Seeded semibatch emulsion polymerization of n-butyl acrylate.: Kinetics and structural properties

The seeded semibatch emulsion polymerization of n-butyl acrylate was investigated 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 branches were studied. It was found that the amount of gel formed was independent of initiator concentration and monomer feed flow rate if the process proceeded under starved conditions. On the other hand, the higher the initiator concentration and the feeding times, the higher the level of branches but the lower the molecular weights. A high level of branches was found, which was attributed to intramolecular transfer to polymer or backbiting.