Question

Mention the types of polymers formed on the basis of intermolecular forces. Write any two uses of low density polyethylene.

Hint:

A simple way to remember the polymer types by force: Elastomers are weak and stretchy (rubber bands), Fibres are strong and thread-like (clothing), Thermoplastics can be reshaped with heat (plastic bottles), and Thermosetting polymers set permanently with heat (pot handles).

Answer 1

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.