Preparation of Polystyrene Microspheres Using Rosin–Acrylic Acid Diester as a Cross-Linking Agent

Reacting acrylic rosin with 2-hydroxyethyl methacrylate (HEMA) produced an ester (acrylic rosin ester, RAH) with double bonds that was used as a cross-linking monomer for the preparation of polystyrene microspheres through suspension polymerization, replacing the traditional monomer divinyl benzene. The effects of monomer weight ratio, reaction temperature, gelatin level, and stirring speed on the polymer microspheres were investigated. The structures, morphologies , and properties of the polymer microspheres were analyzed and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, optical microscopy, and laser particle size analysis. The results indicated that the polymer microspheres with the best spherical shape were prepared with a monomer weight ratio of <i>m</i><sub>St</sub>/<i>m</i><sub>RAH</sub> = 2:1, with azodiisobutyronitrile and gelatin in the amounts of 1 and 6 wt % of total monomers. The particle size of the polymer microspheres varied with the reaction conditions.