Question

How does free radical polymerization of buta-1,3-diene take place?

Answer 1

substances called Initiators which generate the chain – initiating species. Initiator molecules contain O – O or S – S or N – O bonds. [Initiators are of peroxide type (containing O – O bonds)]. Some examples of initiators, (i) Acetyl peroxide (AC2O2) (ii) Benzoyl peroxide (BZ2O2 (iii) 2, 2’ – Azobis – isobutronitrile (AIBN) Production of chain initiating species by initiators is explained as follows I2 -------> 2 I. where I is initiator II) Propagation Here the initiator attack the butadiene and further polymerisation occur and the carbon chain grows (iii) Termination Chain termination is brought about by bimolecular reaction between reactive radical centres. coupling or combination Free – radical of one – chain combines with free – radical of another to form a covalent bond.