Edited By Team Careers360 | Updated on Dec 20, 2024 05:52 PM IST
Polymer is a term composed of two words i.e poly which means many and mer which means unit. Thus polymer is a bigger molecule made up of various smaller molecules, therefore polymers are also known as macromolecules. Some examples of polymers or macromolecules are polyethene, DNA, protein, Nylon 6,6, etc. The process of formation of polymers by joining the structural units is known as polymerisation. In this article, we have discussed various types of polymers that are always around us and play a vital role in our life.
Polymers - Types, Classification, Properties, and Uses
Polymers are macromolecules formed by the repeated linkage of smaller units called monomers. They can be classified based on origin (natural, synthetic), structure (linear, branched, cross-linked), and polymerization mechanism (addition, condensation). Natural polymers like cellulose and synthetic polymers like PVC have diverse applications. Polymers possess unique properties such as flexibility, durability, and resistance to water and chemicals. They are widely used in industries, including textiles, packaging, construction, and electronics.
Natural Rubber and Synthetic Rubber
Natural rubber is primarily composed of polyisoprene and is obtained from latex. Its elasticity and water resistance make it versatile, but vulcanization with sulfur is required to enhance its strength and durability. Synthetic rubber like neoprene and SBR (styrene-butadiene rubber), is made from petroleum-based monomers. Synthetic rubber exhibits improved resistance to heat, chemicals, and wear. Both Natural rubber and Synthetic rubber are important for manufacturing tires, footwear, and industrial goods.
Polyester
Polyesters are synthetic polymers formed through condensation polymerization of diols and dicarboxylic acids. The most common example is polyethylene terephthalate (PET). Polyesters are known for their durability, lightweight nature, and resistance to environmental conditions. Their properties make them suitable for applications in textiles, packaging materials (bottles), and insulation films.
Biodegradable polymers are environmentally friendly materials that decompose under the action of microorganisms. Examples include polylactic acid (PLA) and polyhydroxybutyrate (PHB). These polymers are increasingly used in applications where environmental sustainability is crucial, such as agriculture, packaging, and medical devices. Their ability to minimize plastic waste has made them significant in addressing global pollution challenges.
Overview of the chapter
In this chapter, you will study the various types of polymers that we use in daily life. In the following section, the classification of polymers is done using different methods.
Classification of polymers
Polymers are classified on the basis of various categories as given below:
(i) Classification of polymers on the basis of source: In this category, polymers are classified on the basis of source of origin:
Natural Polymers: These are the polymers that are directly obtained from nature. For example, protein, starch, rubber, etc.
Semi-synthetic Polymers: These are those polymers that are prepared in the laboratory by making some modifications in the natural polymers. For example, cellulose nitrate, cellulose acetate, etc.
Synthetic Polymers: These are completely man-made polymers and developed in the laboratory. Some common examples are plastic, nylon 6,6, etc.
(ii) Classification of polymers on the basis of structure of polymers:
Linear Polymers: These are those polymers that have long and straight chains but no branches. Some common examples include high density polythene, polyvinyl chloride, etc.
Branched-chain polymers: These are those polymers that have long chains but also have some branches. Some examples include low-density polythene.
Cross-linked or Network polymers: These are the polymers that have a long straight chain but these chains are connected through the strong covalent bonds. Examples are bakelite, melamine, etc.
(iii) Classification of polymers on the basis of mode of polymerization:
Addition polymers: These are those polymers that are formed by the repeated addition of monomer. The addition polymers are of two types viz: (i) Homopolymers: These are the polymers that are formed by the addition of the same monomers. For example:
(ii) Copolymers: The polymers formed by the addition of different monomers are known as copolymers. For example Buna-S, Buna-N, etc.
Condensation polymers: These are those polymers that are formed by the repeated condensation reaction of two different bi-functional or tri-functional monomeric molecules. In these reactions, small molecules such as water, hydrogen chloride, etc eliminate. Some common examples include nylon 6,6, terylene, etc.
(iv) Classification of polymers on the basis of molecular forces:
Elastomers: These are those types of polymers in which the polymer chains are weakly bound to each other. Because of this weak interaction, these polymers have the elastic property. Some crosslinks are also present between the chains due to which these polymers are able to regain their original position. Some examples include buna-S, buna-N, etc.
Fibers: These are thread forming polymers. These polymers have high tensile strength and high modulus. They have strong intermolecular forces and thus have crystalline nature. Some examples include polyamides, polyesters, etc.
Thermoplastic polymers: These polymers have a long chain of molecules with some branches. These molecules have the property to be softening on heating and hardening on cooling. Their intermolecular forces of attraction are intermediate between elastomers and fibres. Some common examples include polythene, polystyrene, etc.
Thermosetting polymers: These are highly branched chain polymers. These polymers cannot be reused. Some common examples include bakelite, urea-formaldehyde resins, etc.
Types of polymerization reactions
There are basically two types of polymerization reactions that you have to study in this chapter.
Addition polymerization or chain-growth polymerization: In this type of polymerization reaction, the addition of the same or different type of monomers occurs. These monomers are unsaturated in nature and their addition leads to the long-chain polymers. Examples include high-density polyethylene, Teflon, etc.
Condensation polymerization or step-growth polymerization: In this type of polymerization reaction, the repetitive condensation reaction of two bi-functional monomers takes place. This polymerization reaction results in the elimination of small molecules like water, alcohol, etc. Some examples include nylon 6,6, terylene, etc.
The Molecular Mass of Polymers
The molecular mass of polymers differs in different samples. The size and mass of any polymer depend on the number of monomers present in the reaction mixture. The properties of polymers depend upon their size and mass. Thus the molecular mass of any polymer is always measured in terms of average.
Biodegradable polymers
Most of the polymers available to us are non-biodegradable. Thus it has been a major environmental issue to degrade these non-biodegradable polymers. These polymers take a very long time to degrade and thus create so many problems to the environment. To eliminate all these problems, some new biodegradable polymers have been developed as mentioned below:
Other than the polymers that have been described, there are further many more other polymers that commercial importance. These are described in the table below along with their uses.
Name of Polymer
Monomer
Uses
Polypropene
Propene
Manufacture of ropes, toys
Polystyrene
Styrene
wrapping material, manufacture of toys
PVC
Vinyl chloride
Manufacture of raincoats, handbags, water pipes
Urea-formaldehyde resin
Urea and formaldehyde
Manufacture of unbreakable cups
Glyptal
Ethylene glycol and Phthalic acid
Manufacture of paints and lacquers
Bakelite
Phenol and formaldehyde
For making combs, electrical switches
How to prepare for Polymers?
This chapter is part of organic chemistry. It is completely theory-based. You are not supposed to memorize any formula and numerical practice for getting the good hold on this chapter.
In this chapter, you need to remember the names of some important polymers and you also need to take care of the classification section
This chapter is not very lengthy, it is easy and remembering the diagrams of polymers is not necessary.
Prescribed Books
For this chapter, first, the NCERT book is best for initial level preparation as well as for board exams. Now, after this, if you want to prepare for competitive exams like JEE and NEET, then these are the best books for you - Morrison and Boyd and R.K Gupta by Arihant publication. Meanwhile, in the preparation, you must continuously give the mock tests for the depth of knowledge. Our platform will help you to provide with the variety of questions for deeper knowledge with the help of videos, articles and mock tests.
Polymers are large molecules made of repeating structural units called monomers. They can be classified based on origin (natural or synthetic), structure (linear, branched, cross-linked), or polymerization mechanism (addition or condensation).
2.What is the difference between natural and synthetic rubber?
Natural rubber is derived from the latex of rubber trees and consists of polyisoprene. Synthetic rubber is made from petroleum-based monomers, offering enhanced resistance to heat, chemicals, and wear. Examples of synthetic rubber include neoprene and SBR (styrene-butadiene rubber).
3.What are polyesters, and where are they used?
Polyesters, such as PET (polyethylene terephthalate), are synthetic polymers formed by the reaction of diols and dicarboxylic acids. They are widely used in textiles, packaging materials, and insulation films due to their durability and lightweight properties.
4.Why are biodegradable polymers important?
Biodegradable polymers decompose naturally by microorganisms, reducing plastic waste and environmental pollution. Examples include polylactic acid (PLA) and polyhydroxybutyrate (PHB). They are used in eco-friendly packaging, agriculture, and medical applications.
5.What are some examples of natural polymers?
Natural polymers include cellulose, proteins, starch, and natural rubber. They occur naturally and are used in various applications like paper, textiles, and food products.
6.Are all polymers environmentally harmful?
Not all polymers are harmful. Biodegradable polymers, such as PLA and PHB, are designed to decompose naturally and are considered eco-friendly alternatives to traditional plastics.
Solution : The correcrt option is 4 i.e "Only 1, 2, and 4." Explanation:
Let's refer to the following lines of the passage:
The device has a very simple structure consisting of specially designed nanocomposite polymers and contact electrodes and can generate a few Milliwatt (Mw) power, which is sufficient to power small electronic devices like watches, digital thermometers, radio frequency transmitters, healthcare sensors, pedometers.
The above statement clearly mention the watches, pedometers and radio frequency transmitters.
