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Home , Cationic polymerization, Chain transfer, Ionic polymerization, Living polymerization, Radical anion

1 Reaction

Chain Growth / Condensation Addition Polymerization Polymerization

Ionic Polymerization 2 Chain Growth / Addition Polymerization Free Polymerization

Free ’s are chain polymerization’s in which each grows by addition of to a terminal free-radical reactive site known as active center.

1 Initiation 2 Propagation 3 Termination 2 Chain Growth / Addition Polymerization Free Radical Polymerization

Free radical polymerization’s are chain polymerization’s in which each polymer molecules grows by addition of monomer to a terminal free-radical reactive site known as active center. Initiation 3 Generating free radical from initiator and monomer Initiation 4 Generating free radical from initiator and monomer Propagation 5 Rapid and progressive addition of monomer to the growing 6 Destruction of the growth activity of the chain

Dispropotional

Coupling Termination Termination 7 Coupling / Combination Coupling Two growing polymer chain yield a single polymer terminated at each end by an initiator fragment

Coupling Termination 8 Dispropotional CouplingDispropotio While in disproportionation a labile atom (usually hydrogen) is nal transferred from one polymer radical to another

Saturated Unsaturated

Dispropotional 9

Initiation CouplingTermination

Free Radicalic Ideal Propagation Polymerization (FRP) Chain Transfer Chain Transfer Free Radicalic a growing polymer chain is deactivated or terminated by Polymerization transferring its growth activity to a previously inactive species 10 Chain Transfer

To Solvent

To Monomer Chain Transfer To Initiator

To Polymer 11 Chain Growth / Addition Polymerization Products : Step Growth Polymerization 12 Condensation Polymerization

These often (but not always) occur with loss of a small byproduct, such as water, and generally (but not always) combine two different components in an alternating structure

Nylon 6,6 Polyester (Dacron) Polycarbonat Step Growth Polymerization 13 Condensation Polymerization

Condensation polymerization : 1. More slowly than addition polymerization 2. Often requiring heat, and 3. They are generally lower in molecular weight. Step Growth Polymerization 14

Condensation Polymerization By Product / condensation Step Growth Polymerization 15

Condensation Polymerization By Product / condensation Step Growth Polymerization 16 Condensation Polymerization

Polymerization Polymerization Reaction

Chain Growth / Addition Polymerization Condensation Polymerization

Living Polymerization Ionic Polymerization 17 Kind of Chain Reaction Polymerization Ionic polymerizations involve chain carriers or reactive centers that are organic or charged organic groups

Ionic Polymerization

Anionic Polymerization the growing chain end carries a negative charge or carbanions the growing chain end with a positive charge or carbonium (carbocation) ion Cationic Polymerization 18 the growing chain end Cationic Polymerization with a positive charge or carbonium (carbocation) ion with electron-donating groups like form stable positive charges and are readily converted to by cationic catalysts

Initiation

Propagation

Termination

Chain Transfer Cationic Polymerization 19 the growing chain end Cationic Polymerization with a positive charge or carbonium (carbocation) 1 Initiation ion

Any strong Lewis like (BF3) or Friedel–Crafts catalysts such as AlCl3 can readily initiate cationic polymerization in the presence of a cocatalyst like water. During initiation, a proton adds to the monomer to form a carbonium ion Cationic Polymerization 20 the growing chain end Cationic Polymerization with a positive charge or carbonium (carbocation) 2 Propagation ion

In the presence of monomer, the chain can grow by the attack of carbocation Cationic Polymerization 21 the growing chain end Cationic Polymerization with a positive charge or carbonium (carbocation) 3 Termination + Chain Transfer ion Cationic Polymerization 22 the growing chain end Cationic Polymerization with a positive charge or carbonium (carbocation) 3 Termination + Chain Transfer ion Cationic Polymerization 22 the growing chain end Cationic Polymerization with a positive charge or carbonium (carbocation) 3 Termination + Chain Transfer ion Anionic Polymerization 23 Anionic Polymerization the growing chain end carries a negative charge or carbanions ion

Monomer for Anionic Polymerization Initiation

Propagation Anionic Polymerization 24 Anionic Polymerization the growing chain end carries a 1 Initiation negative charge or carbanions ion

A classical example is the polymerization of with butyllithium as initiator. Another common initiator is the of , naphthalide. Its cheapness makes it acceptable for industrial application Anionic Polymerization 25 Anionic Polymerization the growing chain end carries a 2 Propagation negative charge or carbanions ion

The carbanion now reacts with another monomer molecule in just the same manner as the initiator reacted with the first monomer molecule; another carbanion is generated. This keeps happening, and each time another monomer is added to the growing chain, a new anion is generated allowing another monomer to be added. Anionic Polymerization 26 Anionic Polymerization the growing chain end carries a Living chain end negative charge or carbanions ion

No natural termination step, because the chain is mutually repulsive each other

Special case, transfer to solvent TERMINATION that is able to Repulsion release proton Anionic Polymerization 27 Anionic Polymerization the growing chain end carries a negative charge or carbanions ion

If all the monomer is allowed to react, the degree of polymerisation xn in an anionic polymerisation is adjustable and depends just on two concentrations. It is identical to the monomer (M)-to-initiator (I) ratio if an initiator such as BuLi is used in THF as solvent. Anionic Polymerization 28 Anionic Polymerization the growing chain end carries a negative charge or carbanions ion

Advantage Disadvantage 1. Homopolymer with narrow Molecular 1. Require rigorous purification process Weight Distribution (repeated distillation of solvent, degas of 2. Can cop living polymer with specific end H2O and O2, reactor must be cleaned groups under vacuum over night) 3. Able to make sequential monomer 2. Inappropriate for many functional addition monomer especially with labile proton Polymerization Reaction

Condensation Polymerization Chain Growth / Addition Polymerization

Ionic Polymerization Living Polymerization Living Polymerization 29 Living polymerization doesn’t mean alive in the biological sense. As defined by the International Union of Pure and Applied Chemistry (IUPAC) definition, living polymerization is a chain polymerization from which chain transfer and chain termination are absent Living Polymerization 29

Living polymerization, which has been studied for more than 70 years, can follow anionic, cationic, and radical polymerization mechanisms. Popular atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) are examples of living radical polymerization. Living polymerization allows you to obtain precisely controlled molecular weight and narrow molecular weight distribution, as well as complex polymer architectures.

Practical Applications : SMART POLYMER