Polymers, Ideal properties, Classification/Types, Applications

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

2. Contents Introduction Ideal Properties Classification Applications References

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

6. C lassification

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

11. Applications

12. 1. Medicine: Many biomaterials especially heart valve replacements and blood vessels are made-up of polymers like T eflon, 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. R eferences Robinson J R and Lee V .H, Controlled drug delivery –fundamentals and applications, M arcel Dekker Jain N k, Controlled and Novel Drug Delivery; CBS Publication

14. THANK-YOU