Seeded semibatch emulsion polymerization of n-butyl acrylate. Kinetics andstructural properties

The seeded semibatch emulsion polymerization of n-butyl acrylate was invest igated using potassium persulfate as initiator at 75 degrees C. The effect of initiator concentration and monomer feeding time (feed flow rate) on the kinetics, fraction of gel, molecular weight distributions, and level of br anches were studied. It was found that the amount of gel formed was indepen dent of initiator concentration and monomer feed flow rate if the process p roceeded under starved conditions. On the other hand, the higher the initia tor concentration and the feeding times, the higher the level of branches b ut the lower the molecular weights. A high level of branches was found, whi ch was attributed to intramolecular transfer to polymer or backbiting.