POLYMERS IN PHARMACY

                       POLYMER

                       What are Polymers?

Polymers are very large molecules made when hundreds of monomers join together to form long chain.

The word “polymer” comes from the Greek words poly means Many and meros means parts.

EXAMPLES : Polyetheylene

(ethylene + ethylene + …… )n

Where, n = 4000.   

              

1. Classification of Polymers based on the Source of Availability.

•Natural Polymers :These polymers occur naturally in nature and are found in plants and animals. Additionally, there are also biodegradable polymers called bipolymers. Examples included starch, proteins, rubber, and cellulose.

 2.Semi-Synthetic Polymers : These polymers are developed from natural polymers and are chemically modified. For example, cellulose acetate, cellulose nitrate, etc.

3. Synthetic Polymers:These polymers are completely man-made. Plastic as we use commonly is the most broadly used synthetic polymer. Synthetic polymers are used in industries and several dairy products. Examples include polyether, nylon-6, 6, 6, etc.

 

2.Classification of Polymers based on its Structure

•Linear Polymers : Linear polymers are structured such that they have long and straight chains. For example, Polyvinylchloride (PVC) is used in electric cables and pipes.

•Branched-chain Polymers: Branched-chain polymers are those where linear chains form branches. An example is a low-density polythene.

 Cross-linked Polymers :Cross-linked polymers have bifunctional and trifunctional monomers. As compared to linear polymers, these a stronger covalent bond. Examples include melamine and bakelite.

3.Classification of Polymers based on Polymerization.

•Addition Polymerization: In Addition Polymerization, molecules of the same or different monomers add up together on massive scales to form polymers. These monomers are unsaturated compounds like alkenes, alkadienes, and their respective derivatives.

For example, Teflon, Polyvinyl chloride (PVC), poly ethane, etc are addition polymerization.

•Condensation Polymerization: In Condensation Polymerization, there is a repetition of a condensation reaction between two bi-functional or tri-functional monomeric units.

• For example, perylene, polyesters, Nylon -6, 6, etc are condensation polymers.

 

4.Classification Based on Molecular Forces

•Elastomers:Elastomers have weak interaction forces. Examples are rubber and Buna-S.

Fibers:Fibers have tough, strong, and high tensile strength and very strong forces of interaction. An example is Nylon -6, 6.

•Thermoplastics: The type of plastic that can be softened multiple time on heating and this plastic can be molded into different shape. It can be easily recycle.

Example : carrier bags , detergent bottle Plastic chair.

•Thermosetting polymer : Once heated and formed to a shape, cannot be reheated and reformed. So they difficult to recycle. 

example: epoxyresin is used drums and tools and polyester resin is used electical part.