It is thermosetting plastics which are most widely used and the most important plastics.
It is formed by condensation reaction of phenol and formaldehyde.
1. It possesses outstanding electrical and mechanical properties.
2. It is resistant to heat, water and many chemicals.
3. It decomposes by concentrated caustic alkalis, sulphuric acid and nitric acid.
1. Uses for making switch boards, aircraft accessories, automobile and telephone.
2. Asbestos is added to increase resistance to heat and chemicals. Moulded sheets having many uses are made by impregnating paper sheets in resins.