Question

Arrange the following monomers in increasing order of reactivity,toward anionic polymerization and justify your answer. Arrange the following monomers in increasing order of reactivity toward cationic polymerization and justify your answer.

Polymer Chemistry

Answer 1

Anionic addition polymerization is a form of chain-growth polymerization or addition polymerizationthat involves the polymerization of vinyl monomers with strong electronegative groups.^[3][4] This polymerization is carried out through a carbanion active species.

In order for polymerization to occur with vinyl monomers, the substituents on the double bond must be able to stabilize a negative charge. Stabilization occurs through delocalization of the negative charge. Because of the nature of the carbanion propagating center, substituents that react with bases or nucleophiles either must not be present or be protected.

Basing on this explanation the order would be:

c > a > b

Cl can stabilize better the negative charge, while the Carbonile group do the same thing, however the localization is better with Cl.

Cationic polymerization is a type of chain growth polymerization in which a cationic initiator transfers charge to a monomer which then becomes reactive. This reactive monomer goes on to react similarly with other monomers to form a polymer.

Monomer scope for cationic polymerization is limited to two main types: olefins and heterocyclic monomers. Cationic polymerization of both types of monomers occurs only if the overall reaction is thermally favorable. In the case of olefins, this is due to isomerization of the monomer double bond; for heterocycles, this is due to release of monomer ring strain and, in some cases, isomerization of repeating units. Monomers for cationic polymerization are nucleophilic and form a stable cationupon polymerization.

Basing on this, the order would be:

b) > c) > a)

Hope this helps