Explain the classification of polymers with suitable examples.
Answers
Answer:
Polymers cannot be classified under one category because of their complex structures, different behaviours and vast applications. We can, therefore, classify polymers based on the following considerations.
Explanation:
Classification of Polymers based on the Source of Availability
There are three types of classification under this category, namely, Natural, Synthetic, and Semi-synthetic Polymers.
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 which are called biopolymers.
Semi-synthetic Polymers:
They are derived from naturally occurring polymers and undergo further chemical modification. For example, cellulose nitrate, cellulose acetate.
Synthetic Polymers:
These are man-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’s etc.
Classification of Polymers based on the Structure of the Monomer Chain
This category has the following classifications:
Linear Polymers
The structure of polymers containing long and straight chains fall into this category. PVC, i.e. poly-vinyl chloride is largely used for making pipes and electric cables is an example of a linear polymer.
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.
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 in this category.
Other Ways to Classify Polymers
Classification Based on Polymerization
Addition Polymerization: Example, poly ethane, Teflon, Polyvinyl chloride (PVC)
Condensation Polymerization: Example, Nylon -6, 6, perylene, polyesters.
Classification Based on Monomers
Homomer: In this type, a single type of monomer unit is present. For example, Polyethene
Heteropolymer or co-polymer: It consists of different type of monomer units. For example, nylon -6, 6
Classification Based on Molecular Forces
Elastomers: These are rubber-like solids weak interaction forces are present. For example, Rubber.
Fibres: Strong, tough, high tensile strength and strong forces of interaction are present. For example, nylon -6, 6.
Thermoplastics: These have intermediate forces of attraction. For example, polyvinyl chloride.
Thermosetting polymers: These polymers greatly improve the material’s mechanical properties. It provides enhanced chemical and heat resistance. For example, phenolics, epoxies, and silicones