POLYMERS chemistry

1. PRESENTATION ON
POLYMERS
12/6/2016
1

2. CONTENTS
 Polymers
 Classification of polymers
 Types of polymers
 Examples
 Properties
 Applications
 References
12/6/2016
2

3. What are polymers ?
12/6/2016
3

4. The term polymer is derived from two Greek
words : poly means many and mer means
unit or part. They have a high molecular
mass.
So we can say that polymers are high
molecular mass substances each molecule
of which consists of a very large number of
simple repeating structural units joined
together through a covalent bonds in a
regular manner.
12/6/2016
4

5. The simple and reactive molecules from
which the repeating structural units are
derived are called monomers and the
process by which these simple molecules
i.e., monomers are converted into polymers
is called polymerization.
12/6/2016
5

6. CLASSIFICATION OF POLYMERS
12/6/2016
6

7. Homopolymers - consist of chains with identical
bonding linkages to each monomer unit. This usually
implies that the polymer is made from all identical
monomer molecules.
These may be represented as : -[A-A-A-A-A-A]-
Copolymers - consist of chains with two or more
linkages usually implying two or more different
types of monomer units.
These may be represented as : -[A-B-A-B-A-B]-
12/6/2016
7

8. Polymers are further classified by the
reaction mode of polymerization, these
include:
Addition Polymers - the monomer molecules bond to
each other without the loss of any other atoms.
Alkene monomers are the biggest groups of polymers
in this class.
Condensation Polymers - usually two different
monomer combine with the loss of a small molecule,
usually water. Polyesters and polyamides (nylon) are
in this class of polymers.
12/6/2016
8

9. Classification based upon the physical
property related to heating:
Thermoplastics - plastics that soften when heated and
become firm again when cooled. This is the more
popular type of plastic because the heating and cooling
may be repeated.
Thermosets - plastics that soften when heated and can
be molded, but harden permanently. They will
decompose when reheated. An example is Bakelite,
which is used in toasters, handles for pots and pans,
dishes, electrical outlets and billiard balls.
12/6/2016
9

10. Types of polymers
12/6/2016
10

11. Natural polymers - Polymers which are found in
nature are called natural polymer such as
proteins, natural rubber etc.
Semi – synthetic polymers – These are mostly
derived from naturally occurring polymers by
chemical modifications such as vulcanized
rubber etc.
Synthetic polymers – Polymers that are man
made by chemical processes in the laboratories
such as nylon etc. 12/6/2016
11

12. Some examples
12/6/2016
12

13. 12/6/2016
13

14. 12/6/2016
14

15. 12/6/2016
15

16. Properties of Polymers
12/6/2016
16

17. The physical properties of a polymer, such as its
strength and flexibility depend on:
Chain length - in general, the longer the chains the
stronger the polymer;
Side groups - polar side groups give stronger
attraction between polymer chains, making the
polymer stronger;
Branching - straight, un branched chains can pack
together more closely than highly branched chains,
giving polymers that are more crystalline and
therefore stronger;
Cross-linking - if polymer chains are linked together
extensively by covalent bonds, the polymer is harder
and more difficult to melt.
12/6/2016
17

18. Applications of Polymers
12/6/2016
18

19. Surgrical Use
Dextron as it is a biodegradable it is used in stiching
wounds after operation.
Consumer Science
Plastic containers of all shapes and sizes are light
weight and economically less expensive than the
more traditional containers. Clothing, coverings,
garbage disposal bags, and packaging are other
polymer applications.
12/6/2016
19

20. Industry
Automobile parts, windshields for fighter planes,
pipes, tanks, packing materials, insulation, wood
substitutes, adhesives, matrix for composites, and
elastomers are all polymer applications used in the
industrial market.
Sports
Playground equipment, various balls, golf clubs,
swimming pools, and protective helmets are often
produced from polymers.
12/6/2016
20

21. REFERENCES
S . Chand
New course chemistry
Web
12/6/2016
21

22. THANK YOU
12/6/2016
22