Question

Define the term polymerisation.

Short answer

Polymerization is the chemical process that combines monomers to form a polymer.

Step-by-step solution

Understand Polymer Basics

Polymers are large molecules composed of repeating structural units called monomers. These monomers are small molecules that can join together chemically to form larger structures. Understanding these basic building blocks is crucial for defining polymerization.

Introduction to Polymerization

Polymerization is the process through which monomers combine to form a polymer. This process involves chemical reactions that link monomer residues together, transforming them into complex, chain-like structures. Polymerization can create different types of polymers with various properties depending on the monomers and conditions used.

Types of Polymerization

There are two primary types of polymerization: addition polymerization and condensation polymerization. Addition polymerization occurs when monomers add together without the loss of any atoms, while condensation polymerization involves monomers combining with the loss of small molecules, such as water.

Importance of Polymerization

Polymerization is essential in creating a wide range of materials with diverse properties, from synthetic rubber to plastics and fibers. These materials play a vital role in everyday products and industrial applications. Understanding polymerization helps in designing specific materials with desired characteristics.

Key concepts

Monomers

Monomers are the building blocks of polymers. These small, often simple molecules have the ability to bind chemically with others like themselves. This is due to their specific reactive sites, which allow them to connect and form larger chains or structures.
In other words, if you think of a polymer as a train, then monomers are the individual train cars. Each monomer has a distinct structure that influences the properties of the resulting polymer. For example:

• Ethene is a monomer that can form polyethylene, a common plastic.
• Amino acids are monomers that link together to create proteins.

Understanding monomers is fundamental to comprehending how polymers are synthesized and how their properties can be tailored for specific uses.

Addition Polymerization

Addition polymerization is a fascinating process where monomers join without losing any atoms. This means the entire monomer structure is incorporated into the growing polymer chain.
In this method, each monomer has a double bond, which opens up to link with another monomer. This sequential linkage forms long chains until the supply of monomers runs out or the process is halted. Here are some key aspects:

• No by-products are produced, making the reaction clean.
• Commonly occurs with monomers like ethene or propene resulting in well-known plastics, such as polyethene and polypropylene.

Addition polymerization allows for the creation of polymers with consistent structures and predictable properties, which are significant in manufacturing durable and reliable materials.

Condensation Polymerization

Unlike addition polymerization, condensation polymerization involves monomers bonding together and releasing small molecules, such as water or methanol. This process usually requires two different monomers with complementary reactive groups.
During the reaction:

• Each union of monomers results in the loss of a small molecule, often leading to the formation of by-products.
• Examples of polymers formed this way include nylon and polyester, which are crucial in the textiles industry.

The characteristic release of molecules during the reaction allows for a diversity of polymers with varied molecular structures and properties. This type of polymerization is vital for creating materials with specific characteristics like flexibility, strength, and resistance to environmental factors.