Molecular weight distribution of step-growth comb-branched polymers

A probability model is developed for determining the average properties of the comb-branched polymer formed through random connection of two different types of polymer chains with one type as the backbone and the other as side chains. M̄_n, M̄_w and other higher average molecular weights can all be described as a function of the reaction conversion and the average properties of two polydispersed polymer chains directly without the knowledge of the whole distributions. The simulation results indicate that, as the molecular weight of the backbone polymer is usually much larger than that of the side chain polymer, the polydispersity of the resulting comb polymers is mainly determined by the polydispersity of the backbone at the end of the reaction.