Polymers

A common biodegradable polyamide copolymer is nylon 2-nylon 6, a copolymer of glycine (forming nylon 2) and aminocaproic acid (forming nylon 6). It is biodegradable due to its peptide-like structure.
Answer: Nylon 2-nylon 6.

Nylon 6,6 is a polyamide formed by condensation polymerization of hexamethylenediamine ( ) and adipic acid ( ).
The reaction forms amide bonds, releasing water molecules.

Nylon 6,6 is a synthetic polymer made by the condensation reaction between hexamethylenediamine and adipic acid. The reaction is a type of step-growth polymerization, and the formation of the polymer is as follows: The chemical reaction is: The reaction occurs in two steps: 1. The amine group of hexamethylenediamine reacts with the carboxyl group of adipic acid to form an amide linkage, releasing water. 2. This reaction repeats to form long polymer chains of nylon 6,6. Thus, nylon 6,6 is formed by the condensation polymerization of hexamethylenediamine and adipic acid.

Step 1: Understand the structure of natural rubber.
Natural rubber is a polymer made from the monomer isoprene, which is a diene compound. The polymerization of isoprene molecules results in the formation of polyisoprene, commonly known as natural rubber. Step 2: Identify the correct monomer.
The monomer of natural rubber is isoprene ( ). Thus, the correct answer is (A).

Part 1: Types of Polymers Based on Intermolecular Forces
Based on the magnitude of intermolecular forces, polymers are classified into four types:


Elastomers: These polymers have the weakest intermolecular forces, which allow them to be stretched. The polymer chains are held together by weak van der Waals forces. Example: Buna-S, Neoprene.
Fibres: These polymers have strong intermolecular forces, such as hydrogen bonding or dipole-dipole interactions. These strong forces lead to close packing of chains and give them high tensile strength. Example: Nylon-6,6, Terylene.
Thermoplastics: These polymers have intermolecular forces that are intermediate between elastomers and fibres. They can be repeatedly softened by heating and hardened by cooling. Example: Polyethylene, PVC.
Thermosetting Polymers: These polymers form extensive cross-links between chains when heated, leading to a hard, infusible, and insoluble mass. They cannot be remolded once set. Example: Bakelite, Urea-formaldehyde resin.

Part 2: Uses of Low-Density Polyethylene (LDPE)
Low-density polyethylene is a chemically inert and flexible material. Two common uses are:


Packaging Film: It is widely used to make plastic bags, grocery bags, and packaging films.
Insulation for Wires and Cables: Its flexibility and excellent electrical insulation properties make it suitable for insulating electrical wires and cables.

Step 1: Understanding the Concept:
Teflon is a synthetic fluoropolymer of tetrafluoroethene. It is well-known for its non-reactive and non-stick properties.
Step 2: Detailed Explanation:
The monomer for Teflon is tetrafluoroethene ( ).
When it undergoes polymerization under high pressure and in the presence of a catalyst, it forms the polymer:

The name of this polymer is Polytetrafluoroethene.
Step 3: Final Answer:
The chemical name of Teflon is Polytetrafluoroethene.

Step 1: Understanding the Concept:
High-Density Polyethylene (HDP) is a polymer produced from ethylene. Unlike Low-Density Polyethylene (LDP), it requires specific low-pressure conditions and a specialized coordination catalyst.
Step 2: Detailed Explanation:
The polymerization of ethene into HDP is carried out at temperatures of to and under a pressure of atmospheres.
The catalyst used is the Ziegler-Natta catalyst, which is a combination of triethyl aluminium and titanium tetrachloride .
This catalyst allows the formation of linear chains that pack closely together, resulting in high density and high tensile strength.
Step 3: Final Answer:
The catalyst used for High-Density Polyethylene (HDP) is the Ziegler-Natta catalyst.

Step 1: Understanding the Concept:
Natural rubber is a linear polymer of isoprene (cis-1,4-polyisoprene). Isoprene is the fundamental monomer unit.
Step 2: Detailed Explanation:
The isoprene molecule consists of a four-carbon chain with two double bonds (a conjugated diene) and a methyl group as a substituent.
IUPAC Name: 2-Methyl-1,3-butadiene.
Structure:

When it polymerizes, the double bonds shift to the center to form the polymer chain.
Step 3: Final Answer:
The chemical structure of the isoprene unit is .

Step 1: Understanding the Concept:
Nylon-6 is a polyamide formed from a single monomer, epsilon-caprolactam, through ring-opening polymerization.
Step 2: Detailed Explanation:
The monomer Caprolactam is heated with water at high temperatures (533 K to 543 K).
The water causes the ring to open, and the resulting amino acid chains polymerize to form Nylon-6.
Reaction:

Step 3: Final Answer:
Nylon-6 is prepared by heating caprolactam with water at about 533-543 K.