Introduction

Repetitive units of at least two distinct monomers form the copolymer. Some examples of these copolymers are block copolymers, alternative copolymers, and graft copolymers. The monomer chains in random copolymers are randomly distributed; in alternative copolymers, they are in an ordered form, in block copolymers, they are at the ends of the chain, and in graft copolymers, they are at different positions on the host polymer.

Polymer 

What are Copolymers?

A copolymer consists of 2 or more different monomer units chained together to produce a polymer. Keep in mind that copolymers are a kind of polymer. When numerous smaller molecules, called monomers, are joined together, the resulting molecule is called a polymer. The distinctive repeating subunits found only in copolymers set them apart from all other types of materials.

Classification of Copolymers

There are three major types of copolymers.

1. Block polymer: The earliest type of polymers are block polymers. A polymer is the result of the joining of two or more long chains. Each chain consists of a different collection of monomer subunits, with just one kind used in the first chain. One way to think about this copolymer is as the result of the combination of two distinct homopolymers. The prefix homo- means "same" or "similar." This means that the building blocks of a homopolymer are the same or very similar. You may picture yourself with a block polymer in your left hand and a block polymer with a homopolymer chain in your right. When you mix the two together, you get a block copolymer.

2. Random copolymer: The second type of copolymer is a random copolymer. A random copolymer is formed when monomer subunits are linked together in a haphazard method. Imagine you have a handful of monomers, and you fling them in the air, only to catch them as they fall to the earth. If you were to join those monomers together wherever they landed, you'd get a completely different random chain every time.

3. Alternate copolymer: Finally, there's a third variety called alternative copolymers. Alternate copolymers are polymers made up of monomers that link together in alternating fashion. Let's have a look at the molecular structure of this copolymer to get a better grasp on what it is.

What are the Different Types of Linear Copolymers?

This classification is made according to the arrangement of the monomers on the main chain:

1. Block Copolymers: Single-chain macromolecules called block copolymers result from the covalent bonding of several homopolymer units. To connect two separate homopolymer chains, a junction block is used. In contrast to a diblock copolymer, which only includes two homopolymer units, a triblock copolymer has three. One example of such a polymer is acrylonitrile butadiene styrene or SBS rubber. 

2. Statistical Copolymer: Statistical copolymers are a kind of polymers characterised by the presence of two or more monomers ordered in accordance with a statistical rule. If the probability of encountering a residue of a given monomer anywhere along the chain is proportional to its mole fraction, we call the entire polymer a random polymer. 

3. Alternating Copolymers: The formula for an alternating copolymer composed of monomers A and B may be extended to (-A-B-)n. Alternating copolymers have only one chain with alternating monomers. Hexamethylenediamine, as well as adipic acid, are alternately arranged in Nylon 6,6 as an instance of an alternating copolymer.

4. Periodic Copolymers: The monomers in these polymers are organised in a single chain and have a recurring sequence. For instance, periodic copolymers are copolymers with recurring sequences of their structural units. The abbreviation for periodic copolymers is (ABC)n if structural units are denoted by capital letters. In this notation, ABC stands for the period and n⋲N (n2)  for the number of repeats of the period that make up the periodic copolymer. 

5. Gradient and Stereoblock Copolymers: Single-chain copolymers with varying monomer contents throughout the main chain are called "gradient copolymers." Both forced gradients and compositional gradients that arise spontaneously during copolymerisation can be used to synthesise gradient copolymers. Spontaneous gradient copolymers, which rely on differences in the reactivity ratios of the two monomeric species, are produced by the batch approach. Controlled free radical polymerisation can spontaneously form monomer pairs, such as styrene and acrylic acid, n-butyl acrylate and n-butyl methacrylate, etc.

Summary

A copolymer, then, is a polymer that results from the polymerisation of many types of monomers. This process of polymerization, known as copolymerization, has a specific name. There is a wide variety of copolymers and methods of polymerisation that may be used to create them. When two different types of monomers combine, the resulting copolymer is called a bipolymer. Copolymers are formed when many monomeric units or species are covalently bound together in a straight or branched chain. Several different types of businesses make use of copolymers. A wide variety of applications may be found for nylon 6.6, High strength polystyrene, SBS rubber, etc. This wide range of uses is possible because copolymers have drastically altered chemical properties that make them valuable.

 Frequently Asked Questions 

1. Buna-S makes up which polymer?

Buna- S monomer polymerises to form rubber. The monomer itself comprises butadiene, sodium and styrene. This is used majorly as a source of rubber and rubber-like materials and applied in the tyre industry, conveyor belts, etc. 

2. How is condensation reaction important in polymers?

The condensation process produces Condensation polymerisation, also known as step-by-step growth polymerisation, which happens during any type of copolymerization (bi-functional / tri-functional) between two separate monomeric species. The removal of impurities like water, ammonia, and alcohol from a final product is the result of a series of condensation processes.

3. Is nylon-6,6  a copolymer?

Yes, nylon-6,6 is a copolymer. Nylon 66 gets its name because it is composed of two monomers, hexa methylenediamine and adipic acid, that each contains 6 carbon atoms. Polyamides, or nylons, include Nylon 66. It is second only to nylon 6 in prevalence in the textile and plastics sectors.