Question

What is the full PVC (radical polymerization) reaction? Provide the full mechanism with arrows included. In addition, label the initiation, elongation, and termination steps.

Answer 1

a.Anionic Addition Polymerization:

An anionic initiator will generate a carbanion as an intermediate and thus the polymerization is of anionic addition type. Here the active group of the propagating species is negatively charged. Hence it occurs easily with monomers containing electron withdrawing groups such as phenyl, nitrile etc., which are able to stabilize the propagating species.

1. Chain initiation: Initiation can be brought about by reagents such as n-butyl lithium or potassium amide. In the initiation step, the base adds to a double bond to form a carbanion.

1. Chain propagation: In the chain propagation, this carbanion adds to the double bond and   the process repeats to form a long chain.

1. Chain termination: The chain reaction can be terminated by addition of an acid.