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CUET
Chemistry
Organic: Polymers
Case: Read the passage and answer the following questions There are two broad types of polymerisation reactions, i.e., the addition or chain growth polymerisation and condensation or step-growth polymerisation. In chain-growth polymerisation, the molecules of the same monomer or different monomers add together on a large scale to form a polymer. This type of polymerisation is explained free radicle mechanism. Some important addition polymers are polythene and teflon. Condensation polymerisation or step-growth polymerisation generally involves a repetitive condensation reaction between two bi-functional or trifunctional monomeric units. Some important condensation polymers are nylon, Bakelite, and formaldehyde polymer. Copolymerisation is a polymerisation reaction in which a mixture of more than one monomeric species is allowed to polymerise and form a copolymer. Rubber and its derivatives are copolymers. |
In addition polymerisation leads to an increase in chain length and chain growth can take place through the formation of; |
Free radicals Ionic species Both of the above None of these |
Both of the above |
This mode of polymerisation leads to an increase in chain length and chain-growth can take place through the formation of either free radicals or ionic species. However, the free radical governed addition or chain growth polymerisation is the most common mode. |