POLYMERS
Introduction:
It is synonym for Plastic.
Also known as Macromolecules.
The word ‘polymer’ comes from Greek words: polymeros
Poly means ‘many’ and ‘mer’ means ‘parts’.
These are very large molecules consisting of many repeating units called monomers [small molecules] and are formed by a process called polymerization.
In other words, polymers are very large molecules made when 100’s of monomers join together to form long chains.
Ideal Properties:
1. It should be inert.
2. It should be non-toxic.
3. It should be compatible with environment.
4. It should be easy to fabricate and inexpensive.
5. It should be biodegradable and biocompatible.
6. It should provide good drug polymer linkage.
Classification of Polymers
1. Based on the Source of Availability
There are three types of classification under this category, namely, natural, synthetic, and semi-synthetic polymers.
a. Natural Polymers
They occur naturally and are found in plants and animals. For example, proteins, starch, cellulose and rubber. To add up, we also have biodegradable polymers called biopolymers.
b. Semi-synthetic Polymers
They are derived from naturally occurring polymers and undergo further chemical modification. For example, cellulose nitrate and cellulose acetate.
c. Synthetic Polymers
These are human-made polymers. Plastic is the most common and widely used synthetic polymer. It is used in industries and various dairy products. For example, nylon-6, 6, polyether, etc.
2. Based on the Structure of the Monomer Chain:
a. Linear Polymers
The structure of polymers containing long and straight chains falls into this category. PVC, i.e., polyvinyl chloride, is largely used for making pipes, and an electric cable is an example of a linear polymer.
b. Branched-chain Polymers
When linear chains of a polymer form branches, then such polymers are categorized as branched chain polymers. For example, low-density polythene.
c. Cross-linked Polymers
They are composed of bifunctional and trifunctional monomers. They have a stronger covalent bond in comparison to other linear polymers. Bakelite and melamine are examples of cross-linked polymers.
3. Classification Based on Polymerization
a. Addition Polymerization: For example, poly ethane, Teflon, polyvinyl chloride (PVC), etc.
b. Condensation Polymerization: Eg include nylon -6, 6, perylene, polyesters, etc.
4.Classification Based on Monomers
a. Homomer: In this type, a single type of monomer unit is present. Eg, polyethene.
b. Heteropolymer or co-polymer: It consists of different types of monomer units. Eg, nylon -6, 6.
5.Classification Based on Molecular Forces
a. Elastomers: These are rubber-like solids, and weak interaction forces are present in them. Eg, rubber.
b. Thermoplastics: These have intermediate forces of attraction. eg polyvinyl chloride.
c. Thermosetting polymers: These polymers greatly improve the material’s mechanical properties. It provides enhanced chemical and heat resistance. Eg silicones, phenolics.
1. POLYMERS
Presented by:
Miss. Kamble Akanksha M.
Roll No: 03 [DDS]
First Year M-Pharmacy
Dept. of Pharmaceutics
S.M.B.T.C.O.P, Igatpuri.
SEMINAR PRESENTATION
3. Introduction
POLYMERS
• It is synonym for Plastic.
• Also known as Macromolecules.
• The word ‘polymer’ comes from Greek words: polymeros
• Poly means ‘many’ and ‘mer’ means ‘parts’.
4. • These are very large molecules consisting of many repeating units
called monomers [small molecules] and are formed by a process
called polymerization.
• In other words, polymers are very large molecules made when 100’s
of monomers join together to form long chains.
5. Ideal Characteristics
It should be inert.
It should be non-toxic.
It should be compatible with environment.
It should be easy to fabricate and inexpensive.
It should be biodegradable and biocompatible.
It should provide good drug polymer linkage.
7. I. Based on source:
Sr. No. Type of Polymer Description Examples
1. Natural
Polymers which are isolated
from natural materials.
Cellulose, Wool
2. Semi-synthetic
Derived from nature itself
but undergo chemical
processes.
Rayon
3. Synthetic
Polymers made from
chemical reactions.
Polyester,
Polyethylene
8. Sr. No. Type of Polymer Description Examples
1. Linear
Monomers linked linearly to
each other
PE, PVC
2. Branched-chain
Monomers linked like a
branches
Low-density
polyethylene [LDPE]
3. Cross-linked
Monomers are connected to
each other.
Bakelite
II. Based on structure:
9. III. Based on mode of Polymerization:
Sr. No. Type of Polymer Description Examples
1. Homo-Polymer
It is made-up single type of
monomer. Identical bonding
linkages to each monomer
unit.
Polypropene,
Polyethene
2. Co-polymer
When two or more different
monomers together
[different repeating units]
Buna-S
10. IV. Based on molecular forces:
Sr. No. Type of Polymer Description Examples
1. Elastomers
They deform under force but
will return to original shape
once the stress is released.
2. Thermo-setting
A type of plastic that gets
permanently hard after
heating.
Unsaturated
Polyester Resins
3. Thermo-plastic
A type of a plastic that can
be softened by heat and
hardened by cooling.
PE, Nylon, PVC
12. 1. Medicine:
Many biomaterials especially heart valve replacements and blood vessels are
made-up of polymers like Teflon, Dacron
2. Consumer Science:
Plastic consumers of all shapes and sizes are light weight and economically
less expensive than more traditional containers.
3. Industry:
Automobile parts, pipes, tanks, packing material, adhesives are all polymer
application used in the industrial market.
4. Sports:
Playground equipment, golf clubs, swimming pools and protective helmets
are produced from polymers.
Applications
13. References
1. Robinson J R and Lee V .H, Controlled drug delivery –fundamentals and
applications, Marcel Dekker
2. Jain N k, Controlled and Novel Drug Delivery; CBS Publication