What is meant by anionic polymerization?
Anionic polymerizations are chain-growth processes in which the active center to which successive monomers are added is a negative ion that is associated with a positive counterion.
What is cationic vinyl polymerization?
Cationic vinyl polymerization is a way of making polymers from small molecules, or monomers, which contain carbon-carbon double bonds. Its primary commercial use is for making polyisobutylene. In cationic vinyl polymerization, the initiator is a cation, which is an ion with a positive electrical charge.
How do you make a cationic polymer?
In chemistry, 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.
What is meant by suspension polymerization?
Suspension polymerization is a process in which monomer(s), relatively insoluble in water, is (are) dispersed as liquid droplets with steric stabilizer and vigorous stirring to produce polymer particles as a dispersed solid phase.
What does anionic mean?
Definition of anionic 1 : of or relating to anions. 2 : characterized by an active and especially surface-active anion.
What is the difference between anionic and cationic polymerization?
Anionic polymerization reactions are initiated by an active anionic species, whereas the cationic polymerization reactions are initiated by an active cationic species. This is the key difference between anionic and cationic polymerization. Both these polymerization reactions are sensitive to the solvent used.
How does cationic polymerization differ from free radical and anionic polymerization?
Anionic polymerization begins with an anion. The process is initiated by nucleophilic addition of an anion to a double bond in the monomer. Cationic polymerization begins with a cation. The cation transfers its electrical charge to the monomer to activate the monomer for polymerization.
Which catalyst is used for cationic polymerization?
Lewis acid catalyst
A Lewis acid catalyst is generally used to initiate the cationic polymerization reaction by activation of the oxetane ring oxygen, allowing nucleophilic attack from the ring oxygen atom of a second oxetane molecule and ring opening.
What is cationic polymerization?
Cationic polymerization is performed to produce oligomers and high polymers of considerable technological importance, for example, polyisobutylene (PIB), polybutenes (copolymers obtained from C4 unsaturated hydrocarbons), and butyl rubber (a random copolymer of isobutylene (IB) and isoprene).
What is cationic polymerization of nonpolar vinyl monomers?
The cationic polymerization of nonpolar vinyl monomers is reviewed from the fundamentals of cationic polymerization to cationic macromolecular engineering.
What is cationic ring-opening polymerization?
Cationic ring-opening polymerization. Cationic ring-opening polymerization follows the same mechanistic steps of initiation, propagation, and termination. However, in this polymerization reaction, the monomer units are cyclic in comparison to the resulting polymer chains which are linear.
What is the process of chain growth polymerization?
is a type of chain growth polymerization in which a cationic initiator transfers a proton to a monomer which then becomes reactive toward chain growth. The cationic polymerization usually proceeds at very high rates both at high and low temperatures. Both the rate of reaction and the molecular weight decreases with increasing temperature.