Synthesis of acrylic latex via microflow miniemulsion photopolymerization using fluorescent and LED UV lamps

摘要

We show the potential of miniemulsion photo-polymerization for the continuous production of aqueous poly(acrylate) dispersions in a microreactor at room temperature. While the starting acrylate nanoemulsions are amenable to limit scattering, their polymerization within a microreactor provides additionally small microchannels and short diffusion path enabling an efficient mixing in order to alleviate the constraints associated with nonuniform through-cure in turbid medium. Two key features prove that this process design is highly eco-efficient: i) two types of energy-saving and compact UV sources (fluorescent or light-emitting diode) were employed; ii) high conversions were achieved using the fluorescent lamp with short residence times (10 min), low irradiance (3 mW cm2) and without the need of solvent. The present study describes briefly the influence of various parameters -flow rate, photo-initiator type/concentration, droplet size, solid content, UV source - on the photopolymerization course (kinetics) and the properties of the nanolatex obtained (particle size and molecular weight).