Branching Polymerization of Small Molecules

At the gel point, when in the course of a three-dimensional polymerization reaction a network first appears, its mass is negligible practically all of the polymerizing material still exists as monomers, dimers, trimers, and larger groups which are not bound to the network. As the reaction proceeds after the gel point, more and more of these loose groups become attached to the network, so that its relative mass (the gel fraction ) gradually increases and approaches unity. Approximate equations for the increase in gel fraction with extent of reaction have been given by Flory (1941) and Stockmayer (1943). 

Even after the gel fraction has become 1, all of the polymerizing material having been bound to the network, the reaction may still proceed, as the network strands react with each other to form additional 

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