A polymer is formed from small molecular units called monomers that join together in long chains through chemical bonds. There are different types of polymers classified by their monomer structure and occurrence. Common synthetic polymers include plastics like polyethylene, polyvinyl chloride, and epoxy resin. These polymers have various applications due to their properties such as corrosion resistance, low cost, and ability to be molded into complex shapes.

1. •Polymers: A polymer is a long molecule formed by joining together of thousands
of small molecular units by chemical bonds.
•Monomers: Small molecules which combine together to formpolymermolecules
are known as Monomers.
•Polymerization: The chemical process leading to the formation of polymer is
known as Polymerization.
Poly=many,
Mere = parts or units
mono =single
Mere = parts or units.
Definition: Basic concepts

2. Plastic
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•Plastic is a synthetic material made from a wide
range of organic polymers such as polyethylene,
PVC, nylon, etc.
•That can be molded into shape while soft, and
then set into a rigid or slightly elastic form.

3. Properties of Plastic
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•Less brittle than glass ,hence can be made
transparent and smooth.
• Corrosion resistance
•Low electrical and thermal conductivity, insulator
•Easily formed into complex shapes, can be formed,
casted and joined.
•Wide choice of appearance, colors and
transparencies
•Light weight but posses good strength and rigidity.
•Low moisture absorption.
•Heat resistance.

4. Polymers: A polymer is a long molecule formed by joining together of
thousands of small molecular units by chemical bonds

5. Monomers: Small
molecules which
combine together to
form polymer
molecules are known
as Monomers

7. Classification Based on Monomers
Homomer: In this type, a single type of monomer unit is present.
For example, Polyethene
Heteropolymer or co-polymer: It consists of different type of monomer units.
For example, nylon -6, 6

8. Polymers classification on their structure

9. On the basis of occurrence :
1. Natural polymers : Starch, Cellulose
2.Synthetic polymers: Plastics ,rubbers ,fibers.

10. 1.Thermoplastics:
are the polymers that become soft on heating and hard on cooling and the process
can be repeated for a number of times.
They undergo reversible changes on heating.
Examples: Polythene (PE), polypropylene (PP), polyvinyl- chloride (PVC),
Thermoplastics –
• are formed by addition polymerisation
• consists of linear polymer chains with negligible cross-linking
• are soft and less brittle.
• are soluble in organic solvents.
• soften on heating and hence are enable for moulding into any shape in the hot
condition on cooling, the resin becomes hard and rigid and retains the moulded
shape.
• can be reheated and moulded into any other shape reversibly any number of
times without any change in the chemical nature.

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Polyethylene
Polyethylene is the simplest of all commercial
polymers, and yet, it is the most popular plastic in
the world.
Properties:
1. It is a rigid, waxy, material
2. non-polar material
3. It has chemical resistance to strong acids, alkalis
and salts at room temperature.
4. Good insulator of electricity.
5. It is a branched polymer.

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Polyethylene
Applications:
• It is used as a film for
packaging food, clothing, and
hardware.
• Most commercial trash bags,
sandwich bags, and plastic
wrapping are made from
polyethylene films.
• Polyethylene is also used for
everything from seat covers to
milk bottles, pails, pans, and
dishes.

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Polyvinyl chloride (PVC)
Preparation:

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Properties:
1. It is odorless, colorless, chemically inert.
2. Insoluble in hot acids, alkalis ; soluble in hot
ethyl chloride.
3. Undergo degradation in the presence of heat
and light.
Polyvinyl chloride (PVC)

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Applications:
PVC known under different trade names – tygon,
vinylite, velon, geon.
1. Un plasticized PVC is used in pipes, tubes,
helmets, light fittings, automobiles mudguards.
2. Plasticized PVC is used in table cloths, curtains,
rain-coats, insulation of electric cables.
3. Healthcare components such as temporary blood
storage and dialysis devices.
Polyvinyl chloride (PVC)

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TEFLON
Preparation : of Polytetrafloroethylene (PTEE) or
Teflon or Fluon

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Properties of Teflon:
1. High softening point (about 350̊ C)
2. High density
3. High thermal stability
4. High chemical resistance
5. Good electrical insulators
6. Mechanical properties do not change over prolonged
periods even at high temperature.

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Applications of Teflon
Applications:
1. Used for electrical insulation of wires and cables
2. Used in the making of non-stick frying pans,
stop cock for burettes.
3. Used as solid lubrication film.

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Epoxy resin
•Epoxy resin is defined as a molecule
containing more than one epoxide groups.
•The epoxide group also termed as, oxirane or
ethoxyline group.
•There are two main categories of epoxy
resins, namely the glycidyl epoxy, and non-
glycidyl epoxy resins.
•The glycidyl epoxies are further classified as
glycidyl-ether, glycidyl-ester and glycidyl-
amine.

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Preparation of Epoxy resin

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Properties of Epoxy resin
•They have excellent resistance to wear, they
are also tough and heat resistant.
•Being polar, they have excellent adhesive
characteristics.
• Low water absorption tendency, dimensional
stability, good heat and electrical resistance

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Applications of Epoxy resin
•Used for surface coating particularly for
making skid resistant surfaces for
highways, road junctions.
•Used as adhesives for glass, metals etc.
and popularly known as araldite.
•It is good material for electronic
applications.