Plastics and it's uses in engineering

PLASTIC

Plastic is a mixture of carbon, nitrogen, hydrogen & other element together by the 

polymerization action.

there are 2 types of plastic on basis of temp hardness 

1). thermosetting plastic

❖ these plastic set into permanent shape by high temp 

❖ Reheating process cannot change their shape.

❖ this plastic set at temp of 127°C – 143°C

❖ example – plastic point, phenol formaldehyde, P.V.C flooring (PU) (polymerized 

units)

2). thermoplastic

❖ Thermoplastic becomes soft when heated and if cool down then fix their shape.

❖ Heat treatment process can happen lot of times.

❖ it's fix at temp of 50°C

❖ Example – polythene bags, plastic bottles, PVC pipes, PVC sheets

Use of plastic in building construction

Door & windows, flooring, Panels, roof set, point, water tank, PVC pipes & decorating 

members.

Properties of plastic

1. specific gravity ➔ 1.30 – 1.40

2. plastic should be acid resistant

3. It must stand in high temp (more than 50°C)