Question

Distinguish between
a. Manmade material and natural material
b. Thermoplastic and thermosetting plastic.

Answer 1

a. Manmade material and natural material:
Manmade materials:
1. Natural materials are those material, which occur in nature by its own.
2. They are both renewable and non-renewable in nature.
3. They help in economic development of people.
4. They are eco-friendly.
5. They are not manufactured in factories.
4. Examples : wood, glass, plastic, thread, soil, metals, rubber etc.
Man made materials:
1. Man-made materials are a type of material that doesn't occur naturally and is made by humans.
2. They are non-renewable in nature.
3. They help in economic as well as social development
4. They are not environmental friendly.
5. They are not manufactured in factories.
4. Examples : glass, plastic, artificial thread, thermocol etc .



b. Thermoplastic and thermosetting plastic:

Thermoplastic polymers	Thermosetting polymers
These are formed by addition polymerisation	These are formed by condensation polymerization
Generally more expensive than thermosettings	Cost effective
Monomer used in these is generally bifunctional	In this monomer used is tri, tetra or polyfunctional
Aesthetically-superior finishes	More difficult to surface finish
They are long chain linear polymer with negligible cross links	These have three- dimensional network structure with number of cross links
less resistant to high temperatures	More resistant to high temperatures than thermoplastics
They have low molecular wt.	They have high molecular wt
They are soft, weak , brittle	They,are hard, strong and more brittle
Highly recyclable	Cannot be recycled
They can be softened and reshaped and reused.	They cannot be softened and reshaped again once again.Highly flexible design
High-impact resistance	Low-impact resistance
Remolding/reshaping capabilities	Cannot be remolded or reshaped
Eco-friendly manufacturing	Eco-foe manufacturing
e.g.- polyethylene, polystyrene, PVC, PVA etc.	e.g.- phenol formaldehyde, ureaformaldehyde, nylon 6:6 etc.