymerization at high temperature of 138-
176oC and high pressure to form Bakelite. During this stage, crosslinks are formed
resulting in a rigid 3-D polymeric material i.e. Bakelite.
• Properties:
 High tensile strength.
 Insoluble and infusible.
• Uses:
 Making telephonic instruments.
 Kitchenware.
 Electric insulators.
 Handles of cookware.
 Switches.

31. B. FORMALDEHYDE – MELAMINE POLYMER.
• Monomers: Melamine
Formaldehyde.
• Condensation polymer.
• Used to make crockery.

32. 8. BUNA –S (SBR)
• Monomers: Styrene
Butadiene.
• Addition polymerization carried about by Na.
• Superior to natural rubber in terms of
abrasion resistance and mechanical strength.
Hence used in tyre making.

33. 9. NEOPRENE.
• Monomers: Chlroprene
(2- Chloro Buta -1,3- diene)
• Addition polymer which polymerizes in
presence of oxygen.
• Vulcanization of neoprene takes place in
presence of MgO.
• Properties:
 Resistant to petroleum,
vegetable oils, light and heat.
• Uses:
 Making pipes for transport of
gasoline.
 Insulator cables.
 Belts for power transmission.
 Conveyor belts.

34. 10. VISCOSE RAYON.
• Cellulose (wood pulp) – con. NaOH –
alkali cellulose.
• Next, treated with carbon disluphide –
xanthate.
• Next, treated with dil. NaOH –
visocose solution – acid bath-
regenrated cellulose fibers
precipitate.

35. BIODEGRADABLE
POLYMER:
PHBV
• Monomers: β- Hydroxy butyric acid.
β- Hydroxy valeric acid.
• Condensation, co polymer.
• Aliphathic polyester named “β-
Hydroxy butyrate- co - β- Hydroxy
valerate.