A New Insight for Synthesizing Polymeric Nano-Microspheres with Different Size by Using Different Initiators in the Conventional Emulsifier-Free Emulsion Polymerization
Using different initiators, potassium persulphate (KPS) and azodiisobutyronitrile (AIBN), two conventional emulsifier-free emulsion polymerizations of the monomer tert-butyl acrylate (t-BA) in aqueous medium were carried out. The results of the measurements on the transmittance of the reaction system and the conversion of the monomer through UV-Vis absorption spectroscopy indicate that the polymerization processes of the t-BA initiated by KPS shows three stages while that initiated by AIBN behaves two stages. Investigations on the morphology and the average hydrodynamic diameter and its distribution of the obtained poly (t-BA) nano-microspheres by scanning electron microscope and dynamic light scattering techniques show that, during the polymerization, the poly(t-BA) nano-microspheres from AIBN initiated polymerization show a larger average hydrodynamic diameter and a steady diameter’s distribution. The results have prompted us to have a new insight in emulsifier-free emulsion polymerization and provide us a new idea and a convenient approach to synthesize polymeric nano-microspheres with a different hydrodynamic diameter by using initiator with required solubility in aqueous medium through free-radical polymerization.