Problem 53 - A Complete Resource Book in Chemistry for JEE Main

Question

Which one of the following polymers is prepared by condensation polymerization? (a) Nylon-6, 6 (b) Teflon (c) Rubber (d) Styrene

Step-by-Step Solution

Answer

Nylon-6,6 is prepared by condensation polymerization.

Step 1: Understand Condensation Polymerization

In condensation polymerization, monomers join together, losing small molecules as by-products like water or methanol. This type of polymerization involves the combination of monomers with various functional groups.

Step 2: Analyze Each Option

- Nylon-6,6: Formed through the condensation of hexamethylenediamine and adipic acid, eliminating water. - Teflon: Produced via addition polymerization, not condensation. - Rubber: Typically involves addition polymerization, such as in the production of synthetic rubber. - Styrene: Involves addition polymerization to form polystyrene.

Step 3: Determine Which Polymer Matches Condensation Polymerization

From the analysis, Nylon-6,6 is prepared through condensation polymerization because it involves the elimination of water during the polymer formation.

Key Concepts

Nylon-6,6

Nylon-6,6 is a widely used synthetic polymer known for its strength and durability. It owes its robustness to the type of chemical reaction that forms it, known as condensation polymerization. This process involves the reaction of two monomers: hexamethylenediamine and adipic acid. These monomers react to create long chains of Nylon-6,6, while releasing small molecules like water as by-products.

One of the key features of Nylon-6,6 is its structure. It consists of repeating units of amide bonds, often referred to as peptide links. The presence of these strong chemical bonds gives Nylon-6,6 its high melting point and resistance to wear. It's commonly used in textiles, carpets, and even in the production of engineering plastics.

• Monomers: Hexamethylenediamine and adipic acid
• By-products: Water
• Applications: Textiles, engineering plastics

Polymer Chemistry

Polymer chemistry is the branch of chemistry that focuses on the chemical processes and properties of polymers. Polymers are large molecules made up of repeating structural units or monomers. These monomers can bond together through two primary processes: condensation polymerization and addition polymerization.

In condensation polymerization, monomers with different functional groups join together, and small molecules such as water or alcohol are eliminated. In contrast, addition polymerization involves monomers that have unsaturated bonds (such as double bonds) reacting without the loss of any atoms.

• Two main polymerization types: Condensation and Addition
• Condensation Polymerization: Involves loss of small molecules
• Addition Polymerization: Occurs without by-products

Understanding these processes is vital for grasping how different plastics and synthetic materials are formulated, impacting materials used in everyday life, from packaging to aerospace industries.

Functional Groups

Functional groups play a crucial role in determining the properties and reactions of polymers. In the context of polymer chemistry, they are specific groupings of atoms within molecules that dictate how the molecules behave during chemical reactions.

For instance, in Nylon-6,6, the functional groups are critical to its formation. The monomers used each contain reactive carboxylic acid and amine groups. These groups interact to form amide bonds and release water, a hallmark of condensation polymerization.

Functional groups also influence the physical and chemical properties of the polymer:

• Carboxylic acids: Influence solubility and melting point
• Amines: Determine chemical reactivity and stability
• Amide bonds: Impart strength and resistance

By understanding the role of these groups, students can better predict how polymers will behave and be used in various applications, enhancing their comprehension of polymer chemistry.