Addition or Chain-Reaction Polymerization

The most common chain reaction polymerization is free-radical polymerization. A free radical is merely a molecule with an unpaired electron, which has a tendency to add a supplementary electron in order to form an electron pair which makes it extremely reactive. These molecular complexes could be produced by heat or irradiation, or formed by the addition of a compound, named the initiator (I), for example, dialkyl peroxides (R compounds (R — N = N — R), which are not strictly, catalysts, since they are chemically altered during the reaction [196], 

During this phase, the initiated monomer rapidly adds another monomer to a chain by the addition of a free radical to the double bond of a monomer with the generation of another free radical [196], That is, in the propagation phase, due to the development of the electron transfer process, the resulting movement of the active center down the chain results in the production of the polymer [195], 

Rao and J. Gopalakrishnan, New Directions in Solid State Chemistry (2nd edition), Cambridge University Press, Cambridge, UK, 1997. 

Kempen, PhD thesis, Department of Chemistry, University of Stuttgart, Stuttgart, Germany, 2001. 

Fujita and R.W. Cahn, Physics of New Materials, Springer-Verlag, New York, 1998. 

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