We cannot deny the presence of polymers in our lives. We are surrounded by objects, most of which, some way or the other have a polymer associated with them. The ease of moulding polymers into different shapes and their relatively low cost of production has been the main reason for their universal usage. Bakelite is one of the commercially manufactured polymers that we witness in our daily lives.
Bakelite is the commercial name for the polymer obtained by the polymerization of phenol and formaldehyde. These are one of the oldest polymers that was synthesised by man. Phenol is made to react with formaldehyde. The condensation reaction of the two reactants in a controlled acidic or basic medium results in the formation of ortho and para hydroxymethylphenols and their derivatives. When the phenol is taken in excess and the reaction medium is made acidic, the product of the condensation reaction obtained is novolac. Whereas, when the quantity of formaldehyde taken is more than that of phenol in the reacting mixture , and the reaction occurs in a basic medium, the condensation product is known as resol.
These intermediate condensation products are used as resins in different industries. Bakelite is obtained when novolac is allowed to undergo cross-linking in the presence of a cross-linking agent. In general, phenol taken in excess acts as the cross-linking agent. The cross-linked product of phenol and formaldehyde have the following structure.
Bakelite has a low electrical conductivity and high resistance to heat and chemicals. It is a thermosetting polymer and has high strength and retains its shape after moulding. Phenolic resins are extensively used as adhesives and binding agents. It finds application in coating industry as well for protective purposes. Bakelite is most commonly used for making electrical switches due to its high resistance to heat and low conductivity. Earlier it was used for making machine parts of electrical systems too. Bakelite is also used to make the handles of variety of utensils. It is one of the most important polymers that are used to make different components and parts. Join BYJU’s to know more about polymers with the most simplified approach of learning.