A copolymer is a polymer formed when two (or
more) different types of monomers are linked in the
same polymer chain, as opposed to a
homopolymer where only one monomer is used.
- Dr. Siju N Antony
A and B alternate in polymer chain
large blocks of A units alternate with
large blocks of B units
A and B randomly positioned along
chains of B units grafted onto A backbone
Copolymers two or more monomers polymerized together
If monomer A has interesting properties, and monomer B has (different) interesting properties,
making a “mixture” of monomers should lead to a superior polymer
3. Types of Copolymers
Alternating copolymer styrene – maleic anhydride copolymer
Random copolymer styrene – butadiene
Block copolymer polystyrene-b-poly(methyl methacrylate)
Graft copolymer polystyrene grafted on polybutadiene
4. Styrene and Acrylonitrile are added to polybutadiene latex and the
mixture is warmed to about 50°C to allow absorption of the
Water soluble initiator potassium persulphate (K2S2O8) is added to
polymerize styrene and Acrylonitrile.
The resultant materials will be a mixture of Polybutadiene,
polybutadiene grafted with Acrylonitrile and Styrene, and Styrene-
5. The nitrile groups from neighboring chains, being polar, attract each other and
bind the chains together, making ABS stronger than pure polystyrene.
Preparation of ABS
6. Why do you combine Acrylonitrile, Butadiene
Chemical and Solvent resistance
Generally resistant to alkalis and acids but not concentrated oxidizing
Dissolved by many aromatic and chlorinated hydrocarbons, esters and
High impact resistance, good stiffness, tough, hard, ductile, excellent
surface quality, high dimensional stability at elevated temperatures.
Disadvantages - lack of transparency, poor weathering resistance
Radiator grills, head light housing, seat belt, head lamp
fixtures, door knobs, two wheeler front noise, water panel,
helmet, electroplated parts, mirror housing and wheel covers.
In the vehicle construction industry.
Drinking water system, water vent systems and
Plumbing fixtures, table edging, sliding doors, window
trucks, refrigerators liners, refrigerator door handles,
pipe fittings, ventilator system components, picnic boxes,
food processors, coffee maker leads, microwave oven tops.
IV fluid monitoring controllers, blood glucose meter,
surgical clips, emergency intravenous infusion pump,
scanner body, ECG / EEG body frames, cabinets for
medical kit, breathing exerciser.
Kevlar is a very strong material – about five times
stronger than steel.
Possess high tensile strength, low weight and high
High cut resistance, fracture resistance and flame
very poor compressive strength (resistance to squashing or
squeezing). That's why Kevlar isn't used instead of steel as a
primary building material in things like buildings or bridges,
and other structures where compressive forces are common.
16. Conducting Polymers
A polymer having conductance similar to that of a conductor is called a
Merits - light weight, corrosion resistance and greater workability
17. • Intrinsically conducting polymers : These types
of polymers have a solid backbone made up of
extensive conjugated system, which is
responsible for conductance.
• Extrinsically conducting polymers : Those
conducting polymers which owe their
conductivity due to the presence of externally
added ingredients in them are called
extrinsically conducting polymers.
Poly aniline is a semiconductor and it becomes
a good conductor upon doping.
Light weight, metallic lusture and flexibility
They show three distinct oxidation states.
leucoemeraldine – white; emeraldine – green for the emeraldine
salt, blue for the emeraldine base; pernigraniline – blue/violet
More noble than copper
Stable in air, soluble in some organic solvents
20. Used as bio-sensors, humidity sensors, gas sensors
and radiation sensors since oxidised and reduced
forms of polyaniline have different colours.
Used as electrode material for rechargeable
Used as conductive track in PCBs.
Used in anodic passivation of metals to control
Used in smart windows which controls the entry of
• Polypyrrole films are yellow but darken in air
due to oxidation
• Doped films are blue black
• They are amorphous
• Polypyrrole is an insulator but oxidative
derivatives are good conductors.
• Its conductivity increases with rise in
• Good chemical resistance and thermal
• Doping makes it brittle.
• Used in biosensors, gas sensors, smart windows
and light weight rechargeable batteries
• Used in drug delivery
• Corrosion protection
• Used in carbon composites
• Used in antielectrostatic coatings
• Used for testing blood lithium levels
An organic light-emitting diode (OLED) is a light emitting diode (LED) in which the emissive
electroluminescent layer is a film of organic compound that emits light in response to an electric current. This
layer of organic layers is situated between two electrodes; typically, at least one of these electrodes is
(Indium Tin Oxide)
25. How does it work?
• Apply potential difference across the anode and cathode
terminals (the cathode receives electrons and anode loses
electrons or receives holes)
• As a result the emissive layer becomes excessively negatively
charged and conductive layer becomes positively charged. Thus
the scenario at the junction of emissive and conductive layers
will resemble a p-n junction.
• Recombination of electrons and holes takes place at the
emissive layer with the liberation of energy in the form of light.
• Wavelength of the light emitted depends on the type of emissive
material and the intensity of the light depends on the applied
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• They are very thin (0.2-0.3mm)
• They are brighter and need no backlight
• Consumes less power and hence preferred for cell
phones (better battery life)
• Gives better colour even when viewed from side
• Poor life span
• Organic molecules are sensitive to water