Polymer Reaction Technique

Polymer Reaction Technique

1. 1


Assignment

Course Code : TE-133
Course Title : Polymer Science

Topic :- Polymer Reaction Technique



Submitted To : Taslima Akter
Assistant Professor, Dept of GED,DIU




Submitted By : Md. Toukir Ahmed Srabon
ID-152-23-4325
Section- C1
Dept of TE,DIU




Submission Date:12-04-2020

2. 2

Index

Name Of The Topic Page No
Polymer & Polymerization 04

Monomers 05

Repeat Unit 06

Example Of Polymer , Monomer &
Repeat Unit
07
How Big Are Polymers 08

Classification Of Polymers Depending
On Their Structure
09-10
Types Of Polymer & Polymerizations 11

Addition Polymers 12

Addition Polymerizations 13

Mechanism Of Addition
Polymerization
14
Mechanism Of Polyethylene 15

Conclusion 16
Reference 17

3. 3

Signifiance Of The Study

1. To know about polymer & polymerization.
2. To know about Monomers.
3. To know about repeat unit.
4. Knowledge about example of polymer ,monomer
& repeat unit.
5 .To know about how bigger are the polymer size.
6. To know about the classification of polymer
depending of their structure.
7. To know about types of polymer &
polymerization.
8. To briefly discuss about addition of polymer.
9. To gain about mechanism of addition
polymerization.
10. To gain about mechanism of polyethylene.

4. 4

Description Of The Study

Polymers & Polymerizations:

Polymers are macromolecules built up by the
linking together of large numbers of much smaller
molecules. The process of linking the repeating units
is termed as Polymerization.

5. 5

Monomers



The small molecules which combine with each other
to form polymer molecules are termed monomers.

6. 6

Repeat Unit


A repeat unit or repeating unit is a part of a polymer whose
repetition would produce the complete polymer chain (except for
the end-groups by linking the repeat units together successively
along the chain, like the beads of a necklace.
A repeat unit is sometimes called a mer or unit. "Mer" originates
from the Greek word "meros," which means a part. The word
polymer derives its meaning from this, which means "many mers."
A repeat unit (or mer), is not to be confused with the
term monomer, which refers to the small molecule from which a
polymer is synthesized.
One of the simplest repeat units is that of the addition polymer
polyvinyl chloride, -[CH2-CHCl]n-, whose repeat unit is -[CH2-CHCl]-.
In this case the repeat unit has the same atoms as the
monomer vinyl chloride CH2=CHCl. When the polymer is formed,
the C=C double bond in the monomer is replaced by a C-C single
bond in the polymer repeat unit, which links by two new bonds to
adjoining repeat units.
In condensation polymers (see examples below), the repeat unit
contains fewer atoms than the monomer or monomers from which
it is formed.
The subscript "n" denotes the degree of polymerisation, that is, the
number of units linked together. The molecular mass of the repeat
unit, MR, is simply the sum of the atomic masses of
the atoms within the repeat unit. The molecular mass of the chain is
just the product nMR. Other than monodisperse polymers, there is
normally a molar mass distribution caused by chains of different
length.
In copolymers there are two or more types of repeat unit, which
may be arranged in alternation, or at random, or in other more
complex patterns.

7. 7

Example Of Polymer, Monomer & Repeat Unit:

8. 8

How big are polymers?









Let CH2-
CH2 ≈ 1 inch















This ends up with a chain of approximately 1/4 inch (6.4 mm) in diameter and 1/2 mile (805
m) long.

9. 9

Classification of polymers
depending on their
structure:


Linear polymers:







Branched polymers:

10. 10



Linear polymers & Branched polymer:





Cross-link Polymer:

11. 11

Types of polymers &
polymerizations:

Classification of Polymers:

1.Polymer Structure:

 Condensation Polymer
 Addition Polymer



2.Polymerization Mechanism

 Step Polymerization
 Chain Polymerization


Type of Polymerization:

Monomers undergo polymerizaton by two types. They
are:

 Addition or chain polymerization
 Condensation or step polymerization

12. 12

Addition Polymers



What are addition polymers?

Addition polymers are those formed from monomers without
the loss of a small molecule.







The addition-condensation system:


Condensation polymers:

Polymers whose repeating units are joined together by
functional units such as ester (-OCO-), amide (- NHCO-),
urethane (-OCONH-), sulfide (-SO2-) and other linkages.

-R-Z-R-Z-R-Z-R-Z-R-Z-

R is aliphatic or aromatic grouping and Z is functional unit.

The major addition polymers are those formed by polymerization of
monomers containing carbon-carbon double bond; such monomers
are called vinyl monomers or substituted ethylenes.

13. 13

Addition polymerization



Self addition of several bifunctional monomers to each
ohter takes place by chain reaction without the elimination of
any simple molecules.

GENERAL REACTION:

n [CH2=CH] - [-CH2-CH-]n

_
Addition polymerization is initiated by small qty of
substance called Initiators.
–
E.g.-Zeigler-Natta catalyst, potassium persulphate ,
dibenzoyl sulphat e.




Condensation polymerization

Self addition of several bifunctional monomer to each other
takes place accompanying elimination of simple molecules
like H2O,NH3 & HCL

E.g..
 Terylene is obtained by condensing terpthalic acid
[HOOC-C6H4-COOH] with ethylene glycol [HO-
C2H4-OH]
 Nylon is made by the condensation of adipic acid
[HOOC-(CH2)4-COOH] with hexamethylene diamine
[NH2-(CH2)6-NH2]

14. 14

MECHANISM OF ADDITION
POLYMERIZATION :

FREE RADICLE REACTION MECHANISM


 Free Radical Mechanism of chain reaction involves 3 stages namely

1. Initiation
2. Propagation
3. Termination

 SCHEMATIC REPRESENTATION

[ R* - Free radical
M* - Unsaturated Monomer]


Generation of free radical :

I > 2R E.g. <> CH2=CH2


Initiation :

R+ M <> RM1

Propagation :

RM1+ M <> RM2
RM2+ M <> RM3

RM( x – 1 )+ M <> RM x
RM( y – 1 )+ M <> RM y

Termination :

RM x + RM y <> RM x + y (COUPLING)
RM x + RM y <> RM x + RM y

15. 15

Mechanism Of Addition
Polymerization Of Polyethylene:

Synthesis of poly-ethylene -(CH2-CH2)- n from Ethylene, CH2=CH2 using di-benzoyl
peroxide(C6H5COO)2 as the indicator

n CH2=CH2 <> -(CH2-CH2)- n
(C6H5COO)2


Termination

By coupling (by the combination of two radicals)


R-(CH2-CH2)X-CH2-CH2 + CH2-CH2-(CH2-CH2)Y-R


R-(CH2-CH2)X-CH2-CH2-CH2-CH2-(CH2-CH2)Y-R



By disproportionation

R-(CH2-CH2)X-CH2-CH2 + R-(CH2-CH2)Y-CH2-CH2



R(CH2CH2)X-CH2-CH3 + R(CH2CH2)Y-CH=CH2

16. 16

Conclusion:

By doing this assignment I gained a lot
knowledge about polymer reaction technique .Beside
that I also know about the polymerization ,repeating
unit ,monomer ,addition polymer and addition
polymerization ,mechanism of polymer and
polymerization and many others things .These
things will help me in future a lot.

17. 17

References:



Taslima Akter
Assistant Professor, Dept of GED,DIU
www.textiletoday.com.bd
www.danti.it
www.textileschool.com
www.encyclopedia.com








THE END