Chain and step polymerization reactions

There are two major kinetic mechanisms for the formation of a polymer, namely, chain polymerization reactions and step polymerization reactions. Typically, vinyl and diene monomers will undergo polymerization by a chain mechanism. Monomers containing, for example, -OH and -COOH functionality will polymerize by a step kinetic mechanism. Ring monomers can polymerize by either a chain or step polymerization mechanism depending on the precise nature of the monomer and method used to start the polymerization reaction. 

It is essential to understand the precise nature of these two very different kinetic processes in order to design and control appropriate polymerization reactors. However, in order to understand more fully the correlations between polymer molecular structure and properties, it is sufficient to examine the nature of the repeat units which are introduced into a linear polymer chain by each mechanism. The dynamic and thermodynamic characteristics of chain 

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SIN simultaneous interpenetrating network, where both polymers are synthesized simultaneously, that is, by chain and step polymerization reactions. 

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