Step Growth Polymerization
Dr. Mamdouh Al-Harthi
Department of Chemical Engineering
KFUPM
Dhahran, KSA
Classifications of polymerization reactions
•Step growth polymerization
•Chain growth polymerization
•Free radical polymerization
•Ionic polymerization
•Coordination polymerization
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Step Growth Polymerization
•Step-growth polymerization is a polymerization process that involves a chemical reaction between multifunctional monomers molecules. In a step-growth reaction, the growing chains may react with each other to form even longer chains.
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Step Growth Polymerization mer
m n mer m mer m Generally
pentamer er trimer tetramer monomer trimer tetramer er er trimer monomer er er monomer monomer −+=−=−=+=+=+=+=+)(dim dim dim dim dim
•Any two molecular species can react.
•Monomer disappears early.
•Polymer MW rises throughout.
•Growth of chains is usually slow (minutes to days).
•Long reaction times increase MW, but yield of polymer hardly changes. •All molecular species are present throughout.
>reaction between pvp and amino

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