user
Explain me about Non-Metals Materials.
assistant
Timber: This is a relatively low cost material and a bad conductor of heat and electricity. 
It has also good elastic and frictional properties and is widely used in foundry 
patterns, structural and as water lubricated bearings. 
Leather: This is widely used in engineering for its flexibility and wear resistance. It is
widely used for belt drives, washers and such other applications. 
Rubber: It has high bulk modulus and is used for drive elements, sealing, vibration 
isolation and similar applications. 
Plastics: These are synthetic materials which can be moulded into desired shapes under 
pressure with or without application of heat. 
A. Thermosetting Plastics: It initially softens and with increasing heat and pressure, 
polymerisation takes place. This results in hardening of the material. These plastics cannot be
deformed or remoulded again under heat and pressure. 
B. Thermoplastics: Thermoplastics do not become hard with the application of heat and pressure 
and no chemical change takes place. They remain soft at elevated temperatures until they are 
hardened by cooling. These can be re-melted and remoulded by application of heat and 
pressure.