What is basic difference between a thermoplastic and thermoset plastic? Give anexample of both type with the corresponding structure.

The basic difference between thermoplastic and thermoset plastic lies in their behavior when heated:

1. Thermoplastic: These are the types of plastics that can be heated and reshaped multiple times. This is due to their polymer structure which consists of individual polymer chains. When heated, these chains can slide past each other, allowing the material to be reshaped. When cooled, the chains lock back into place, retaining the new shape. An example of a thermoplastic is Polyethylene. Its structure consists of long chains of carbon atoms, with two hydrogen atoms attached to each carbon atom.

2. Thermoset Plastic: These plastics, once heated and formed, cannot be reheated and reshaped again. This is because their polymer structure consists of a 3D network of bonded molecules. When heated, these bonds set into a permanent shape. Reheating will not allow the material to be reshaped, but will instead cause it to degrade. An example of a thermoset plastic is Bakelite. Its structure consists of a three-dimensional network of phenol and formaldehyde molecules, bonded together in a rigid structure.

In summary, the main difference between thermoplastics and thermosets is that thermoplastics can be reheated and reshaped, while thermosets cannot.