Problem 116 - A Complete Resource Book in Chemistry for JEE Main

Question

Which of the following is a polyamide? (a) Teflon (b) Nylon-6, 6 (c) Terylene (d) Bakelite

Step-by-Step Solution

Answer

(b) Nylon-6, 6 is a polyamide.

Step 1: Understanding Polyamide

Polyamides are a class of polymers that contain recurring amide groups (-CONH-) as an integral part of the main polymer chain. We need to identify which option involves such a structure.

Step 2: Analyze Option (a) Teflon

Teflon is the trade name for polytetrafluoroethylene (PTFE), which is a polymer of tetrafluoroethylene. It does not contain amide groups; instead, it consists of carbon and fluorine atoms only.

Step 3: Analyze Option (b) Nylon-6, 6

Nylon-6, 6 is a type of synthetic polymer that is well-known for its amide linkages in the backbone. It is created by polycondensation of hexamethylenediamine with adipic acid, forming polyamide bonds.

Step 4: Analyze Option (c) Terylene

Terylene is a polyester made from the polymerization of ethylene glycol and terephthalic acid. It has ester linkages, not amide linkages, in its structure.

Step 5: Analyze Option (d) Bakelite

Bakelite is a phenol-formaldehyde resin and does not contain amide linkages. It is a thermosetting polymer made through condensation of phenol and formaldehyde.

Step 6: Conclusion

Based on the analysis of options, Nylon-6, 6 is the only option that contains the amide linkages characteristic of polyamides.

Key Concepts

Amide Linkages

Amide linkages are the key connections that form the backbone of polyamides, a class of polymers. These linkages are recognized by the presence of the functional group (-CONH-). In chemical terms, an amide linkage is a bond between the carbon atom in a carboxylic acid group and the nitrogen atom in an amine group.

This specific bond is created during a reaction known as condensation polymerization, where water is a byproduct. Amide linkages are vital because they significantly contribute to the strength and stability of polyamide materials.

When these bonds form, the result is a long chain known as a polymer. These chains can vary in length and composition depending on the specific types of acid and amine used. Common examples featuring amide linkages include both natural proteins and various synthetic materials such as nylon.

Understanding amide linkages is crucial in polymer chemistry, as it helps to identify and engineer materials with specific properties.

Nylon-6,6

Nylon-6,6 is a fascinating and widely used example of a synthetic polyamide. It is characterized by the presence of amide linkages, furnishing it with remarkable durability and strength.

This polymer is synthesized through a polycondensation reaction between hexamethylenediamine and adipic acid. During this process, these molecules connect through their amine and acid groups, forming amide linkages and releasing water molecules as a byproduct.

• Nylon-6,6 is used in a wide array of applications due to its excellent mechanical properties.
• It serves as a material for textiles in clothing, as it's known for being resistant to wear and tear.
• It is also employed in industrial uses, such as in the creation of ropes, automotive components, and engineering plastics.

Skills in synthesizing and manipulating materials like Nylon-6,6 are invaluable in material science, allowing for the creation of innovative solutions to modern challenges.

Synthetic Polymers

Synthetic polymers are human-made chains of repeating molecular units known as monomers. These polymers encompass a wide range of materials, including plastics, rubbers, and fibers, many of which have become indispensable in daily life.

The process of creating synthetic polymers often involves reactions between specific monomers to form long chains with desirable properties. These reactions include polymerization methods like addition, condensation, or ring-opening polymerization.

Key characteristics that synthetic polymers can possess include high tensile strength, flexibility, and resistance to chemicals and heat.

The development of synthetic polymers has led to the innovation of materials such as:

• Nylon, which includes variations like Nylon-6 and Nylon-6,6, known for their robustness and elasticity.
• Polyethylene, widely used for packaging due to its toughness and flexibility.
• Polystyrene, popular for its insulation properties and use in packaging materials.

Through understanding synthetic polymers, we can continue to advance in chemistry and material sciences, crafting new materials to suit diverse needs and challenges.