Sustainable Light-Stimulated Synthesis of Cross-Linked Polymer Microparticles

The increasing demand for crosslinked polymer microparticles (PMPs) in advanced applications requires the development of new sustainable methods which can reduce the impact of the polymerization process on the environment. This research reports a new environmentally-friendly light-assisted polymerization method for the synthesis of highly cross-linked polymer microspheres by combining light-induced [2+2] cycloadditions with dispersion polymerization. Using naturally-occurring coumarin as reactive moieties, this method allows the synthesis of highly crosslinked PMPs in the presence of UV light at room temperature without initiator. The effect of the reaction parameters such as monomer concentration, stabilizer and reaction time on the particle size and yield are investigated using a number of techniques including Fourier transform infrared spectroscopy, solid-state C-13 nuclear magnetic resonance spectroscopy, and scanning electron microscopy. The results show the formation of highly crosslinked porous microspheres which demonstrate good thermal stability.