Gelation in the non-stoichiometric step growth polymerization of two- and three-functional monomers

A random step grow polymerization of two-functional (A(2)) and three-functional (B(3)) monomers was studied using a computer simulation method. The focus was on the effect of dividing the process into stages onto the weight-average polymerization degree (P) of the resulting polymeric product. It was found that by applying the procedure one can bring to gelation a system that does not form a network when polymerized in a single stage. Such an effect known previously as a result of changes in stoichiometry of a system, can also be observed when the ratio of monomers is the same throughout the whole process. Then, the gelation stems from the growth history of macromolecules.