Polymers – Definition, Structure, Classification, & Attributes of Polymers

Definition of Polymers

A polymer is a big particle or a macromolecule which essentially is a combination of numerous subunits. The term polymer in Greek means ‘many parts’. Polymers can be found all around us. From the hair of our DNA which is a naturally occurring biopolymer to polypropylene which is utilized throughout the world as plastic.

Polymers may be naturally found in plants and animals (natural polymers) or might be manufactured (synthetic polymers). Various polymers have a variety of distinct physical and chemical properties due to which they have great use in daily life.

The Structure of Polymers

Lots of typical classes of polymers are made up of hydrocarbons, compounds of carbon and hydrogen. These polymers are particularly made of carbon atoms bonded together, one to the next, into long chains that are called the backbone of the polymer. Because of the nature of carbon, several other atoms can be connected to each carbon atom in the chain. There are polymers that contain only carbon and hydrogen atoms.

Polyethylene, polypropylene, polybutylene, polystyrene, and polymethyl pentene are examples of these. Polyvinyl chloride (PVC) has actually chlorine attached to the all-carbon chains. Teflon has actually fluorine attached to the all-carbon backbone.

Other typical made polymers have foundations that consist of aspects aside from carbon. Nylons contain nitrogen atoms in the repeat unit backbone. Polyesters and polycarbonates include oxygen in the backbone. There are also some polymers that, instead of having a carbon chain, have silicon or phosphorous backbone. These are considered inorganic polymers.

Classification of Polymers

Polymers cannot be classified under one category because of their complex structures, various behaviors, and huge applications. We can, therefore, classify polymers based upon the following considerations.

Classification of Polymers based on the Source of Availability

There are 3 kinds under this classification, specifically, Natural, Artificial, and Semi-synthetic Polymers.

Natural Polymers:

They occur naturally and are found in plants and animals. For instance, proteins, starch, cellulose, and rubber. To add more, there also have eco-friendly polymers which are called biopolymers.

Semi-synthetic Polymers:

They are originated from naturally occurring polymers and go through further chemical changes. For instance, cellulose nitrate, cellulose acetate.

Synthetic Polymers:

These are man-made polymers. Plastic is the most common and commonly utilized synthetic polymer. It is used in industries and various dairy products. For example, nylon-6, 6, polyether’s, and so on.

Polymers based upon the Structure of the Monomer Chain

This category has the following classifications:

Linear Polymers

The structure of polymers containing long and straight chains falls under this category. PVC, i.e., polyvinyl chloride is mainly utilized for making pipes and electrical cable televisions is an example of a linear polymer.

Branched-chain Polymers

When straight chains of a polymer form branch, then, such polymers are categorized as branched-chain polymers. For example, Low-density polythene.

Cross-linked Polymers

They are made up of bifunctional and trifunctional monomers. They have a more powerful covalent bond in comparison to other linear polymers. Bakelite and melamine are examples in this category.

Classification Based Upon Polymerization

• Addition Polymerization: Example, poly ethane, Teflon, Polyvinyl chloride (PVC).
• Condensation Polymerization: Example, Nylon -6, 6, perylene, polyesters.

Category Based Upon Monomers

• Homomer: In this type, a single kind of monomer unit is present. For instance, Polyethene.
• Heteropolymer or co-polymer: It consists of different kind of monomer units. For instance, nylon -6, 6.

Category Based Upon Molecular Forces

• Elastomers: These are rubber-like solids weak interaction forces exist. For example, Rubber.
• Fibers: Strong, hard, high tensile strength and strong forces of interaction exist. For example, nylon -6, 6.
• Thermoplastics: These have intermediate forces of destination. For example, polyvinyl chloride.
• Thermosetting polymers: These polymers greatly improve the material’s mechanical properties. It offers enhanced chemical and heat resistance. For instance, phenolics, epoxies, and silicones.

Attributes of Polymers

Every polymer has really unique characteristics, but the majority of polymers have the following general attributes.

1. Polymers can be really resistant to chemicals.
2. Polymers can be both thermal and electrical insulators.
3. Typically, polymers are extremely light in weight with significant degrees of strength.
4. Polymers can be processed in different methods.
5. Polymers are products with a relatively limitless variety of attributes and colors.
6. Polymers are usually made from petroleum, but not always.
7. Polymers can be used to make things that have no alternatives from other products.

Some Polymers and their Monomers

• Polypropene, also called polypropylene, is comprised of monomer propene.
• Polystyrene is an aromatic polymer, naturally transparent, made up of monomer styrene.
• Polyvinyl chloride (PVC) is a plastic polymer made from monomer vinyl chloride.
• The urea-formaldehyde resin is a non-transparent plastic obtained by heating formaldehyde and urea.
• Glyptal is comprised of monomers ethylene glycol and phthalic acid.
• Bakelite or polyoxybenzylmethylenglycolanhydride is a plastic that is made up of monomers phenol and aldehyde.

Frequently Asked Questions

Q1: What is degree of polymerization?

Ans: The number of repeating units that determine the length of polymer is polymerization.

Q2: What is homopolymer?

Ans: Polymer formed by the polymerization of single type of monomer.

Q3: Difference between

Thermoplastic Polymers	Thermosetting Polymers
The polymer becomes soft on heating and hard on cooling with a little change in properties.	The polymer which becomes hard on heating and cannot be softened again is thermosetting polymer.
Formed by addition polymerization.	Formed by condensation polymerization.

 

Q4: What is Terpolymer?

Ans: When three different monomers are polymerized where the polymerization reaction is carefully controlled, the polymer obtained is Terpolymer.