Abstract
A new mixer with a perforated screw has been developed for the reactor in which the viscosity of reactants varies in a wide range, from lower to much higher viscosity. This mixer was applied to the continuous polymerization of acrylonitrile in an aqueous medium. It was observed that the reactant slurry overflowing from the reactor with the perforated -screw mixer was less viscous than those from the reactor with a paddle mixer. The reduction in viscosity of the reactant slurry successfully improved the flexibility of operation. In particular, this reduction allowed the concentration of monomer in the feed to be raised to a higher level. Measurement of the sedimentation velocity and the volume of polyacrylonitrile particles, and the permeation rate of water through the sedimented bed of the particles, indicated that the polymer particles produced with the perforated-screw mixer are more compact than those with the paddle mixer. It is confirmed that this compaction makes the reactant slurries less viscous.
