development of diagnostic enzyme assay to detect leuser virus
polymers.pptx
1. The word ‘polymer’ comes from the Greek words poly
(meaning ‘many’) and meros (meaning ‘parts’).
Polymers are very large molecules made when hundreds of
monomers join together to form long chains.
Plastics are synthetic polymers that can be
shaped by heat or pressure.
What are polymers?
2. INTRODUCTION
• In 1845 the first semisynthetic polymer made
of gun cotton (cellulose nitrate) by Christian F
schonbein
• In 1872 Backelite a strong and durable
synthetic polymer based on phenol and
formaldehyde was invented
• In 1933 polyethylene, 1935 polyamide, 1938
Teflon, 1942 synthetic rubber was invented
3. A polymer is a very large molecule in which one or two
small units is repeated over and over again
The small repeating units are known as monomers
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-A-A-A-A-A-A-
A
A polymer is a very large molecule in which one or two small
units is repeated over and over again
The small repeating units are known as monomers
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-A-A-A-A-A-
A-
4. Chemical Structure
• Homopolymer – only one monomer
(repeating unit)
- A – A – A – A – A – A – A -
• Copolymer – more than one monomer
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7. In another kind of polymer, two different monomers
might be involved
If the letters A and B represent those monomers, then the
polymer could be represented as:
-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A
A polymer with two different monomers is known as a
copolymer.
In another kind of polymer, two different monomers might
be involved
If the letters A and B represent those monomers, then the
polymer could be represented as:
-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-
A-B-A
A polymer with two different monomers is known as a
copolymer.
9. Copolymers
• Alternating
- A – B – A – B – A – B – A – B -
- A – A – B – B – A – A – B – B –
• Block
-A-A-A-A-A-B-B-B-B-B-A-A-A-A-A-
-A-A-A-A-A-A-A-B-B-B-B-B-B-B-
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13. Based on chemical nature
• Organic polymers – whose backbone chain is
made of carbon atoms
• Eg; cellulose, proteins
• Inorganic polymers – no carbon atom in the
back bone eg; glass, silicone, rubber
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25. Addition or Chain Polymerization-
• The word chain indicates elongation of carbon skeleton to form
a polymer.
Generally such a polymerization involves the (C = C) link in
monomer. The double bond breaks and as a result two single
bonds on either side of each carbon are formed and thereby
elongation of carbon chain continues. The product of this type
of polymerization is exact multiple of monomer number, having
no by-product or loss of any molecule. Thus,
• a. Addition polymerization is undergone by monomers having
C = C linkage,
e.g. ethylene, vinyl chloride, propylene, butadiene, styrene etc.
• b. The rate of reaction is very high.
• c. The polymerization reaction involves three steps such as
• a) Initiation b) Propagation or branching and c) Termination.
26. • Initiation: free radical catalyst react with a double
bond carbon monomer, beginning of the polymer
chain (peroxides and certain azo compounds)
• Propagation: It is a repetitive operation the double
bond of successive monomers is opened up
• Termination : occurs when another free radical from
(R-O*) left over meets the end of the growing chain.
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28. Thus,
• a. Condensation polymerization is
undergone by the monomers which possess
functional groups.
• b. Generally monomers like acids, amines,
alcohols, phenols, carbonyl compounds etc.
• c. This type of polymerization occurs
stepwise, hence the rate of polymerization is
comparatively slow, it depends on kind of
catalyst , temperature and the time of reaction
• Ex: Nylon 66 Phenol formaldehyde
29. iii) copolymerization:
• It is a joint polymerization of two or more different
monomers. High molecular weight compounds obtained
by copolymerization are called copolymers. For example
1,3-butadiene and styrene copolymerizes to give Buna-S
•To modify the properties of manufactured plastics to
meet specified needs.
