UNIT III NON-METALLIC MATERIALS

1. PLASTICS

2. PLASTICS
• It is a organic polymer
• It can be moulded in to any desired shape with
the help of heat.
• Properties such as:
– Low cost
– Color range
– Water resistance
– Low electrical and thermal conductivity.

3. SOURCES OF RAW MATERIALS OF
PLASTICS
• Animals and vegetables by products.
• Coal by products (Distillation of coal)
• Petroleum by products ( refining of crude oil)

4. CLASSIFICATION OF PLASTICS
• THERMO PLASTICS
• THERMO SETS
– THERMO PLASTICS:
• Plasticity increases with increase in temperature
• Its liquid when heated hardened when cooled
• Its are soft and ductile
– THERMOSETS:
• Permanent hard , not soften when heated
• It cannot be remoulded
• Its harder, stronger, more resistance to heat.

5. COMMODITY AND ENGINEERING
PLASTICS
• Commodity plastics are used for a commodity
purpose( home).
• Engineering plastics are used for the
engineering purpose.
• Both plastics are having
– Thermo plastics
– Thermo sets plastics.

8. IMPORTANT THERMOPLASTICS
• Polythenes
• Polystyrenes
• Polyvinyls
• Acrylics
• Polyamides(Nylones)
• Polytetrafluoro ethylenes(Teflon)
• Cellylosics

9. IMPORTANT THERMOSETTING
PLASTICS:
• Polyesters
• Phenolic
• Urea formaldehyde
• Melamine formaldehyde
• Epoxides.